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WO2021050612A1 - Compositions et méthodes pour le traitement du virus respiratoire syncytial - Google Patents

Compositions et méthodes pour le traitement du virus respiratoire syncytial Download PDF

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Publication number
WO2021050612A1
WO2021050612A1 PCT/US2020/050022 US2020050022W WO2021050612A1 WO 2021050612 A1 WO2021050612 A1 WO 2021050612A1 US 2020050022 W US2020050022 W US 2020050022W WO 2021050612 A1 WO2021050612 A1 WO 2021050612A1
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WIPO (PCT)
Prior art keywords
optionally substituted
conjugate
formula
pharmaceutically acceptable
acceptable salt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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PCT/US2020/050022
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English (en)
Inventor
Allen Borchardt
Thomas P. Brady
Zhi-yong CHEN
Quyen-Quyen Thuy Do
Travis James HAUSSENER
Alain Noncovich
Leslie W. TARI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cidara Therapeutics Inc
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Cidara Therapeutics Inc
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Filing date
Publication date
Priority to MX2022002842A priority Critical patent/MX2022002842A/es
Priority to EP20863252.1A priority patent/EP4028392A1/fr
Priority to JP2022515651A priority patent/JP2022547538A/ja
Priority to CN202080077245.8A priority patent/CN114728937A/zh
Priority to CA3153626A priority patent/CA3153626A1/fr
Priority to AU2020345850A priority patent/AU2020345850A1/en
Application filed by Cidara Therapeutics Inc filed Critical Cidara Therapeutics Inc
Publication of WO2021050612A1 publication Critical patent/WO2021050612A1/fr
Priority to EP21762918.7A priority patent/EP4192512A1/fr
Priority to TW110129179A priority patent/TW202220698A/zh
Priority to US18/019,944 priority patent/US20230364251A1/en
Priority to PCT/US2021/045074 priority patent/WO2022032175A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/12—Antivirals
    • A61P31/14—Antivirals for RNA viruses
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D417/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00
    • C07D417/14—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing three or more hetero rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D471/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00
    • C07D471/12—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00 in which the condensed system contains three hetero rings
    • C07D471/20—Spiro-condensed systems
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
    • C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
    • C07D487/04—Ortho-condensed systems

Definitions

  • RSV respiratory syncytial virus
  • RSV is a common infection in infants, almost all of whom will be infected in the first 24 months of life. Severe disease resulting from RSV infection is estimated to be the cause of approximately 3.2 million hospitalizations worldwide and around 66,000 deaths in children less than 5 years old. The development of antiviral treatments for RSV has been a continuing challenge.
  • Palivizumab a monoclonal antibody, is approved for prophylactic use but is only 60% effective at reducing hospitalization rates.
  • Ribavirin is approved as an inhaled treatment option in infants but has very limited efficacy and significant safety concerns for caregivers.
  • the standard of care for RSV-infected patients is supportive, including fluids and oxygen. New, more effective therapies for treating RSV are needed.
  • conjugates contain monomers or dimers of a moiety that inhibits respiratory syncytial virus (RSV) fusion protein (F protein) (e.g., Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof) conjugated to Fc monomers, Fc domains, Fc-binding peptides, albumin proteins, or albumin protein-binding peptides.
  • RSV respiratory syncytial virus
  • F protein fusion protein
  • the RSV F protein inhibitor (e.g., Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof) in the conjugates targets RSV fusion protein on the surface of the viral particle.
  • the Fc monomers or Fc domains in the conjugates bind to FcgRs (e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb) on immune cells, e.g., neutrophils, to activate phagocytosis and effector functions, such as antibody-dependent cell- mediated cytotoxicity (ADCC), thus leading to the engulfment and destruction of viral particles by immune cells and further enhancing the antiviral activity of the conjugates.
  • ADCC antibody-dependent cell- mediated cytotoxicity
  • the albumin or albumin-binding peptide may extend the half-life of the conjugate, for example, by binding of albumin to the recycling neonatal Fc receptor.
  • Such compositions are useful in methods for the inhibition of viral growth and in methods for the treatment of viral infections, such as those caused by an RSV A and RSV B.
  • the invention features a conjugate described by any one of formulas (D-I), (M-I), (1), or (2): wherein each A 1 and each A 2 is independently selected from any one of formulas (A-I)-(A-VI):
  • Q is selected from optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 2 -C 20 alkenyl, optionally substituted C 3 -C 20 cycloalkenyl, optionally substituted C 2 -C 20 alkynyl, optionally substituted C 5 -C 20 aryl, optionally substituted C 2 -C 15 heteroaryl, and optionally substituted C 1 -C 20 alkoxy;
  • R1, each X1, and Y are each independently selected from:
  • R 2 , each R 3 , each X 2 , U 1 , each M 1 , each M 2 , each K 1 , and each K 2 are each independently selected from OH, halogen, nitrile, nitro, optionally substituted amine, optionally substituted imine, optionally substituted C 1 -C 20 alkamino, optionally substituted sulfhydryl, optionally substituted carboxyl, optionally substituted cyano, optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 alkenyl, optionally substituted C 3 -C 20 cycloalkenyl, optionally substituted C 2 -C 20 alkynyl, optionally substituted C 5 -C 20 aryl, optionally substituted C 2 -C 15 heteroaryl, and optionally substituted C 1 -C 20 alkoxy; each X3 is independently selected from optionally substituted C 1 -
  • each A 1 -L or each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L or A 1 -L- A 2 structures described herein).
  • n is 2 and each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1- 138).
  • each A 1 and each A 2 is independently described by formula (A-III) and U 3 is a substituent of the ring atom Ua.
  • Ua is CH.
  • Ua is N.
  • each A 1 and each A 2 is independently described by any one of formulas (A-IIIa)-(A-IIIf): or a pharmaceutically acceptable salt thereof.
  • each A 1 and each A 2 is independently described by any one of formulas (A-IIIb)-(A-IIIf). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIb) or (A-IIIc). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-IIId)-(A-IIIf). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIc) or (A-IIIf). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIb). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIc).
  • each A 1 and each A 2 is independently described by formula (A-IIId). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIe). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IIIf). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas or a pharmaceutically acceptable salt thereof. In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-IVa)-(A-IVc). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-IVd)-(A-IVf).
  • each A 1 and each A 2 is independently described by formulas (A-IVa) or (A-IVd). In some embodiments, each A 1 and each A 2 is independently described by formulas (A-IVb) or (A-IVe). In some embodiments, each A 1 and each A 2 is independently described by formulas (A-IVc) or (A-IVf). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IVa). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IVb). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IVc). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IVd).
  • each A 1 and each A 2 is independently described by formula (A-IVe). In some embodiments, each A 1 and each A 2 is independently described by formula (A-IVf). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-IIIb)-(A-IIIf), (A-IV), (A-V), or (A-VI). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-IIIb), (A-IIIc), (A-IV), (A-V), or (A-VI).
  • each A 1 and each A 2 is independently described by any one of formulas (A-IIIa)-(A-IIIc), or (A-IVa)-(A-IVc). In some embodiments, each A 1 and each A 2 is independently described by any one of formulas (A-III) or (A-IV), wherein each p is 1; wherein each p is 2; or wherein each p is, independently, 1 or 2.
  • each A 1 and each A 2 is independently described by formula (A-III) (e.g., any one of formulas (A-IIIa)-(A-IIIf) or any one of formulas (A-IIIb)-(A-IIIf)), wherein each U 3 is described by: , wherein U b is C or O; and U4 is selected from optionally substituted amino, optionally substituted imine, optionally substituted C 1 -C 20 alkamino, optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 5 -C 15 aryl, optionally substituted C3- C15 heteroaryl, and a bond.
  • A-III e.g., any one of formulas (A-IIIa)-(A-IIIf) or any one of formulas (A-IIIb)-(A-IIIf)
  • each U 3 is described by:
  • each A 1 and each A 2 is independently described by formula (A-III) (e.g., any one of formulas (A-IIIa)-(A-IIIf) or any one of formulas (A-IIIb)-(A-IIIf)), wherein each U 3 is described by:
  • each A 1 and each A 2 is independently described by formula (A-IV) (e.g., any one of formulas (A-IVa)-(A-IVf)), wherein each U 3 is an optionally substituted C1-C6 alkyl (e.g., -(CH 2 )4, -(CH 2 )3CN, -(CH 2 )4F, -(CH 2 )4OH, -(CH 2 )2SO2Me, -(CH 2 )3SO2CH 2 Me, or -(CH 2 )3SO2Me).
  • C1-C6 alkyl e.g., -(CH 2 )4, -(CH 2 )3CN, -
  • formula (A-III) e.g., any one of formulas (A-IIIa)-(A-IIIf) or any one of formulas (A-IIIb)-(A-IIIf)
  • the conjugate is described by formula (M-I) or (D-I).
  • the invention features a conjugate described by formula (D-I): wherein each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138); L in each A 1 -L-A 2 is a linker covalently attached (e.g., by way of a covalent bond or linker) to a sulfur atom of a hinge cysteine in E and to each of A 1 and A 2 ; n is 1 or 2 (e.g., when n is 2, the two Fc domain monomers dimerize to form and Fc domain); T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), and the squiggly line connected to the E indicates that each A 1 -L-A 2 is covalently attached to a sulfur atom
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138);
  • L in each A 1 - L-A 2 is a linker covalently attached to a nitrogen atom of a surface exposed lysine in E and to each of A 1 and A 2 ;
  • n is 1 or 2 (e.g., when n is 2, the two Fc domain monomers dimerize to form and Fc domain);
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), and the squiggly line connected to the E indicates that each A 1 -L-A 2 is covalently attached (e.g., by way of a covalent bond or linker) to the nitrogen atom of a surface exposed lysine in E, or a pharmaceutically acceptable salt thereof.
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138);
  • L in each L-A 1 is a linker covalently attached to a sulfur atom of a hinge cysteine in E and to A 1 ;
  • n is 1 or 2 (e.g., when n is 2, the two Fc domain monomers dimerize to form and Fc domain);
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20); and the squiggly line connected to E indicates that each L-A 1 is covalently attached to the sulfur atom of the hinge cysteine in E, or a pharmaceutically acceptable salt thereof.
  • each A 1 may be independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138);
  • L in each L-A 1 is a linker covalently attached to a nitrogen atom of a surface exposed lysine in E and to A 1 ;
  • n is 1 or 2 (e.g., when n is 2, the two Fc domain monomers dimerize to form and Fc domain);
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), the squiggly line connected to E indicates that each L-A 1 is covalently attached (e.g., by way of a covalent bond or linker) to the nitrogen atom of a surface exposed lysine in E, or a pharmaceutically acceptable salt thereof.
  • each A 1 may be independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138);
  • L in each A 1 -L-A 2 is a linker covalently attached to a sulfur atom of a hinge cysteine in each E and to each of A 1 and A 2 ;
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), and the two squiggly lines connected to the two Es indicate that each A 1 -L-A 2 is covalently attached to a pair of sulfur atoms of two hinge cysteines in the two Es, or a pharmaceutically acceptable salt thereof.
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138);
  • L in each L-A 1 is a linker covalently attached to a sulfur atom in a hinge cysteine in E and to A 1 ;
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), and the two squiggly lines connected to the two sulfur atoms indicate that each L-A 1 is covalently attached to a pair of sulfur atoms of two hinge cysteines in the two Es, or a pharmaceutically acceptable salt thereof.
  • each A 1 may be independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • each E includes an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138.
  • At least one of the pair of sulfur atoms is the sulfur atom corresponding to (e.g., the sulfur atom of) a hinge cysteine of SEQ ID NO: 10 or SEQ ID NO: 11, i.e., Cys10, Cys13, Cys16, or Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11.
  • the pair of sulfur atoms are the sulfur atoms corresponding to (e.g., the sulfur atoms of) Cys10 and Cys13 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys10 and Cys16 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys 30 and Cys18 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys13 and Cys 36 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys13 and Cys 38 in SEQ ID NO: 10 or SEQ ID NO: 11, and/or Cys 36 and Cys 38 in SEQ ID NO: 10 or SEQ ID NO: 11.
  • the sulfur atoms are the sulfur atoms corresponding to (e.g., the sulfur atoms of) Cys10 and Cys13 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys10 and Cys16 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys 30 and Cys18 in SEQ ID NO: 10 or SEQ ID NO: 11, Cys13 and
  • the pair of sulfur atoms are (e.g., the sulfur atoms corresponding to) Cys10 and Cys13 in SEQ ID NO: 10 or SEQ ID NO: 11 or Cys 36 and Cys 38 in SEQ ID NO: 10 or SEQ ID NO: 11.
  • the pair of sulfur atoms include one sulfur atom of a cysteine from each E, i.e., L-A along with the sulfur atoms to which it is attached forms a bridge between two Fc domains (e.g., two Fc domains including the sequence of SEQ ID NO: 10 or SEQ ID NO: 11 ).
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E;
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E;
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E;
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys18 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E;
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E; the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys16 of SEQ ID NO: 10 or SEQ ID NO: 11 from another E;
  • the conjugate has the structure: wherein each of a, b, c, and d is, independently, 0 or 1 and wherein when a, b, c, or d is 0, the two sulfur atoms form a disulfide bond.
  • a is 1 and b, c, and d are 0.
  • a and b are 1 and c and d are 0.
  • a and c are 1 and b and d are 0.
  • a and d are 1 and b and c are 0.
  • a, b, and c are 1 and d is 0.
  • a, b, and d are 1 and c is 0.
  • a, c, and d are 1 and b is 0. In some embodiments, b and c are 1 and a and d are 0. In some embodiments, b and d are 1 and a and c are 0. In some embodiments, b, c, and d are 1 and a is 0. In some embodiments, c and d are 1 and a and b are 0. In some embodiments, a, b, c, and d are 1.
  • At least one of the pair of sulfur atoms is the sulfur atom corresponding to (e.g., the sulfur atom of) a hinge cysteine of SEQ ID NO: 4 or SEQ ID NO: 33, i.e., Cys10 and/or Cys13.
  • the pair of sulfur atoms are the sulfur atoms corresponding to (e.g., the sulfur atoms of) Cys10 and Cys13 in SEQ ID NO: 4 or SEQ ID NO: 33.
  • the pair of sulfur atoms include one sulfur atom of a cysteine from each E, i.e., L-A along with the sulfur atoms to which it is attached forms a bridge between two Fc domains (e.g., two Fc domains including the sequence of SEQ ID NO: 4 or SEQ ID NO: 33).
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 4 or SEQ ID NO: 33 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 4 or SEQ ID NO: 33 from another E.
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 4 or SEQ ID NO: 33 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 4 or SEQ ID NO: 33 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 4 or SEQ ID NO: 33 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 4 or SEQ ID NO: 33 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 4 or SEQ ID NO: 33 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 4 or SEQ ID NO: 33 from another E.
  • the conjugate has the structure: wherein each of a and b is, independently, 0 or 1 and wherein when a or b is 0, the two sulfur atoms form a disulfide bond.
  • a is 1 and b is 0.
  • a is 0 and b is 1.
  • a and b are 1.
  • at least one of the pair of sulfur atoms is the sulfur atom corresponding to (e.g., the sulfur atom of) a hinge cysteine of SEQ ID NO: 8, i.e., Cys10 and/or Cys13.
  • the pair of sulfur atoms are the sulfur atoms corresponding to (e.g., the sulfur atoms of) Cys10 and Cys13 in SEQ ID NO: 8.
  • the pair of sulfur atoms include one sulfur atom of a cysteine from each E, i.e., L-A along with the sulfur atoms to which it is attached forms a bridge between two Fc domains (e.g., two Fc domains including the sequence of SEQ ID NO: 8).
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 8 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 8 from another E.
  • the pair of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 8 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 8 from another E.
  • the pairs of sulfur atoms are the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 8 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys10 of SEQ ID NO: 8 from another E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 8 from one E and the sulfur atom corresponding to (e.g., the sulfur atom of) Cys13 of SEQ ID NO: 8 from another E.
  • the conjugate has the structure: wherein each of a and b is, independently, 0 or 1 and wherein when a or b is 0, the two sulfur atoms form a disulfide bond. In some embodiments, a is 1 and b is 0. In some embodiments, a is 0 and b is 1. In some embodiments, a and b are 1. In some embodiments, the conjugate has the structure: wherein each of a and b is, independently, 0 or 1 and wherein when a or b is 0, the two sulfur atoms form a disulfide bond. In some embodiments, a is 1 and b is 0. In some embodiments, a is 0 and b is 1. In some embodiments, a and b are 1.
  • the conjugate has the structure: wherein each of a and b is, independently, 0 or 1 and wherein when a or b is 0, the two sulfur atoms form a disulfide bond. In some embodiments, a is 1 and b is 0. In some embodiments, a is 0 and b is 1. In some embodiments, a and b are 1. In some embodiments, the conjugate has the structure: wherein each of a and b is, independently, 0 or 1 and wherein when a or b is 0, the sulfur atoms is a thiol. In some embodiments, a is 1 and b is 0. In some embodiments, a is 0 and b is 1. In some embodiments, a and b are 1.
  • the nitrogen atom is the nitrogen of a surface exposed lysine, e.g., the nitrogen atom corresponding to (e.g., the nitrogen atom of) Lys35, Lys63, Lys77, Lys79, Lys106, Lys123, Lys129, Lys181, Lys203, Lys228, or Lys236 of SEQ ID NO: 10 or SEQ ID NO: 11.
  • the nitrogen atom is the nitrogen atom corresponding to (e.g., the nitrogen atom of) Lys65, Lys79, Lys108, Lys230, and/or Lys238 of SEQ ID NO: 10 or SEQ ID NO: 11.
  • the conjugate has the structure: wherein each of a, b, c, d, and e is, independently, 0 or 1 and wherein when a, b, c, d, or e is 0, the two nitrogen atom is NH2.
  • a is 1 and b, c, d, and e are 0.
  • b is 1 and a, c, d, and e are 0.
  • c is 1 and a, b, d, and e are 0.
  • d is 1 and a, b, c, and e are 0.
  • e is 1 and a, b, c, and d are 0.
  • a and b are 1 and c, d, and e are 0. In some embodiments, a and c are 1 and b, d, and e are 0. In some embodiments, a and d are 1 and b, c, and e are 0. In some embodiments, a and e are 1 and b, c, and d are 0. In some embodiments, b and c are 1 and a, d, and e are 0. In some embodiments, b and d are 1 and a, c, and e are 0. In some embodiments, b and e are 1 and a, c, and d are 0. In some embodiments, c and d are 1 and a, b, and e are 0. In some embodiments, c and d are 1 and a, b, and e are 0. In some embodiments, c and d are 1 and a, b, and e are 0.
  • c and e are 1 and a, b, and d are 0. In some embodiments, d and e are 1 and a, b, and c are 0. In some embodiments, a, b, and c are 1 and d and e are 0. In some embodiments, a, b, and d are 1 and c and e are 0. In some embodiments, a, b, and e are 1 and c and d are 0. In some embodiments, a, c, and d are 1 and b and e are 0. In some embodiments, a, c, and e are 1 and b and d are 0. In some embodiments, a, d, and e are 1 and b and d are 0. In some embodiments, a, d, and e are 1 and b and c are 0.
  • b, c, and d are 1 and a and e are 0. In some embodiments, b, d, and e are 1 and a and c are 0. In some embodiments, c, d, and e are 1 and a and b are 0. In some embodiments of the conjugates described herein, the conjugate forms a homodimer including an Fc domain. In some embodiments of the conjugates described herein, E homodimerizes with another E to form an Fc domain.
  • the invention features a conjugate described by formula (D-I): (D-I) wherein E includes an albumin protein (e.g., an albumin protein having the sequence of any one of SEQ ID NOs: 139-141), an albumin protein-binding peptide, or an Fc-binding peptide; L in each A 1 -L-A 2 is a linker independently covalently attached to a sulfur atom of a surface exposed cysteine or a nitrogen atom of a surface exposed lysine in E and to each of A 1 and A 2 ; n is 1; T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), and the squiggly line connected to the E indicates that each A 1 -L-A 2 is independently covalently attached to the sulfur atom of a solvent-exposed cysteine or the nitrogen atom of a solvent-exposed lysine in E, or a pharmaceutically
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • the invention features a conjugate described by formula (M-I):
  • (M-I) E includes an albumin protein (e.g., an albumin protein having the sequence of any one of SEQ ID NOs: 139-141), an albumin protein-binding peptide, or an Fc-binding peptide;
  • L in each L-A 1 is a linker independently covalently attached to a sulfur atom of a surface exposed cysteine or a nitrogen atom of a surface exposed lysine in E and to A 1 ;
  • n is 1;
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20); and the squiggly line connected to E indicates that each L-A 1 is independently covalently attached to the sulfur atom of the solvent-exposed cysteine or the nitrogen atom of the solvent-exposed lysine in E, or a pharmaceutically acceptable salt thereof.
  • each A 1 may be independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • each E includes an albumin protein having the sequence of any one of SEQ ID NOs: 139-141.
  • T is 1 and L-A is covalently attached to the sulfur atom corresponding to Cys34 of SEQ ID NO: 139.
  • the invention features an intermediate (Int) of Table 1.
  • intermediates include one or inhibitors of RSV F protein (e.g., Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof) and a linker (e.g., a PEG2-PEG20 linker) and may be used in the synthesis of a conjugate described herein.
  • linker e.g., a PEG2-PEG20 linker
  • Intermediates of Table 1 may be conjugated to, for example, an Fc domain or Fc domain monomer, albumin protein, albumin protein-binding peptide, or Fc-binding peptide (e.g., by way of a linker) by any suitable methods known to those of skill in the art, including any of the methods described or exemplified herein.
  • the conjugate (e.g., a conjugate described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) includes E, wherein E is an Fc domain monomer or an Fc domain (e.g., an Fc domain monomer or an Fc domain, each Fc domain monomer having, independently, the sequence of any one of SEQ ID NOs: 1-138).
  • one or more nitrogen atoms of one or more surface exposed lysine residues of E or one or more sulfur atoms of one or more surface exposed cysteines in E is covalently conjugated to a linker (e.g., a PEG2-PEG20 linker).
  • the linker conjugated to E may be functionalized such that it may react to form a covalent bond with any of the Ints described herein (e.g., an Int of Table 1).
  • E is conjugated to a linker functionalized with an azido group and the Int (e.g., an Int of Table 1) is functionalized with an alkyne group.
  • Conjugation (e.g., by click chemistry) of the linker-azido of E and linker-alkyne of the Int forms a conjugate of the invention, for example a conjugate described by any one of formulas (1), (2), (D- I)-(D-VII), or (M-I)-(M-VII).
  • E is conjugated to a linker functionalized with an alkyne group and the Int (e.g., an Int of Table 1) is functionalized with an azido group.
  • Conjugation (e.g., by click chemistry) of the linker-alkyne of E and the linker-azido of the Int forms a conjugate of the invention, for example a conjugate described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M- VII).
  • Table 1 Intermediates
  • the invention features a conjugate of Table 2.
  • Each conjugate of Table 2 corresponds to a conjugate of either formula (M-I) or formula (D-I), as indicated.
  • Conjugates of Table 2 include conjugates formed by the covalent reaction of an Int of Table 1 with a linker which is in turn conjugated to E (e.g., an Fc domain monomer, an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide).
  • the reactive moiety of the Int reacts with a corresponding reactive group (e.g., an alkyne or azido group) of a linker (represented by L’) covalently attached to E, such that an Int of Table 1 is covalently attached to E.
  • L’ corresponds to the remainder of L as defined in (M-I) or (D-I) (e.g., L’ is a linker that covalently joins the Int and E).
  • L’ may include a triazole (formed by the click chemistry reaction between the Int and a linker conjugated to E) and a linker (e.g., a PEG2-PEG20 linker) which in turn is conjugated to an amino acid side chain of E.
  • n is 1 or 2.
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1- 138), an albumin protein (e.g., an albumin protein having the sequence of any one of SEQ ID NOs: 139- 141), an albumin protein-binding peptide, or an Fc-binding peptide.
  • each E includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138), and the Fc domain monomers dimerize to form and Fc domain.
  • T is an integer from 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20).
  • the disclosure also provides a population of any of the conjugates of Table 2 wherein the average value of T is 1 to 20 (e.g., the average value of T is 1 to 2, 1 to 3, 1 to 4, 1 to 5, 5 to 10, 10 to 15, or 15 to 20).
  • the average value of T is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.
  • the squiggly line in the conjugates of Table 2 indicates that each L’-Int is covalently attached to an amino acid side chain in E (e.g., the nitrogen atom of a surface exposed lysine or the sulfur atom of a surface exposed cysteine in E), or a pharmaceutically acceptable salt thereof.
  • E e.g., the nitrogen atom of a surface exposed lysine or the sulfur atom of a surface exposed cysteine in E
  • Table 2 Conjugates Corresponding to Intermediates of Table 1
  • each E includes an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138. In other embodiments, each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 63 or SEQ ID NO: 64. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 63 or SEQ ID NO: 64. In other embodiments, each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 67 or SEQ ID NO: 68. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 67 or SEQ ID NO: 68.
  • each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 72 or SEQ ID NO: 73. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 72 or SEQ ID NO: 73. In other embodiments, each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 76 or SEQ ID NO: 77. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 76 or SEQ ID NO: 77.
  • each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 81 or SEQ ID NO: 82. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 81 or SEQ ID NO: 82. In other embodiments, each E includes an Fc domain monomer having a sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 85 or SEQ ID NO: 86. In other embodiments, each E includes an Fc domain monomer having the amino acid sequence of SEQ ID NO: 85 or SEQ ID NO: 86.
  • the invention features a conjugate including (i) a first moiety, A 1 ; (ii) a second moiety, A 2 ; (iii) an Fc domain monomer or an Fc domain; and (iv) a linker covalently attached to A 1 and A 2 , and to the Fc domain monomer or the Fc domain; wherein each A 1 and each A 2 is independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • the invention features a conjugate including (i) a first moiety, Int; (ii) an Fc domain monomer or an Fc domain; and (iv) a linker covalently attached to Int, and to the Fc domain monomer or the Fc domain; wherein each Int is independently selected from any one of the intermediates of Table 1.
  • the invention features a conjugate including (i) a first moiety, A 1 ; (ii) a second moiety, A 2 ; (iii) an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide; and (iv) a linker covalently attached to A 1 and A 2 , and to the Fc domain monomer or the Fc domain; wherein each A 1 and each A 2 is independently selected from a structure described by any one of formulas (A-I)-(A-VI)
  • the invention features a conjugate described by formula (D-I): (D-I) wherein each A 1 and each A 2 is independently described by formula (A-I)-(A-VI); each E independently includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138), an albumin protein (e.g., an albumin protein having the sequence of any one of SEQ ID NOs:
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • the conjugate is described by formula (D-II): (D-II) or a pharmaceutically acceptable salt thereof.
  • conjugate is described by formula (D-II-1): (D-II-1) wherein R7 and R8 are each independently selected from OH, halogen, nitrile, nitro, optionally substituted amine, optionally substituted imine, optionally substituted C 1 -C 20 alkamino, optionally substituted sulfhydryl, optionally substituted carboxyl, optionally substituted cyano, optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 alkenyl, optionally substituted C 3 -C 20 cycloalkenyl, optionally substituted C 2 -C 20 alkynyl, optionally substituted C 5 -C 20 aryl, optionally substituted C 2 -C 15 heteroaryl, and optionally substituted C 1 -C 20 alkoxy; or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-II-2): (D-II-2) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by the formula (D-II-3) (D-II-3) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by the formula (D-II-4): (D-II-4) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (D-II-5): (D-II-5) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-II-6): (D-II-6) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (D-II-7): (D-II-7) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-II-8): (D-II-8) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-II-9): (D-II-9) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by the formula (D-II-10): (D-II-10) or a pharmaceutical acceptable salt thereof.
  • the conjugate is described by formula (D-II-11): (D-II-11) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (D-II-12): (D-II-12) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-II-13): (D-II-13) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-II-14): -II-14) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-II-15): (D-II-15) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-II-16): (D-II-16) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-II-17): (D-II-17) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-III): (D-III) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-III-1): (D-III-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-III-2): (D-III-2) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-III-3): (D-III-3) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each U 2 is an optionally substituted C1-C6 alkylene (e.g., C1, C2, C3, C4, C5, or C6 alkylene).
  • each U 3 is described by: , wherein Ub is C or O; and U4 is selected from amino, optionally substituted amine, optionally substituted imine, optionally substituted C 1 -C 20 alkamino,optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 5 -C 15 aryl, optionally substituted C 3 -C 15 heteroaryl, and a bond.
  • each U 3 is described by: In some embodiments, Ua is N. In some embodiments, Ua is CH. In some embodiments, p is 1, 2, or 3. In some emboidments, p is 1 or 2. In some embodiments, Ua is N and p is 1 or 2. In some embodiments, Ua is CH and p is 1, 2, or 3. In some embodiments, the conjugate is described by formula (D-IV-1): (D-IV-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-2): (D-IV-2) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (D-IV-3): (D-IV-3) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (D-IV-4): (D-IV-4) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-5): (D-IV-5) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-6): (D-IV-6) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-7): (D-IV-7) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-8): (D-IV-8) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-9): (D-IV-9) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-10): (D-IV-10) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-11): (D-IV-11) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-12): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-13): (D-IV-13) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-14): (D-IV-14) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-15): (D-IV-15) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-16): (D-IV-16) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-17): (D-IV-17) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-18): ; (D-IV-18) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-19): (D-IV-19) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-20): (D-IV-20) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-21): (D-IV-21) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-22): (D-IV-22) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-23): (D-IV-23) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-24): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-25): (D-IV-25) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-26): (D-IV-26) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-27): (D-IV-27) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-28): (D-IV-28) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-29): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-30): (D-IV-30) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-31): (D-IV-31) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-32): (D-IV-32) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-IV-33): (D-IV-33) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-IV-34): (D-IV-34) wherein L’ is the remainder of L, and y 1 and y 2 are each independently an integer from 1-20 (e.g., y 1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V): or a pharmaceutically acceptable salt thereof.
  • U 3 is an optionally substituted C1-C6 alkyl (e.g., -(CH 2 )4, -(CH 2 )3CN, -(CH 2 )4F, -(CH 2 )4OH, -(CH 2 )2SO2Me, -(CH 2 )3SO2CH 2 Me, or -(CH 2 )3SO2Me).
  • the conjugate is described by formula (D-V-1): (D-V-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-2): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-3): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-4): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-5): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-6): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-7): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-8): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-9): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-10): (D-V-10) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-11): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-12): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-13): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-14): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-15): (D-V-15) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-16): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-17): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-18): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-19): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-20): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-V-21): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-22): (D-V-22) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-V-23): (D-V-23) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-1): (D-VI-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VI-2): (D-VI-2) or a pharmaceutically acceptable salt thereof.
  • M4 is an optionally substituted C1-C6 alkylene (e.g., -CH 2 -, -CH 2 CH 2 -, or -CH 2 CH 2 CH 2 -).
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-3): (D-VI-3) or a pharmaceutically acceptable salt thereof.
  • M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-4): (D-VI-4) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-5): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-6): (D-VI-6) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-7): (D-VI-7) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-8): (D-VI-8) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-9): (D-VI-9) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-10): (D-VI-10) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-11): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-12): (D-VI-12) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-13): wherein L’ is the remainder of L, and y 1 and y 2 are each independently an integer from 1-20 (e.g., y 1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-14): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y 2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-15): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-16): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-17): (D-VI-17) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-18): (D-VI-18) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-19): (D-VI-19) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-20): (D-VI-20) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-21): (D-VI-21) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-22): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-23): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-24): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-25): (D-VI-25) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-26): (D-VI-26) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-27): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-28): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-29): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-30): (D-VI-30) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-31): (D-VI-31) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (D-VI-32): (D-VI-32) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VI-33): (D-VI-33) or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • M3 is absent
  • W is a C 2 -C 20 heterocycloalkyl (e.g., a piperidine)
  • M 4 is a C 1 -C 20 alkylene (e.g., -CH 2 CH 2 -).
  • M3 is absent, W is absent, and M4 is a C 1 -C 20 alkylene (e.g., -CH 2 CH 2 CH 2 -).
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-1): (D-VII-1) or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-2): (D-VII-2) or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-3): (D-VII-3) or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-4): (D-VII-4) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-5): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-6): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-7): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-8): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-9): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-10): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-11): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-12): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-13): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-14): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-15): In some embodiments, the conjugate is described by formula (D-VII-16): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof. In some embodiments, L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-17): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-18): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-19): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-20): (D-VII-20) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-21): (D-VII-21) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-22): (D-VII-22) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-23): (D-VII-23) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-24): (D-VII-24) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-25): (D-VII-25) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-26): (D-VII-26) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-27): (D-VII-27) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-28): (D-VII-28) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-29): (D-VII-29) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-30): (D-VII-30) or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-31): (D-VII-31) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-32): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-33): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-34): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-35): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-36): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-37): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y 2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-38): (D-VII-38) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-39): (D-VII-39) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-40): (D-VII-40) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-41): (D-VII-41) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-42): (D-VII-42) or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-43): (D-VII-43) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-44): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-45): (D-VII-45) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-46): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-47): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-48): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-49): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y 2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-50): (D-VII-50) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-51): (D-VII-51) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-52): (D-VII-52) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-53): (D-VII-53) wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (D-VII-54): or a pharmaceutically acceptable salt thereof.
  • Rz is NH2.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (D-VII-55): or a pharmaceutically acceptable salt thereof.
  • Rz is NH2.
  • the conjugate is described by formula (D-VII-56): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (D-VII-57): wherein L’ is the remainder of L, and y1 and y2 are each independently an integer from 1-20 (e.g., y1 and y2 are each independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • L or L’ includes one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene, optionally substituted C 2 -C 20 alkenylene, optionally substituted C 2 -C 20 heteroalkenylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene, optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycloalkynylene, optionally substituted C 5 -C 15 arylene, optionally substituted C 2 -C 15 heteroarylene, O, S, NR
  • the backbone of L or L’ consists of one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene, optionally substituted C 2 -C 20 alkenylene, optionally substituted C 2 -C 20 heteroalkenylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene, optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycloalkynylene, optionally substituted C 5 -C 15 arylene, optionally substituted C 2 -C 15 heteroarylene,
  • L or L’ is oxo substituted.
  • the backbone of L or L’ includes no more than 250 atoms.
  • L or L’ is capable of forming an amide, a carbamate, a sulfonyl, or a urea linkage.
  • L or L’ is a bond.
  • L or L’ is an atom.
  • L C is described by formula G C1 -(Z C1 )g3-(Y C1 )h3-(Z C2
  • optionally substituted includes substitution with a polyethylene glycol (PEG).
  • PEG polyethylene glycol
  • a PEG has a repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5- PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60-PEG70, PEG70-PEG80, PEG80- PEG90, PEG90-PEG100).
  • L C may have two points of attachment to the Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide (e.g., two G C2 ).
  • L includes a polyethylene glycol (PEG) linker.
  • a PEG linker includes a linker having the repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol linker may covalently join a RSV F protein inhibitor and E (e.g., in a conjugate of any one of formulas (M-I)-(M-IV)).
  • a polyethlylene glycol linker may covalently join a first RSV F protein inhibitor and a second RSV F protein inhibitor (e.g., in a conjugate of any one of formulas (D-I)-(D-VII)).
  • a polyethylene glycol linker may covalently joing a RSV F protein inhibitor dimer and E (e.g., in a conjugate of any one of formulas (D-I)-(D-VII)).
  • a polyethylene glycol linker may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5-PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60-PEG70, PEG70-PEG80, PEG80-PEG90, PEG90-PEG100).
  • L c includes a PEG linker, where L C is covalently attached to each of Q i and E.
  • Linkers of formula (D-L-I) that may be used in conjugates described herein include, but are not limited to
  • Linkers of the formula (D-L-I) may also include any of
  • each E independently includes an Fc domain monomer (e.g., an Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138), an albumin protein (e.g., an albumin protein having the sequence of any one of SEQ ID NOs: 139-141), an albumin protein-binding peptide, or an Fc- binding peptide;
  • n is 1 or 2;
  • T is an integer from 1 to 20 (e.g., T is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20);
  • L is a linker covalently attached to each of E and A 1 , or a pharmaceutically acceptable salt thereof.
  • each A 1 may be independently selected from a structure described by any one of formulas (A-I)-(A-VI).
  • the conjugate is described by formula (M-II): (M-II) or a pharmaceutically acceptable salt thereof.
  • conjugate is described by formula (M-II-1): (M-II-1) wherein R7 and R8 are each independently selected from OH, halogen, nitrile, nitro, optionally substituted amine, optionally substituted imine, optionally substituted C 1 -C 20 alkamino, optionally substituted sulfhydryl, optionally substituted carboxyl, optionally substituted cyano, optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 alkenyl, optionally substituted C 3 -C 20 cycloalkenyl, optionally substituted C 2 -C 20 alkynyl, optionally substituted C 5 -C 20 aryl, optionally substituted C 2 -C 15 heteroaryl, and optionally substituted C 1 -C 20 alkoxy; or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-II-2): (M-II-2) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by the formula (M-II-3) (M-II-3) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by the formula (M-II-4): (M-II-4) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (M-II-5): (M-II-5) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-II-6): (M-II-6) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (M-II-7): (M-II-7) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-II-8): (M-II-8) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-II-9): (M-II-9) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof. In some embodiments, L’ is a nitrogen atom. In some embodiments, the conjugate is described by the formula (M-II-10): (M-II-10) or a pharmaceutical acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-II-11): (M-II-11) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by the formula (M-II-12): (M-II-12) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-II-13): (M-II-13) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-II-14): (M-II-14) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-II-15): (M-II-15) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-II-16): (M-II-16) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-II-17): (M-II-17) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-III): (M-III) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-III-1): (M-III-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-III-2): (M-III-2) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-III-3): (M-III-3) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV): , (M-IV) or a pharmaceutically acceptable salt thereof.
  • U 2 is an optionally substituted C1- C6 alkylene (e.g., C1, C2, C3, C4, C5, or C6 alkylene).
  • U 3 is described by: , wherein Ub is C or O; and U4 is selected from amino, optionally substituted amine, optionally substituted imine, optionally substituted C 1 -C 20 alkamino,optionally substituted C 1 -C 20 alkyl, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 5 -C 15 aryl, optionally substituted C 3 -C 15 heteroaryl, and a bond.
  • U 3 is described by: In some embodiments, Ua is N. In some embodiments, Ua is CH. In some embodiments, p is 1, 2, or 3. In some emboidments, p is 1 or 2. In some embodiments, Ua is N and p is 1 or 2. In some embodiments, Ua is CH and p is 1, 2, or 3.
  • the conjugate is described by formula (M-IV-1): (M-IV-1) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-IV-2): (M-IV-2) or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-IV-3): (M-IV-3) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-4): (M-IV-4) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-5): (M-IV-5) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-6): (M-IV-6) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-7): (M-IV-7) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-8): wherein U 2 is an optionally substituted C1-C6 alkylene (e.g., C1, C2, C3, C4, C5, or C6 alkylene), or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-9): (M-IV-9) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-10): (M-IV-10) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-11): (M-IV-11) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-12): (M-IV-12) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-13): (M-IV-13) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-14): (M-IV-14) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-15): (M-IV-15) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-16): (M-IV-16) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-17): (M-IV-17) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-18): (M-IV-18) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-19): (M-IV-19) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-20): (M-IV-20) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-21): (M-IV-21) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-22): (M-IV-22) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-23): (M-IV-23) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-24): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-25): (M-IV-25) wherein U 2 is an optionally substituted C1-C6 alkyl (e.g., C1, C2, C3, C4, C5, or C6 alkyl), or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-26): (M-IV-26) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-27): (M-IV-27) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-28): (M-IV-28) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-29): (M-IV-29) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-30): (M-IV-30) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-31): (M-IV-31) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-32): (M-IV-32) wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-IV-33): (M-IV-33) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-IV-34): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V): or a pharmaceutically acceptable salt thereof.
  • U 3 is an optionally substituted C1-C6 alkyl (e.g., -(CH 2 )4, -(CH 2 )3CN, -(CH 2 )4F, -(CH 2 )4OH, -(CH 2 )2SO2Me, -(CH 2 )3SO2CH 2 Me, or -(CH 2 )3SO2Me).
  • the conjugate is described by formula (M-V-1): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-2): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-3): (M-V-3) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-4): (M-V-4) wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-5): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-6): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-7): (M-V-7) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-8): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-9): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-10): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-11): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-12): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-13): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-14): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof. In some embodiments, L’ is a nitrogen atom. In some embodiments, the conjugate is described by formula (M-V-15): or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-V-16): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-17): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-18): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-19): or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-V-20): or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-V-21): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-V-22): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-V-23): wherein L’ is the remainder of L, and y1 is an integer from 1-20 (e.g., y1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VI-1): (M-VI-1) or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VI-2): or a pharmaceutically acceptable salt thereof.
  • M4 is an optionally substituted C1-C6 alkylene (e.g., -CH 2 -, -CH 2 CH 2 -, or -CH 2 CH 2 CH 2 -).
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-3): or a pharmaceutically acceptable salt thereof.
  • M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-4): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-5): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-6): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-7): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-8): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-9): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-10): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-11): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-12): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-13): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-14): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-15): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof. In some embodiments, L’ is a nitrogen atom. In some embodiments, the conjugate is described by formula (M-VI-16): or a pharmaceutically acceptable salt thereof. In preferred embodiments each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-17): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-18): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-19): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-20): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-21): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-22): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-23): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-24): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-25): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-26): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-27): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-28): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-29): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VI-30): or a pharmaceutically acceptable salt thereof.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-31): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1 or 2.
  • the conjugate is described by formula (M-VI-32): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • each M 1 is H (e.g., the corresponding phenyl ring is unsubstituted).
  • each M 1 is a C 1 -C 3 alkyl (e.g., - CH 3 ) and b is 1 or 2.
  • M3 is absent
  • W is a C 2 -C 20 heterocycloalkyl (e.g., a piperidine)
  • M4 is a C 1 -C 20 alkylene (e.g., -CH 2 CH 2 -).
  • M3 is absent
  • W is absent
  • M4 is a C 1 -C 20 alkylene (e.g., -CH 2 CH 2 CH 2 -).
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-1): or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-2): or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-3): or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-4): or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-VII-5): or a pharmaceutically acceptable salt thereof. In some embodiments, the conjugate is described by formula (M-VII-6): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof. In some embodiments, L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-7): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-8): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-9): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-10): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-11): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-12): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-13): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-14): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-15): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-16): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-17): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-18): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-19): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-20): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-21): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-22): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-23): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-24): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-25): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-26): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-27): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-28): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-29): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-30): or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-31): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-32): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-33): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-34): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-35): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-36): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-37): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-38): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-39): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-40): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-41): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-42): or a pharmaceutically acceptable salt thereof.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-43): In some embodiments, the conjugate is described by formula (M-VII-44): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-45): (M-VII-45) wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-46): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-47): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-48): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-49): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-50): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-51): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-52): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-53): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • the conjugate is described by formula (M-VII-54): or a pharmaceutically acceptable salt thereof.
  • Rz is NH2.
  • each K 1 is H (e.g., the corresponding phenyl is unsubstituted).
  • K 2 is a C 1 -C 3 alkyl (e.g., -CH 3 ) and b is 1.
  • the conjugate is described by formula (M-VII-55): or a pharmaceutically acceptable salt thereof.
  • Rz is NH2.
  • the conjugate is described by formula (M-VII-56): or a pharmaceutically acceptable salt thereof.
  • the conjugate is described by formula (M-VII-57): wherein L’ is the remainder of L, and each y1 are independently an integer from 1-20 (e.g., each y1 are independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • L’ is a nitrogen atom.
  • L or L’ includes one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene, optionally substituted C 2 -C 20 alkenylene, optionally substituted C 2 -C 20 heteroalke ⁇ nylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene, optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycloalkynylene, optionally substituted C 5 -C 15 arylene, optionally substituted
  • the backbone of L or L’ consists of one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene, optionally substituted C 2 -C 20 alkenylene, optionally substituted C 2 -C 20 heteroalkenylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene, optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycloalkynylene, optionally substituted C 5 -C 15 arylene, optionally substituted C 2 -C 15 heteroarylene,
  • L or L’ is oxo substituted.
  • the backbone of L or L’ includes no more than 250 atoms.
  • L or L’ is capable of forming an amide, a carbamate, a sulfonyl, or a urea linkage.
  • L or L’ is a bond.
  • L or L’ is an atom.
  • L’ is a nitrogen atom.
  • each L is described by formula (M-L-I): J 1 -(Q 1 ) g -(T 1 ) h -(Q 2 ) i -(T 2 ) j -(Q 3 ) k -(T 3 ) l -(Q 4 ) m -(T 4 ) n -(Q 5 ) o -J 2 wherein: J 1 is a bond attached to A 1 ; J 2 is a bond attached to E or a functional group capable of reacting with a functional group conjugated to E (e.g., maleimide and cysteine, amine and activated carboxylic acid, thiol and maleimide, activated sulfonic acid and amine, isocyanate and amine, azide and alkyne, and alkene and tetrazine); each of Q 1 , Q 2 , Q 3 , Q 4 , and Q 5 is, independently, optionally substituted C 1 -C
  • optionally substituted includes substitution with a polyethylene glycol (PEG).
  • PEG polyethylene glycol
  • a PEG has a repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5- PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60-PEG70, PEG70-PEG80, PEG80- PEG90, PEG90-PEG100).
  • J 2 may have two points of attachment to the Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide (e.g., two J 2 ).
  • L is wherein d is an integer from 1 to 20 (e.g., d is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). In some embodiments, L is
  • each R8 is independently selected from H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 1 -C 20 alkylene, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 5 -C 15 aryl, and optionally substituted C 2 -C 15 heteroaryl; each R9 is independently selected from optionally substituted C 1 -C 20 alkylene, optionally substituted C 3 -C 20 cycloalkyl, optionally substituted C 2 -C 20 heterocycloalkyl, optionally substituted C 5 -C 15 aryl, and optionally substituted C 2 -C 15 heteroaryl; and each of d, e, y1, and x1 is, independently, an integer from 1 to 26 (e.g., d is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or 26).
  • L includes (e.g., a portion of L that joins A 1 and E includes): , .
  • L includes a polyethylene glycol (PEG) linker.
  • PEG linker includes a linker having the repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol linker may covalently join a RSV F protein inhibitor and E (e.g., in a conjugate of any one of formulas ).
  • a polyethlylene glycol linker may covalently join a first RSV F protein inhibitor and a second RSV F protein inhibitor (e.g., in a conjugate of any one of formulas ).
  • a polyethylene glycol linker may covalently join a RSV F protein inhibitor dimer and E (e.g., in a conjugate of any one of formulas).
  • a polyethylene glycol linker may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5-PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60- PEG70, PEG70-PEG80, PEG80-PEG90, PEG90-PEG100).
  • L c includes a PEG linker, where L C is covalently attached to each of Q i and E.
  • L is covalently attached to the nitrogen atom of a surface exposed lysine of E or L is covalently attached to the sulfur atom of a surface exposed cysteine of E.
  • E is an Fc domain monomer.
  • n is 2 and each E dimerizes to form an Fc domain.
  • n 2
  • each E is an Fc domain monomer, each E dimerizes to form an Fc domain, and the conjugate is described by formula (D-I-1): (D-I-1) wherein J is an Fc domain; and T is an integer from 1 to 20 (e.g., T is 1 ,2 ,3 ,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • n 2
  • each E is an Fc domain monomer, each E dimerizes to form an Fc domain, and the conjugate is described by formula (M-I-1): (M-I-1) wherein J is an Fc domain; and T is an integer from 1 to 20 (e.g., T is 1 ,2 ,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), or a pharmaceutically acceptable salt thereof.
  • E has the sequence of any one of SEQ ID NOs: 1-138.
  • E is an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide.
  • n is 1.
  • E is an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide
  • n is 1
  • E is an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide and the conjugate is described by formula (D-I-2): (D-I-2) wherein E is an albumin protein, an albumin protein-binding peptide, or Fc-binding peptide
  • T is an integer from 1 to 20, or a pharmaceutically acceptable salt thereof.
  • n 1, E is an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide, and the conjugate is described by formula (M-I-2): (M-I-2) wherein E is an albumin protein, an albumin protein-binding peptide, or an Fc-binding peptide; and T is an integer from 1 to 20, or a pharmaceutically acceptable salt thereof.
  • E is an albumin protein having the sequence of any one of SEQ ID NOs: 139-141.
  • T is 1, 2, 3, 4, or 5.
  • the invention provides a population of conjugates having the structure of any of the conjugates described herein (e.g., a population of conjugates having the formula of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)), wherein the average value of T is 1 to 20 (e.g., the average value of T is 1 to 2, 1 to 3, 1 to 4, 1 to 5, 5 to 10, 10 to 15, or 15 to 20). In some embodiments, the average value of T is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.
  • the invention provides a pharmaceutical composition including any of the conjugates described herein (e.g., a conjugate of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M- I)-(M-VII)), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
  • a pharmaceutical composition including any of the conjugates described herein (e.g., a conjugate of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M- I)-(M-VII)), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.
  • the invention provides a method for the treatment of a subject having a viral infection or presumed to have a viral infection, the method including administering to the subject an effective amount of any of the conjugates or compositions described herein (e.g., a conjugate of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • an effective amount of any of the conjugates or compositions described herein e.g., a conjugate of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • the invention provides a method for the prophylactic treatment of a viral infection in a subject in need thereof, the method including administering to the subject an effective amount of any of the conjugates or compositions described herein (e.g., a conjugate of any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • the viral infection is caused by RSV.
  • the viral infection is RSV A or RSV B.
  • the subject is immunocompromised.
  • the subject has been diagnosed with humoral immune deficiency, T cell deficiency, neutropenia, asplenia, or complement deficiency.
  • the subject is being treated or is about to be treated with an immunosuppresive therapy.
  • the subject has been diagnosed with a disease which causes immunosuppression.
  • the disease is cancer or acquired immunodeficiency syndrome.
  • the cancer is leukemia, lymphoma, or multiple myeloma.
  • the subject has undergone or is about to undergo hematopoietic stem cell transplantation.
  • the subject has undergone or is about to undergo an organ transplant.
  • the subject is less than 60 months old. In some embodiments, the subject is less than 24 months old. In some embodiments, wherein the subject is a premature infant.
  • the conjugate of composition is administered intramuscularly, intravenously, intradermally, intraarterially, intraperitoneally, intralesionally, intracranially, intraarticularly, intraprostatically, intrapleurally, intratracheally, intranasally, intravitreally, intravaginally, intrarectally, topically, intratumorally, peritoneally, subcutaneously, subconjunctival, intravesicularlly, mucosally, intrapericardially, intraumbilically, intraocularally, orally, locally, by inhalation, by injection, or by infusion.
  • the subject is treated with a second therapeutic agent.
  • the second therapeutic agent is an antiviral agent.
  • the second therapeutic agent is a viral vaccine.
  • the viral vaccine elicits an immune response in the subject against RSV (e.g., RSV A or RSV B).
  • an Fc-domain-containing composition may be substituted for an Fc domain and an Fc-domain-monomer-containing composition may be substituted for an Fc domain monomer in any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII) (e.g., any one of formulas (1), (2), (D-I), (D-II), (D-II-1), (D-II-2), (D-II-3), (D-II-4), (D-II-5), (D-II-6), (D-II-7), (D-II-8), (D-II-9), (D-II-10), (D-II-11), (D-II-12), (D-II-13), (D-
  • any of the formulas described herein e.g., any one of formulas (1), (2),(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • E is an Fc-domain-monomer-containing composition.
  • any of the formulas described herein e.g., any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • E is an Fc-domain- containing composition.
  • the Fc-domain-containing composition is an antibody or an antibody fragment.
  • An antibody may include any form of immunoglobulin, heavy chain antibody, light chain antibody, LRR-based antibody, or other protein scaffold with antibody-like properties, as well as any other immunological binding moiety known in the art, including antibody fragments (e.g., a Fab, Fab', Fab’2, F(ab')2, Fd, Fv, Feb, scFv, or SMIP).
  • antibody fragments e.g., a Fab, Fab', Fab’2, F(ab')2, Fd, Fv, Feb, scFv, or SMIP.
  • the subunit structures and three-dimensional configurations of different classes of antibodies are known in the art.
  • An antibody fragment may include a binding moiety that includes a portion derived from or having significant homology to an antibody, such as the antigen- determining region of an antibody.
  • Exemplary antibody fragments include Fab, Fab', Fab’2, F(ab')2, Fd, Fv, Feb, scFv, and SMIP.
  • the antibody or antibody fragment is a human, mouse, camelid (e.g., llama, alpaca, or camel), goat, sheep, rabbit, chicken, guinea pig, hamster, horse, or rat antibody or antibody fragment.
  • the antibody is an IgG, IgA, IgD, IgE, IgM, or intrabody.
  • the antibody fragment includes an scFv, sdAb, dAb, Fab, Fab', Fab'2, F(ab')2, Fd, Fv, Feb, or SMIP.
  • the Fc-domain-containing composition e.g., an antibody or antibody fragment
  • confers binding specificity to a one or more targets e.g., an antigen such as an antigen associated with RSV.
  • targets e.g., an antigen such as an antigen associated with RSV.
  • RSV targeting antibodies are known in the art, for example, as described in Gilman et al. Sci. Immunol.1(6), (2006), which is incorporated herein by reference in its entirety.
  • the one or more targets (e.g., an antigen) bound by the Fc-domain- containing composition is a viral (e.g., RSV) protein such as RSV F protein.
  • the antibody or antibody fragment recognizes a viral surface antigen.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 1.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 1.
  • E includes the amino acid sequence of SEQ ID NO: 2.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 2.
  • E includes the amino acid sequence of SEQ ID NO: 3.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 3.
  • E includes the amino acid sequence of SEQ ID NO: 4.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 4.
  • E includes the amino acid sequence of SEQ ID NO: 5.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 5.
  • E includes the amino acid sequence of SEQ ID NO: 6.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 6.
  • E includes the amino acid sequence of SEQ ID NO: 7.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 7.
  • E includes the amino acid sequence of SEQ ID NO: 8.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 8.
  • E includes the amino acid sequence of SEQ ID NO: 9.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 9.
  • E includes the amino acid sequence of SEQ ID NO: 10. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 10. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 11. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 11.
  • E includes the amino acid sequence of SEQ ID NO: 12. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 12. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 13. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 13.
  • E includes the amino acid sequence of SEQ ID NO: 14. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 14. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 15. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 15.
  • E includes the amino acid sequence of SEQ ID NO: 16. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 16. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 17. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 17.
  • E includes the amino acid sequence of SEQ ID NO: 18. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 18. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 19. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 19.
  • E includes the amino acid sequence of SEQ ID NO: 20. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 20. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 21. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 21.
  • E includes the amino acid sequence of SEQ ID NO: 22. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 22. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 23. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 23.
  • E includes the amino acid sequence of SEQ ID NO: 24. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 24. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 25. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 25.
  • E includes the amino acid sequence of SEQ ID NO: 26. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 26. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 27. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 27.
  • E includes the amino acid sequence of SEQ ID NO: 28. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 28. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 29. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 29.
  • E includes the amino acid sequence of SEQ ID NO: 30. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 30. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 31. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 31.
  • E includes the amino acid sequence of SEQ ID NO: 32. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 32. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 33. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 33.
  • E includes the amino acid sequence of SEQ ID NO: 34. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 34. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 35. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 35.
  • E includes the amino acid sequence of SEQ ID NO: 36. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 36. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 37. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 37.
  • E includes the amino acid sequence of SEQ ID NO: 38. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 38. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 39. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 39.
  • E includes the amino acid sequence of SEQ ID NO: 40. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 40. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 41. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 41.
  • E includes the amino acid sequence of SEQ ID NO: 42. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 42. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 43. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 43.
  • E includes the amino acid sequence of SEQ ID NO: 44. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 45. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 46. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 46.
  • E includes the amino acid sequence of SEQ ID NO: 47. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 47. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 48. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 48.
  • E includes the amino acid sequence of SEQ ID NO: 49. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 49. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 50. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 50.
  • E includes the amino acid sequence of SEQ ID NO: 51. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 51. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 52. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 52.
  • E includes the amino acid sequence of SEQ ID NO: 53. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 53. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 54. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 54.
  • E includes the amino acid sequence of SEQ ID NO: 55. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 55. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 56. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 56.
  • E includes the amino acid sequence of SEQ ID NO: 57.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 57.
  • E includes the amino acid sequence of SEQ ID NO: 58.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 58.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 59.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 59.
  • E includes the amino acid sequence of SEQ ID NO: 60. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 60. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 61. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 61.
  • E includes the amino acid sequence of SEQ ID NO: 62.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 62.
  • E includes the amino acid sequence of SEQ ID NO: 63.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 63.
  • E includes the amino acid sequence of SEQ ID NO: 64.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 64.
  • E includes the amino acid sequence of SEQ ID NO: 65.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 65.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 66.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 66.
  • E includes the amino acid sequence of SEQ ID NO: 67.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 67.
  • E includes the amino acid sequence of SEQ ID NO: 68.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 68.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 69.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 69.
  • E includes the amino acid sequence of SEQ ID NO: 70. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 70. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 71. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 71.
  • E includes the amino acid sequence of SEQ ID NO: 72. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 72. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 73. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 73.
  • E includes the amino acid sequence of SEQ ID NO: 74. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 74. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 75. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 75.
  • E includes the amino acid sequence of SEQ ID NO: 76.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 76.
  • E includes the amino acid sequence of SEQ ID NO: 77.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 77.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 78.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 78.
  • E includes the amino acid sequence of SEQ ID NO: 79. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 79. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 80. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 80.
  • E includes the amino acid sequence of SEQ ID NO: 81.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 81.
  • E includes the amino acid sequence of SEQ ID NO: 82.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 82.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 83.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 83.
  • E includes the amino acid sequence of SEQ ID NO: 84. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 84. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 85. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 85.
  • E includes the amino acid sequence of SEQ ID NO: 86.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 86.
  • E includes the amino acid sequence of SEQ ID NO: 87.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 87.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 88.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 88.
  • E includes the amino acid sequence of SEQ ID NO: 89. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 89. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 90. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 90.
  • E includes the amino acid sequence of SEQ ID NO: 91.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 91.
  • E includes the amino acid sequence of SEQ ID NO: 92.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 92.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 93.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 93.
  • E includes the amino acid sequence of SEQ ID NO: 94. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 94. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 95. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 95.
  • E includes the amino acid sequence of SEQ ID NO: 96.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 96.
  • E includes the amino acid sequence of SEQ ID NO: 97.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 97.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 98.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 98.
  • E includes the amino acid sequence of SEQ ID NO: 99. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 99. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 100. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 100.
  • E includes the amino acid sequence of SEQ ID NO: 101. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 101. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 102. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 102.
  • E includes the amino acid sequence of SEQ ID NO: 103.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 103.
  • E includes the amino acid sequence of SEQ ID NO: 104.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 104.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 105.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 105.
  • E includes the amino acid sequence of SEQ ID NO: 106.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 106.
  • E includes the amino acid sequence of SEQ ID NO: 107.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 107.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 108.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 108.
  • E includes the amino acid sequence of SEQ ID NO: 109. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 109. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 110. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 110.
  • E includes the amino acid sequence of SEQ ID NO: 111. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 111. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 112. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 112.
  • E includes the amino acid sequence of SEQ ID NO: 113.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 113.
  • E includes the amino acid sequence of SEQ ID NO: 114.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 114.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 115.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 115.
  • E includes the amino acid sequence of SEQ ID NO: 116.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 116.
  • E includes the amino acid sequence of SEQ ID NO: 117.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 117.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 118.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 118.
  • E includes the amino acid sequence of SEQ ID NO: 119. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 119. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 120. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 120.
  • E includes the amino acid sequence of SEQ ID NO: 121.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 121.
  • E includes the amino acid sequence of SEQ ID NO: 122.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 122.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 123.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 123.
  • E includes the amino acid sequence of SEQ ID NO: 124.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 124.
  • E includes the amino acid sequence of SEQ ID NO: 125.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 125.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 126.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 126.
  • E includes the amino acid sequence of SEQ ID NO: 127.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 127.
  • E includes the amino acid sequence of SEQ ID NO: 128.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 128.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 129.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 129.
  • E includes the amino acid sequence of SEQ ID NO: 130. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 130. In some embodiments of any of the aspects described herein, E (e.g., each E) includes the amino acid sequence of SEQ ID NO: 131. In some embodiments, E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 131.
  • E includes the amino acid sequence of SEQ ID NO: 132.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 132.
  • E includes the amino acid sequence of SEQ ID NO: 133.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 133.
  • E e.g., each E
  • E includes the amino acid sequence of SEQ ID NO: 134.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 134.
  • E includes the amino acid sequence of SEQ ID NO: 135.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 135.
  • E includes the amino acid sequence of SEQ ID NO: 136.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 136.
  • E includes the amino acid sequence of SEQ ID NO: 137.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 137.
  • E includes the amino acid sequence of SEQ ID NO: 138.
  • E includes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 138.
  • the Fc domain monomer e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138
  • the Fc domain monomer includes a triple mutation corresponding to M252Y/S254T/T256E (YTE).
  • an amino acid “corresponding to” a particular amino acid residue should be understood to include any amino acid residue that one of skill in the art would understand to align to the particular residue (e.g., of the particular sequence).
  • any one of SEQ ID NOs: 1-138 may be mutated to include a YTE mutation.
  • the Fc domain monomer e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138
  • LS double mutant corresponding to M428L/N434S
  • an amino acid “corresponding to” a particular amino acid residue should be understood to include any amino acid residue that one of skill in the art would understand to align to the particular residue (e.g., of the particular sequence).
  • any one of SEQ ID NOs: 1-138 may be mutated to include a LS mutation.
  • the Fc domain monomer e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138
  • the Fc domain monomer (e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138) includes a mutant corresponding to C220S.
  • an amino acid “corresponding to” a particular amino acid residue e.g., or a particular SEQ ID NO.
  • any one of SEQ ID NOs: 1-138 may be mutated to include a C220S mutation.
  • the Fc domain monomer (e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-95) includes a triple mutation corresponding to L309D/Q311H/N434S (DHS).
  • DHS L309D/Q311H/N434S
  • an amino acid “corresponding to” a particular amino acid residue should be understood to include any amino acid residue that one of skill in the art would understand to align to the particular residue (e.g., of the particular sequence).
  • any one of SEQ ID NOs: 1-95 may be mutated to include a DHS mutation.
  • an amino acid “corresponding to” a particular amino acid residue should be understood to include any amino acid residue that one of skill in the art would understand to align to the particular residue (e.g., of the particular sequence).
  • any one of SEQ ID NOs: 1-138 may be mutated to include an N434H mutation.
  • the Fc domain monomer (e.g., the Fc domain monomer having the sequence of any one of SEQ ID NOs: 1-138) is a fragment of the Fc domain monomer (e.g., a fragment of at least 25 (e.g., 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 or more), at least 50 (e.g., 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75 or more), at least 75 (e.g., 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86
  • one or more nitrogen atoms of one or more surface exposed lysine residues of E or one or more sulfur atoms of one or more surface exposed cysteines in E is covalently conjugated to a linker (e.g., a PEG 2 -PEG 20 linker).
  • the linker conjugated to E may be functionalized such that it may react to form a covalent bond with the L of any A 1 -L or any A 2 -L-A 1 described herein.
  • E is conjugated to a linker functionalized with an azido group and the L of A 1 -L or any A 2 -L-A 1 is functionalized with an alkyne group.
  • Conjugation e.g., by click chemistry
  • the linkner-azido of E and ther linker-alkyne of A 1 -L or A 2 -L-A 1 forms a conjugate of the invention, for example a conjugate described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M- VII).
  • E is conjugated to a linker functionalized with an alkyne group and L of an A 1 -L or of any A 2 -L-A 1 is functionalized with an azido group.
  • Conjugate e.g., by click chemistry
  • linker-alkyne of E and linker-azido of A 1 -L or of any A 2 -L-A 1 forms a conjugate of the invention, for example a conjugate described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII).
  • the squiggly line of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII) represents a covalent bond between the L of A 1 -L or A 2 -L- A 1 .
  • the squiggly line of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII) represents that one or more amino acid side chains of E (e.g., one or more nitrogen atoms of one or more surface exposed lysine residues of E or one or more sulfur atoms of one or more surface exposed cysteines in E) have been conjugated to a linker (e.g., a PEG2-PEG20 linker) wherein the linker has been functionalized with a reactive moiety, such that the reactive moiety forms a covalent bond with the L of any A 1 -L or any A 2 -L-A 1 described herein (e.g., by click chemistry between an azido functionalized linker and an alkyne functionalized linker, as described above).
  • a linker e.g., a PEG2-PEG20 linker
  • the conjugate is conjugate 1, or any regioisomer thereof, and the drug-to- antibody ratio (DAR) (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 2, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 3, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0. In some embodiments, the conjugate is conjugate 4, or any regioisomer thereof, and the drug-to- antibody ratio (DAR) (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • DAR drug-to- antibody ratio
  • the conjugate is conjugate 5, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 6, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 7, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 8, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 9, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0 between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 10, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 11, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 12, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 13, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0. In some embodiments, the conjugate is conjugate 14, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 15, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 16, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 17, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 18, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 19, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 20, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 21, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 22, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 23, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0. In some embodiments, the conjugate is conjugate 24, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 25, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0. In some embodiments, the conjugate is conjugate 26, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0. In some embodiments the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 27, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 28, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 29, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 30, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 31, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 32, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 33, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 34, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 35, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the conjugate is conjugate 36, or any regioisomer thereof, and the DAR (e.g., T) is between 0.5 and 10.0.
  • the DAR is between 0.5 and 2.0, between 2.0 and 4.0, between 4.0 and 6.0, between 6.0 and 8.0, or between 8.0 and 10.0.
  • the Fc domain monomer includes less than about 300 amino acid residues (e.g., less than about 300, less than about 295, less than about 290, less than about 285, less than about 280, less than about 275, less than about 270, less than about 265, less than about 260, less than about 255, less than about 250, less than about 245, less than about 240, less than about 235, less than about 230, less than about 225, or less than about 220 amino acid residues).
  • the Fc domain monomer is less than about 40 kDa (e.g., less than about 35kDa, less than about 30kDa, less than about 25kDa).
  • the Fc domain monomer includes at least 200 amino acid residues (e.g., at least 210, at least 220, at least 230, at least 240, at least 250, at least 260, at least 270, at least 280, at least 290, or at least 300 amino residues). In some embodiments, the Fc domain monomer is at least 20 kDa (e.g, at least 25 kDa, at least 30 kDa, or at least 35 kDa). In some embodiments, the Fc domain monomer includes 200 to 400 amino acid residues (e.g., 200 to 250, 250 to 300, 300 to 350, 350 to 400, 200 to 300, 250 to 350, or 300 to 400 amino acid residues).
  • the Fc domain monomer is 20 to 40 kDa (e.g., 20 to 25 kDa, 25 to 30 kDa, 35 to 40 kDa, 20 to 30 kDa, 25 to 35 kDa, or 30 to 40 KDa).
  • the Fc domain monomer includes an amino acid sequence at least 90% identical (e.g., at least 95%, at least 98%) to the sequence of any one of SEQ ID NOs: 1-138, or a region thereof.
  • the Fc domain monomer includes the amino acid sequence of any one of SEQ ID NOs: 1-138, or a region thereof.
  • the Fc domain monomer includes a region of any one of SEQ ID NOs: 1- 138, wherein the region includes positions 220, 252, 254, and 256.
  • the region includes at least 40 amino acid residues, at least 50 amino acid residues, at least 60 amino acid residues, at least 70 amino acids residues, at least 80 amino acids residues, at least 90 amino acid residues, at least 100 amino acid residues, at least 110 amino acid residues, at least 120 amino residues, at least 130 amino acid residues, at least 140 amino acid residues, at least 150 amino acid residues, at least 160 amino acid residues, at least 170 amino acid residues, at least 180 amino acid residues, at least 190 amino acid residues, or at least 200 amino acid residues.
  • the Fc domain includes a dimer of Fc domain monomers each independently selected from any one of the Fc domain monomers described herein, where the Fc domain is between about 50 kDa and about 70 kDa (e.g., about 51 kDa, about 52 kDa, about 53 kDa, about 54 kDa, about 55 kDa, about 56 kDa, about 57 kDa, about 58 kDa, about 59 kDa, about 60 kDa, about 61 kDa, about 62 kDa, about 63 kDa, about 64 kDa, about 65 kDa, about 66 kDa, about 67 kDa, about 68 kDa, or about 69 kDa) in mass.
  • the Fc domain is between about 50 kDa and about 70 kDa (e.g., about 51 kDa, about 52 kDa, about 53 kDa, about
  • the Fc domain monomer dimerizes (e.g., a homodimer or a heterodimer) to form an Fc domain.
  • the Fc domain is at least 40 kDa (e.g., at least 45 kDa, at least 50 kDa, at least 55 kDa, at least 60 kDa, at least 65 kDa, at least 70 kDa, at least 75 kDa, or at least 80 kDa) in mass.
  • the Fc domain is between 40 kDa and 80 kDa (e.g., between about 42 kDa and about 50 kDa, about 48 kDa and about 55 kDa, about 53 kDa about about 60 kDa, about 58 kDa and about 65 kDa, about 62 kDa and about 70 kDa, about 68 kDa and about 75 kDa, or about 72 kDa and about 80 kDa) in mass.
  • 40 kDa and 80 kDa e.g., between about 42 kDa and about 50 kDa, about 48 kDa and about 55 kDa, about 53 kDa about about 60 kDa, about 58 kDa and about 65 kDa, about 62 kDa and about 70 kDa, about 68 kDa and about 75 kDa, or about 72 kDa and about 80 kDa
  • the Fc domain is between 55 kDa and 62 kDa (e.g., about 56 kDa, about 57 kDa, about 58 kDa, about 59 kDa, about 60 kDa, or about 61 kDa) in mass.
  • 55 kDa and 62 kDa e.g., about 56 kDa, about 57 kDa, about 58 kDa, about 59 kDa, about 60 kDa, or about 61 kDa
  • viral infection is meant the pathogenic growth of a virus (e.g., RSV such as RSV A or RSV B) in a host organism (e.g., a human subject).
  • a viral infection can be any situation in which the presence of a viral population(s) is damaging to a host body.
  • a subject is “suffering” from a viral infection when an excessive amount of a viral population is present in or on the subject’s body, or when the presence of a viral population(s) is damaging the cells or other tissue of the subject.
  • Fc domain monomer refers to a polypeptide chain that includes at least a hinge domain and second and third antibody constant domains (CH 2 and CH 3 ) or functional fragments thereof (e.g., fragments that that capable of (i) dimerizing with another Fc domain monomer to form an Fc domain, and (ii) binding to an Fc receptor.
  • the Fc domain monomer can be any immunoglobulin antibody isotype, including IgG, IgE, IgM, IgA, or IgD (e.g., IgG).
  • the Fc domain monomer can be an IgG subtype (e.g., IgG1, IgG2a, IgG2b, IgG3, or IgG4) (e.g., IgG1).
  • An Fc domain monomer does not include any portion of an immunoglobulin that is capable of acting as an antigen-recognition region, e.g., a variable domain or a complementarity determining region (CDR).
  • Fc domain monomers in the conjugates as described herein can contain one or more changes from a wild- type Fc domain monomer sequence (e.g., 1-10, 1-8, 1-6, 1-4 amino acid substitutions, additions, or deletions) that alter the interaction between an Fc domain and an Fc receptor.
  • a human Fc domain monomer e.g., an IgG heavy chain, such as IgG1
  • a human Fc domain monomer includes a region that extends from any of Asn201 or Glu216 (e.g., Asn201, Val 202, Asn203, His204, Lys 205, Pro206, Ser207, Asn208, Thr209, Lys210, Val211, Asp212, Lys 213, Lys214, Val215, or Glu216), to the carboxyl-terminus of the heavy chain, e.g., at Gly446 or Lys447.
  • C- terminal Lys447 of the Fc region may or may not be present, without affecting the structure or stability of the Fc region.
  • C-terminal Lys447 of the Fc region may or may not be present, without affecting the structure or stability of the Fc region.
  • C-terminal Lys 447 may be proteolytically cleaved upon expression of the polypeptide.
  • C- terminal Lys 447 is optionally present or absent.
  • the disclosure specifically contemplates any of SEQ ID NOs: 1-4, 11, 16, 19, 20, 32-37, 48-53, and 60-68 that do not include the C-terminal Lys corresponding to Lys447.
  • N-terminal N (Asn) of the Fc region may or may not be present, without affecting the structure of stability of the Fc region.
  • N-terminal Asn may be deamidated upon expression of the polypeptide.
  • N-terminal Asn is optionally present or absent.
  • the disclosure specifically contemplates any of SEQ ID NOs: 60-77 that do not include the N-terminal Asn.
  • numbering of amino acid residues in the IgG or Fc domain monomer is according to the EU numbering system for antibodies, also called the Kabat EU index, as described, for example, in Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD, 1991.
  • the term “Fc domain” refers to a dimer of two Fc domain monomers that is capable of binding an Fc receptor.
  • the two Fc domain monomers dimerize by the interaction between the two CH 3 antibody constant domains, in some embodiments, one or more disulfide bonds form between the hinge domains of the two dimerizing Fc domain monomers.
  • Fab fragment antigen-binding
  • a Fab region is composed of one constant and one variable domain of each of the heavy and light chain. Each heavy chain is comprised of a heavy chain variable region (VH) and a heavy chain constant region (CH).
  • the heavy chain constant region may be comprised of three domains, CH1, CH 2 , and/or CH 3 .
  • Each light chain is comprised of a light chain variable region (VL) and a light chain constant region (CL).
  • VL light chain variable region
  • CL light chain constant region
  • the VH and VL regions can be further subdivided into regions of hypervariability, termed “complementarity determining regions” (CDRs), interspersed with regions that are more conserved, termed “framework regions” (FRs).
  • CDRs complementarity determining regions
  • FRs framework regions
  • the heavy chain e.g., the VH and CH region
  • the heavy chain is linked to the Fc domain monomer by way of a hinge.
  • the Fc domain monomers described herein may include between 10 and/or 20 residues (e.g., 11, 12, 13, 14, 15, 16, 17, 18, or 19 residues) of the Fab domain and hinge region.
  • the N-terminus of the Fc domain monomer is any one of amino acid residues 198-205 (corresponding to a residue of the Fab domain).
  • the N-terminus of the Fc domain monomer is amino acid residue 201 (e.g., Asn 201).
  • the N-terminus of the Fc domain monomer is amino acid residue 202 (e.g., Val 202).
  • Fc-binding peptide refers to refers to a polypeptide having an amino acid sequence of 5 to 50 (e.g., 5 to 40, 5 to 30, 5 to 20, 5 to 15, 5 to 10, 10 to 50, 10 to 30, or 10 to 20) amino acid residues that has affinity for and functions to bind an Fc domain, such as any of the Fc domain described herein.
  • An Fc-binding peptide peptide can be of different origins, e.g., synthetic, human, mouse, or rat.
  • Fc-binding peptides of the invention include Fc-binding peptides which have been engineered to include one or more (e.g., two, three, four, or five) solvent-exposed cysteine or lysine residues, which may provide a site for conjugation to a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker). Most preferably, the Fc-binding peptide will contain a single solvent-exposed cysteine or lysine, thus enabling site-specific conjugation of a compound of the invention. Fc-binding peptides may include only naturally occurring amino acid residues, or may include one or more non-naturally occurring amino acid residues.
  • a non-naturally occurring amino acid residue e.g., the side chain of a non-naturally occurring amino acid residue
  • a compound of the invention e.g., a RSV F protein inhibitor monomer or dimer, including by way of a linker
  • Fc-binding peptides of the invention may be linear or cyclic.
  • Fc-binding peptides of the invention include any Fc-binding peptides known to one of skill in the art.
  • albumin protein refers to a polypeptide including an amino acid sequence corresponding to a naturally-occurring albumin protein (e.g., human serum albumin) or a variant thereof, such as an engineered variant of a naturally-occurring albumin protein.
  • Variants of albumin proteins include polymorphisms, fragments such as domains and sub-domains, and fusion proteins (e.g., an albumin protein having a C-terminal or N-terminal fusion, such as a polypeptide linker).
  • the albumin protein has the amino acid sequence of human serum albumin (HSA) or a variant or fragment thereof, most preferably a functional variant or fragment thereof.
  • Albumin proteins of the invention include proteins having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to any one of SEQ ID NOs: 139-141.
  • Albumin proteins of the invention include albumin proteins which have been engineered to include one or more (e.g., two, three, four, or five) solvent-exposed cysteine or lysine residues, which may provide a site for conjugation to a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker).
  • albumin protein will contain a single solvent-exposed cysteine or lysine, thus enabling site-specific conjugation of a compound of the invention.
  • Albumin proteins may include only naturally occurring amino acid residues, or may include one or more non-naturally occurring amino acid residues. Where included, a non-naturally occurring amino acid residue (e.g., the side chain of a non- naturally occurring amino acid residue) may used as the point of attachment for a compound of the invention (e.g., a RSV F protein inhibitor monomer or dimer, including by way of a linker).
  • albumin protein-binding peptide refers to a polypeptide having an amino acid sequence of 5 to 50 (e.g., 5 to 40, 5 to 30, 5 to 20, 5 to 15, 5 to 10, 10 to 50, 10 to 30, or 10 to 20) amino acid residues that has affinity for and functions to bind an albumin protein, such as any of the albumin proteins described herein.
  • the albumin protein-binding peptide binds to a naturally- occurring serum albumin, most preferably human serum albumin.
  • An albumin protein-binding peptide can be of different origins, e.g., synthetic, human, mouse, or rat.
  • Albumin protein-binding peptides of the invention include albumin protein-binding peptides which have been engineered to include one or more (e.g., two, three, four, or five) solvent-exposed cysteine or lysine residues, which may provide a site for conjugation to a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker).
  • the albumin protein-binding peptide will contain a single solvent-exposed cysteine or lysine, thus enabling site-specific conjugation of a compound of the invention.
  • Albumin protein-binding peptides may include only naturally occurring amino acid residues, or may include one or more non-naturally occurring amino acid residues. Where included, a non-naturally occurring amino acid residue (e.g., the side chain of a non-naturally occurring amino acid residue) may be used as the point of attachment for a compound of the invention (e.g., a RSV F protein inhibitor monomer or dimer, including by way of a linker). Albumin protein-binding peptides of the invention may be linear or cyclic. Albumin protein-binding peptide of the invention include any albumin protein-binding peptides known to one of skill in the art, examples of which, are provided herein.
  • albumin protein-binding peptides are provided in U.S. Patent Application No.2005/0287153, which is incorporated herein by reference in its entirety.
  • a “surface exposed amino acid” or “solvent-exposed amino acid,” such as a surface exposed cysteine or a surface exposed lysine refers to an amino acid that is accessible to the solvent surrounding the protein.
  • a surface exposed amino acid may be a naturally-occurring or an engineered variant (e.g., a substitution or insertion) of the protein.
  • a surface exposed amino acid is an amino acid that when substituted does not substantially change the three- dimensional structure of the protein.
  • linker refers to a covalent linkage or connection between two or more components in a conjugate (e.g., between two RSV F protein inhibitors in a conjugate described herein, between a RSV F protein inhibitor and an Fc domain or albumin protein in a conjugate described herein, and between a dimer of two RSV F protein inhibitors and an Fc domain or an albumin protein in a conjugate described herein).
  • a conjugate described herein may contain a linker that has a trivalent structure (e.g., a trivalent linker).
  • a trivalent linker has three arms, in which each arm is covalently linked to a component of the conjugate (e.g., a first arm conjugated to a first RSV F protein inhibitor, a second arm conjugated to a second RSV F protein inhibitor, and a third arm conjugated to an Fc domain or an albumin protein).
  • a component of the conjugate e.g., a first arm conjugated to a first RSV F protein inhibitor, a second arm conjugated to a second RSV F protein inhibitor, and a third arm conjugated to an Fc domain or an albumin protein.
  • Molecules that may be used as linkers include at least two functional groups, which may be the same or different, e.g., two carboxylic acid groups, two amine groups, two sulfonic acid groups, a carboxylic acid group and a maleimide group, a carboxylic acid group and an alkyne group, a carboxylic acid group and an amine group, a carboxylic acid group and a sulfonic acid group, an amine group and a maleimide group, an amine group and an alkyne group, or an amine group and a sulfonic acid group.
  • two functional groups which may be the same or different, e.g., two carboxylic acid groups, two amine groups, two sulfonic acid groups, a carboxylic acid group and a maleimide group, a carboxylic acid group and an alkyne group, a carboxylic acid group and an amine group, a carboxylic acid group and a sulfonic acid
  • the first functional group may form a covalent linkage with a first component in the conjugate and the second functional group may form a covalent linkage with the second component in the conjugate.
  • two arms of a linker may contain two dicarboxylic acids, in which the first carboxylic acid may form a covalent linkage with the first RSV F protein inhibitor in the conjugate and the second carboxylic acid may form a covalent linkage with the second RSV F protein inhibitor in the conjugate, and the third arm of the linker may for a covalent linkage with an Fc domain or albumin protein in the conjugate. Examples of dicarboxylic acids are described further herein.
  • a molecule containing one or more maleimide groups may be used as a linker, in which the maleimide group may form a carbon-sulfur linkage with a cysteine in a component (e.g., an Fc domain or an albumin protein) in the conjugate.
  • a molecule containing one or more alkyne groups may be used as a linker, in which the alkyne group may form a 1,2,3-triazole linkage with an azide in a component (e.g., an Fc domain or an albumin protein) in the conjugate.
  • a molecule containing one or more azide groups may be used as a linker, in which the azide group may form a 1,2,3-triazole linkage with an alkyne in a component (e.g., an Fc domain or an albumin protein) in the conjugate.
  • a molecule containing one or more bis-sulfone groups may be used as a linker, in which the bis-sulfone group may form a linkage with an amine group a component (e.g., an Fc domain or an albumin protein) in the conjugate.
  • a molecule containing one or more sulfonic acid groups may be used as a linker, in which the sulfonic acid group may form a sulfonamide linkage with a component in the conjugate.
  • a molecule containing one or more isocyanate groups may be used as a linker, in which the isocyanate group may form a urea linkage with a component in the conjugate.
  • a molecule containing one or more haloalkyl groups may be used as a linker, in which the haloalkyl group may form a covalent linkage, e.g., C-N and C-O linkages, with a component in the conjugate.
  • a linker provides space, rigidity, and/or flexibility between the two or more components.
  • a linker may be a bond, e.g., a covalent bond.
  • the term “bond” refers to a chemical bond, e.g., an amide bond, a disulfide bond, a C-O bond, a C-N bond, a N-N bond, a C-S bond, or any kind of bond created from a chemical reaction, e.g., chemical conjugation.
  • a linker includes no more than 250 atoms. In some embodiments, a linker includes no more than 250 non-hydrogen atoms.
  • the backbone of a linker includes no more than 250 atoms.
  • the “backbone” of a linker refers to the atoms in the linker that together form the shortest path from one part of a conjugate to another part of the conjugate (e.g., the shortest path linking a first RSV F protein inhibitor and a second RSV F protein inhibitor).
  • the atoms in the backbone of the linker are directly involved in linking one part of a conjugate to another part of the conjugate (e.g., linking a first RSV F protein inhibitor and a second RSV F protein inhibitor).
  • hydrogen atoms attached to carbons in the backbone of the linker are not considered as directly involved in linking one part of the conjugate to another part of the conjugate.
  • a linker may include a synthetic group derived from, e.g., a synthetic polymer (e.g., a polyethylene glycol (PEG) polymer).
  • a linker may include one or more amino acid residues, such as D- or L-amino acid residues.
  • a linker may be a residue of an amino acid sequence (e.g., a 1-25 amino acid, 1-10 amino acid, 1-9 amino acid, 1-8 amino acid, 1-7 amino acid, 1-6 amino acid, 1-5 amino acid, 1-4 amino acid, 1-3 amino acid, 1-2 amino acid, or 1 amino acid sequence).
  • a linker may include one or more, e.g., 1-100, 1- 50, 1-25, 1-10, 1-5, or 1-3, optionally substituted alkylene, optionally substituted heteroalkylene (e.g., a PEG unit), optionally substituted alkenylene, optionally substituted heteroalkenylene, optionally substituted alkynylene, optionally substituted heteroalkynylene, optionally substituted cycloalkylene, optionally substituted heterocycloalkylene, optionally substituted cycloalkenylene, optionally substituted heterocycloalkenylene, optionally substituted cycloalkynylene, optionally substituted heterocycloalkynylene, optionally substituted arylene, optionally substituted heteroarylene (e.g., pyridine), O, S, NR i (R i is H, optionally substituted alkyl, optionally substituted heteroalkyl, optionally substituted alkenyl, optionally substituted heteroalkenyl, optionally substitute
  • a linker may include one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene (e.g., a PEG unit), optionally substituted C 2 -C 20 alkenylene (e.g., C2 alkenylene), optionally substituted C 2 -C 20 heteroalkenylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene (e.g., cyclopropylene, cyclobutylene), optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycloalkynylene, optionally substitute
  • alkyl straight-chain and branched- chain monovalent substituents, as well as combinations of these, containing only C and H when unsubstituted.
  • alkyl group includes at least one carbon-carbon double bond or carbon-carbon triple bond, the alkyl group can be referred to as an “alkenyl” or “alkynyl” group respectively.
  • alkenyl or alkynyl group respectively.
  • the monovalency of an alkyl, alkenyl, or alkynyl group does not include the optional substituents on the alkyl, alkenyl, or alkynyl group.
  • alkyl, alkenyl, or alkynyl group is attached to a compound
  • monovalency of the alkyl, alkenyl, or alkynyl group refers to its attachment to the compound and does not include any additional substituents that may be present on the alkyl, alkenyl, or alkynyl group.
  • the alkyl or heteroalkyl group may contain, e.g., 1-20.1-18, 1-16, 1-14, 1-12, 1-10, 1-8, 1- 6, 1-4, or 1-2 carbon atoms (e.g., C 1 -C 20 , C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, or C1-C2).
  • the alkenyl, heteroalkenyl, alkynyl, or heteroalkynyl group may contain, e.g., 2-20, 2-18, 2-16, 2-14, 2-12, 2-10, 2-8, 2-6, or 2-4 carbon atoms (e.g., C 2 -C 20 , C 2 -C18, C 2 -C16, C 2 -C14, C 2 -C12, C 2 -C10, C 2 -C8, C 2 -C6, or C 2 -C4).
  • Examples include, but are not limited to, methyl, ethyl, isobutyl, sec-butyl, tert-butyl, 2-propenyl, and 3-butynyl.
  • a heterocycloalkyl, heterocycloalkenyl, or heterocycloalkynyl group refers to a cycloalkyl, cycloalkenyl, or cycloalkynyl group that has one or more heteroatoms independently selected from, e.g., N, O, and S.
  • exemplary heterocycloalkyl groups include pyrrolidine, thiophene, thiolane, tetrahydrofuran, piperidine, and tetrahydropyran.
  • the term “cycloalkyl,” as used herein, represents a monovalent saturated or unsaturated non- aromatic cyclic alkyl group.
  • a cycloalkyl may have, e.g., three to twenty carbons (e.g., a C3-C7, C3-C8, C3-C9, C3-C10, C3-C11, C3-C12, C3-C14, C3-C16, C3-C18, or C3-C20 cycloalkyl).
  • Examples of cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.
  • the cycloalkyl group When the cycloalkyl group includes at least one carbon-carbon double bond, the cycloalkyl group can be referred to as a “cycloalkenyl” group.
  • a cycloalkenyl may have, e.g., four to twenty carbons (e.g., a C4- C7, C4-C8, C4-C9, C4-C10, C4-C11, C4-C12, C4-C14, C4-C16, C4-C18, or C 4 -C 20 cycloalkenyl).
  • Exemplary cycloalkenyl groups include, but are not limited to, cyclopentenyl, cyclohexenyl, and cycloheptenyl.
  • the cycloalkyl group when the cycloalkyl group includes at least one carbon-carbon triple bond, the cycloalkyl group can be referred to as a “cycloalkynyl” group.
  • a cycloalkynyl may have, e.g., eight to twenty carbons (e.g., a C8-C9, C8-C10, C8-C11, C8-C12, C8-C14, C8-C16, C8-C18, or C 8 -C 20 cycloalkynyl).
  • cycloalkyl also includes a cyclic compound having a bridged multicyclic structure in which one or more carbons bridges two non-adjacent members of a monocyclic ring, e.g., bicyclo[2.2.1.]heptyl and adamantane.
  • cycloalkyl also includes bicyclic, tricyclic, and tetracyclic fused ring structures, e.g., decalin and spiro cyclic compounds.
  • aryl refers to any monocyclic or fused ring bicyclic or tricyclic system which has the characteristics of aromaticity in terms of electron distribution throughout the ring system, e.g., phenyl, naphthyl, or phenanthrene.
  • a ring system contains 5-15 ring member atoms or 5-10 ring member atoms.
  • An aryl group may have, e.g., five to fifteen carbons (e.g., a C5-C6, C5-C7, C5-C8, C5-C9, C5-C10, C5-C11, C5-C12, C5-C13, C5-C14, or C 5 -C 15 aryl).
  • heteroaryl also refers to such monocyclic or fused bicyclic ring systems containing one or more, e.g., 1- 4, 1-3, 1, 2, 3, or 4, heteroatoms selected from O, S and N.
  • a heteroaryl group may have, e.g., two to fifteen carbons (e.g., a C 2 -C3, C 2 -C4, C 2 -C5, C 2 -C6, C 2 -C7, C 2 -C8, C 2 -C9. C 2 -C10, C 2 -C11, C 2 -C12, C 2 -C13, C 2 -C14, or C 2 -C 15 heteroaryl).
  • heteroaryl systems include, e.g., pyridyl, pyrimidyl, indolyl, benzimidazolyl, benzotriazolyl, isoquinolyl, quinolyl, benzothiazolyl, benzofuranyl, thienyl, furyl, pyrrolyl, thiazolyl, oxazolyl, isoxazolyl, benzoxazolyl, benzoisoxazolyl, and imidazolyl. Because tautomers are possible, a group such as phthalimido is also considered heteroaryl.
  • the aryl or heteroaryl group is a 5- or 6-membered aromatic rings system optionally containing 1-2 nitrogen atoms.
  • the aryl or heteroaryl group is an optionally substituted phenyl, pyridyl, indolyl, pyrimidyl, pyridazinyl, benzothiazolyl, benzimidazolyl, pyrazolyl, imidazolyl, isoxazolyl, thiazolyl, or imidazopyridinyl.
  • the aryl group is phenyl.
  • an aryl group may be optionally substituted with a substituent such an aryl substituent, e.g., biphenyl.
  • aryl substituent e.g., biphenyl.
  • alkaryl refers to an aryl group that is connected to an alkylene, alkenylene, or alkynylene group. In general, if a compound is attached to an alkaryl group, the alkylene, alkenylene, or alkynylene portion of the alkaryl is attached to the compound.
  • an alkaryl is C6- C35 alkaryl (e.g., C6-C16, C6-C14, C6-C12, C6-C10, C6-C9, C6-C8, C7, or C6 alkaryl), in which the number of carbons indicates the total number of carbons in both the aryl portion and the alkylene, alkenylene, or alkynylene portion of the alkaryl.
  • alkaryls include, but are not limited to, (C1- C8)alkylene(C6-C12)aryl, (C 2 -C8)alkenylene(C6-C12)aryl, or (C 2 -C8)alkynylene(C6-C12)aryl.
  • an alkaryl is benzyl or phenethyl.
  • one or more heteroatoms selected from N, O, and S may be present in the alkylene, alkenylene, or alkynylene portion of the alkaryl group and/or may be present in the aryl portion of the alkaryl group.
  • the substituent may be present on the alkylene, alkenylene, or alkynylene portion of the alkaryl group and/or may be present on the aryl portion of the alkaryl group.
  • amino represents –N(R x )2 or –N + (R x )3, where each R x is, independently, H, alkyl, alkenyl, alkynyl, aryl, alkaryl, cycloalkyl, or two R x combine to form a heterocycloalkyl.
  • the amino group is -NH2.
  • alkamino refers to an amino group, described herein, that is attached to an alkylene (e.g., C1-C5 alkylene), alkenylene (e.g., C 2 -C5 alkenylene), or alkynylene group (e.g., C 2 - C5 alkenylene).
  • alkylene e.g., C1-C5 alkylene
  • alkenylene e.g., C 2 -C5 alkenylene
  • alkynylene group e.g., C 2 - C5 alkenylene
  • the amino portion of an alkamino refers to –N(R x )2 or –N + (R x )3, where each R x is, independently, H, alkyl, alkenyl, alkynyl, aryl, alkaryl, cycloalkyl, or two R x combine to form a heterocycloalkyl.
  • the amino portion of an alkamino is -NH2.
  • An example of an alkamino group is C1-C5 alkamino, e.g., C2 alkamino (e.g., CH 2 CH 2 NH2 or CH 2 CH 2 N(CH 3 )2).
  • heteroalkamino group one or more, e.g., 1-4, 1-3, 1, 2, 3, or 4, heteroatoms selected from N, O, and S may be present in the alkylene, alkenylene, or alkynylene portion of the heteroalkamino group.
  • an alkamino group may be optionally substituted.
  • the substituent may be present on the alkylene, alkenylene, or alkynylene portion of the alkamino group and/or may be present on the amino portion of the alkamino group.
  • alkamide refers to an amide group that is attached to an alkylene (e.g., C1-C5 alkylene), alkenylene (e.g., C 2 -C5 alkenylene), or alkynylene (e.g., C 2 -C5 alkenylene) group.
  • alkylene e.g., C1-C5 alkylene
  • alkenylene e.g., C 2 -C5 alkenylene
  • alkynylene e.g., C 2 -C5 alkenylene
  • the amide portion of an alkamide refers to –C(O)-N(R x )2, where each R x is, independently, H, alkyl, alkenyl, alkynyl, aryl, alkaryl, cycloalkyl, or two R x combine to form a heterocycloalkyl.
  • the amide portion of an alkamide is -C(O)NH2.
  • An alkamide group may be -(CH 2 )2-C(O)NH2 or -CH 2 -C(O)NH2.
  • heteroalkamide group one or more, e.g., 1-4, 1-3, 1, 2, 3, or 4, heteroatoms selected from N, O, and S may be present in the alkylene, alkenylene, or alkynylene portion of the heteroalkamide group.
  • an alkamide group may be optionally substituted.
  • the substituent may be present on the alkylene, alkenylene, or alkynylene portion of the alkamide group and/or may be present on the amide portion of the alkamide group.
  • alkylene alkenylene
  • alkynylene refer to divalent groups having a specified size.
  • an alkylene may contain, e.g., 1-20, 1-18, 1-16, 1-14, 1- 12, 1-10, 1-8, 1-6, 1-4, or 1-2 carbon atoms (e.g., C 1 -C 20 , C1-C18, C1-C16, C1-C14, C1-C12, C1-C10, C1-C8, C1-C6, C1-C4, or C1-C2).
  • an alkenylene or alkynylene may contain, e.g., 2-20, 2-18, 2-16, 2-14, 2-12, 2-10, 2-8, 2-6, or 2-4 carbon atoms (e.g., C 2 -C 20 , C 2 -C18, C 2 -C16, C 2 - C14, C 2 -C12, C 2 -C10, C 2 -C8, C 2 -C6, or C 2 -C4).
  • Alkylene, alkenylene, and/or alkynylene includes straight-chain and branched-chain forms, as well as combinations of these.
  • the divalency of an alkylene, alkenylene, or alkynylene group does not include the optional substituents on the alkylene, alkenylene, or alkynylene group.
  • two RSV F protein inhibitors may be attached to each other by way of a linker that includes alkylene, alkenylene, and/or alkynylene, or combinations thereof.
  • Each of the alkylene, alkenylene, and/or alkynylene groups in the linker is considered divalent with respect to the two attachments on either end of alkylene, alkenylene, and/or alkynylene group.
  • a linker includes -(optionally substituted alkylene)-(optionally substituted alkenylene)-(optionally substituted alkylene)-
  • the alkenylene is considered divalent with respect to its attachments to the two alkylenes at the ends of the linker.
  • the optional substituents on the alkenylene are not included in the divalency of the alkenylene.
  • the divalent nature of an alkylene, alkenylene, or alkynylene group refers to both of the ends of the group and does not include optional substituents that may be present in an alkylene, alkenylene, or alkynylene group.
  • alkylene, alkenylene, and/or alkynylene groups can be substituted by the groups typically suitable as substituents for alkyl, alkenyl and alkynyl groups as set forth herein.
  • -HCR-CoC- may be considered as an optionally substituted alkynylene and is considered a divalent group even though it has an optional substituent, R.
  • Heteroalkylene, heteroalkenylene, and/or heteroalkynylene groups refer to alkylene, alkenylene, and/or alkynylene groups including one or more, e.g., 1-4, 1-3, 1, 2, 3, or 4, heteroatoms, e.g., N, O, and S.
  • a polyethylene glycol (PEG) polymer or a PEG unit -(CH 2 )2-O- in a PEG polymer is considered a heteroalkylene containing one or more oxygen atoms.
  • PEG polyethylene glycol
  • cycloalkylene refers to a divalent cyclic group linking together two parts of a compound.
  • one carbon within the cycloalkylene group may be linked to one part of the compound, while another carbon within the cycloalkylene group may be linked to another part of the compound.
  • a cycloalkylene group may include saturated or unsaturated non-aromatic cyclic groups.
  • a cycloalkylene may have, e.g., three to twenty carbons in the cyclic portion of the cycloalkylene (e.g., a C3-C7, C3-C8, C3-C9, C3-C10, C3-C11, C3-C12, C3-C14, C3-C16, C3-C18, or C3-C20 cycloalkylene).
  • the cycloalkylene group can be referred to as a “cycloalkenylene” group.
  • a cycloalkenylene may have, e.g., four to twenty carbons in the cyclic portion of the cycloalkenylene (e.g., a C4-C7, C4-C8, C4-C9. C4-C10, C4-C11, C4- C12, C4-C14, C4-C16, C4-C18, or C 4 -C 20 cycloalkenylene).
  • the cycloalkylene group can be referred to as a “cycloalkynylene” group.
  • a cycloalkynylene may have, e.g., four to twenty carbons in the cyclic portion of the cycloalkynylene (e.g., a C4-C7, C4-C8, C4-C9. C4-C10, C4-C11, C4-C12, C4-C14, C4-C16, C4-C18, or C 8 -C 20 cycloalkynylene).
  • a cycloalkylene group can be substituted by the groups typically suitable as substituents for alkyl, alkenyl and alkynyl groups as set forth herein.
  • Heterocycloalkylene refers to a cycloalkylene group including one or more, e.g., 1-4, 1-3, 1, 2, 3, or 4, heteroatoms, e.g., N, O, and S.
  • Examples of cycloalkylenes include, but are not limited to, cyclopropylene and cyclobutylene.
  • a tetrahydrofuran may be considered as a heterocycloalkylene.
  • arylene refers to a multivalent (e.g., divalent or trivalent) aryl group linking together multiple (e.g., two or three) parts of a compound. For example, one carbon within the arylene group may be linked to one part of the compound, while another carbon within the arylene group may be linked to another part of the compound.
  • An arylene may have, e.g., five to fifteen carbons in the aryl portion of the arylene (e.g., a C5-C6, C5-C7, C5-C8, C5-C9. C5-C10, C5-C11, C5-C12, C5-C13, C5- C14, or C 5 -C 15 arylene).
  • An arylene group can be substituted by the groups typically suitable as substituents for alkyl, alkenyl and alkynyl groups as set forth herein.
  • Heteroarylene refers to an aromatic group including one or more, e.g., 1-4, 1-3, 1, 2, 3, or 4, heteroatoms, e.g., N, O, and S.
  • a heteroarylene group may have, e.g., two to fifteen carbons (e.g., a C 2 -C3, C 2 -C4, C 2 -C5, C 2 -C6, C 2 -C7, C 2 -C8, C 2 - C9.
  • Substituents include, but are not limited to, alkyl, alkenyl, alkynyl, aryl, alkaryl, acyl, heteroaryl, heteroalkyl, heteroalkenyl, heteroalkynyl, heteroalkaryl, halogen, oxo, cyano, nitro, amino, alkamino, hydroxy, alkoxy, alkanoyl, carbonyl, carbamoyl, guanidinyl, ureido, amidinyl, any of the groups or moieties described above, and hetero versions of any of the groups or moieties described above.
  • Substituents include, but are not limited to, F, Cl, methyl, phenyl, benzyl, OR, NR 2 , SR, SOR, SO2R, OCOR, NRCOR, NRCONR 2 , NRCOOR, OCONR 2 , RCO, COOR, alkyl-OOCR, SO3R, CONR 2 , SO2NR 2 , NRSO2NR 2 , CN, CF3, OCF3, SiR 3 , and NO2, wherein each R is, independently, H, alkyl, alkenyl, aryl, heteroalkyl, heteroalkenyl, or heteroaryl, and wherein two of the optional substituents on the same or adjacent atoms can be joined to form a fused, optionally substituted aromatic or nonaromatic, saturated or unsaturated ring which contains 3–8 members, or two of the optional substituents on the same atom can be joined to form an optionally substituted aromatic or nonaromatic, saturated or unsaturated
  • an optionally substituted group or moiety refers to a group or moiety (e.g., any one of the groups or moieties described above) in which one of the atoms (e.g., a hydrogen atom) is optionally replaced with another substituent.
  • an optionally substituted alkyl may be an optionally substituted methyl, in which a hydrogen atom of the methyl group is replaced by, e.g., OH.
  • a substituent on a heteroalkyl or its divalent counterpart, heteroalkylene may replace a hydrogen on a carbon or a hydrogen on a heteroatom such as N.
  • the hydrogen atom in the group -R-NH-R- may be substituted with an alkamide substituent, e.g., -R-N[(CH 2 C(O)N(CH 3 )2]-R.
  • an optional substituent is a noninterfering substituent.
  • a “noninterfering substituent” refers to a substituent that leaves the ability of the conjugates described herein (e.g., conjugates of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) to either bind to RSV F protein or to inhibit the proliferation of RSV.
  • the substituent may alter the degree of such activity.
  • the substituent will be classified as “noninterfering.” For example, the noninterfering substituent would leave the ability of the compound to provide antiviral efficacy based on an IC50 value of 10 mM or less in a viral plaque reduction assay. Thus, the substituent may alter the degree of inhibition based on plaque reduction or RSV F protein inhibition.
  • hetero when used to describe a chemical group or moiety, refers to having at least one heteroatom that is not a carbon or a hydrogen, e.g., N, O, and S. Any one of the groups or moieties described above may be referred to as hetero if it contains at least one heteroatom.
  • a heterocycloalkyl, heterocycloalkenyl, or heterocycloalkynyl group refers to a cycloalkyl, cycloalkenyl, or cycloalkynyl group that has one or more heteroatoms independently selected from, e.g., N, O, and S.
  • An example of a heterocycloalkenyl group is a maleimido.
  • a heteroaryl group refers to an aromatic group that has one or more heteroatoms independently selected from, e.g., N, O, and S.
  • One or more heteroatoms may also be included in a substituent that replaced a hydrogen atom in a group or moiety as described herein.
  • the substituent may also contain one or more heteroatoms (e.g., methanol).
  • acyl refers to a group having the structure: , wherein R z is an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, alkaryl, alkamino, heteroalkyl, heteroalkenyl, heteroalkynyl, heterocycloalkyl, heterocycloalkenyl, heterocycloalkynyl, heteroaryl, heteroalkaryl, or heteroalkamino.
  • halo or “halogen,” as used herein, refers to any halogen atom, e.g., F, Cl, Br, or I.
  • any one of the groups or moieties described herein may be referred to as a “halo moiety” if it contains at least one halogen atom, such as haloalkyl.
  • hydroxyl as used herein, represents an -OH group.
  • carbonyl as used herein, refers to a group having the structure: .
  • thiocarbonyl refers to a group having the structure:
  • phosphate represents the group having the structure: .
  • phosphoryl represents the group having the structure: or .
  • sulfonyl represents the group having the structure: .
  • amino represents the group having the structure: , wherein R is an optional substituent.
  • N-protecting group represents those groups intended to protect an amino group against undesirable reactions during synthetic procedures. Commonly used N-protecting groups are disclosed in Greene, “Protective Groups in Organic Synthesis,” 5th Edition (John Wiley & Sons, New York, 2014), which is incorporated herein by reference.
  • N-protecting groups include, e.g., acyl, aryloyl, and carbamyl groups such as formyl, acetyl, propionyl, pivaloyl, t-butylacetyl, 2-chloroacetyl, 2-bromoacetyl, trifluoroacetyl, trichloroacetyl, phthalyl, o-nitrophenoxyacetyl, a-chlorobutyryl, benzoyl, carboxybenzyl (CBz), 4-chlorobenzoyl, 4-bromobenzoyl, 4-nitrobenzoyl, and chiral auxiliaries such as protected or unprotected D, L or D, L-amino acid residues such as alanine, leucine, phenylalanine; sulfonyl-containing groups such as benzenesulfonyl and p-toluenesulfonyl; carbamate
  • amino acid means naturally occurring amino acids and non-naturally occurring amino acids.
  • naturally occurring amino acids means amino acids including Ala, Arg, Asn, Asp, Cys, Gln, Glu, Gly, His, Ile, Leu, Lys, Met, Phe, Pro, Ser, Thr, Trp, Tyr, and Val.
  • non-naturally occurring amino acid means an alpha amino acid that is not naturally produced or found in a mammal.
  • non-naturally occurring amino acids include D-amino acids; an amino acid having an acetylaminomethyl group attached to a sulfur atom of a cysteine; a pegylated amino acid; the omega amino acids of the formula NH2(CH 2 )nCOOH where n is 2-6, neutral nonpolar amino acids, such as sarcosine, t-butyl alanine, t-butyl glycine, N-methyl isoleucine, and norleucine; oxymethionine; phenylglycine; citrulline; methionine sulfoxide; cysteic acid; ornithine; diaminobutyric acid; 3-aminoalanine; 3-hydroxy-D-proline; 2,4-diaminobutyric acid; 2-aminopentanoic acid; 2-aminooctanoic acid, 2-carboxy piperazine; piperazine-2-carboxylic acid, 2-amino
  • amino acids are a-aminobutyric acid, a-amino-a- methylbutyrate, aminocyclopropane-carboxylate, aminoisobutyric acid, aminonorbornyl-carboxylate, L- cyclohexylalanine, cyclopentylalanine, L-N-methylleucine, L-N-methylmethionine, L-N-methylnorvaline, L- N-methylphenylalanine, L-N-methylproline, L-N-methylserine, L-N-methyltryptophan, D-ornithine, L-N- methylethylglycine, L-norleucine, a-methyl-aminoisobutyrate, a-methylcyclohexylalanine, D-a- methylalanine, D-a-methylarginine, D-a-methylasparagine, D-a-methylaspartate, D-a-methylcysteine
  • amino acid residues may be charged or polar.
  • Charged amino acids include alanine, lysine, aspartic acid, or glutamic acid, or non-naturally occurring analogs thereof.
  • Polar amino acids include glutamine, asparagine, histidine, serine, threonine, tyrosine, methionine, or tryptophan, or non-naturally occurring analogs thereof. It is specifically contemplated that in some embodiments, a terminal amino group in the amino acid may be an amido group or a carbamate group.
  • percent (%) identity refers to the percentage of amino acid residues of a candidate sequence, e.g., an Fc-IgG, or fragment thereof, that are identical to the amino acid residues of a reference sequence after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent identity (i.e., gaps can be introduced in one or both of the candidate and reference sequences for optimal alignment and non-homologous sequences can be disregarded for comparison purposes). Alignment for purposes of determining percent identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, ALIGN, or Megalign (DNASTAR) software.
  • the percent amino acid sequence identity of a given candidate sequence to, with, or against a given reference sequence is calculated as follows: 100 x (fraction of A/B) where A is the number of amino acid residues scored as identical in the alignment of the candidate sequence and the reference sequence, and where B is the total number of amino acid residues in the reference sequence.
  • the percent amino acid sequence identity of the candidate sequence to the reference sequence would not equal to the percent amino acid sequence identity of the reference sequence to the candidate sequence.
  • Two polynucleotide or polypeptide sequences are said to be “identical” if the sequence of nucleotides or amino acids in the two sequences is the same when aligned for maximum correspondence as described above. Comparisons between two sequences are typically performed by comparing the sequences over a comparison window to identify and compare local regions of sequence similarity.
  • a “comparison window” as used herein refers to a segment of at least about 15 contiguous positions, about 20 contiguous positions, about 25 contiguous positions, or more (e.g., about 30 to about 75 contiguous positions, or about 40 to about 50 contiguous positions), in which a sequence may be compared to a reference sequence of the same number of contiguous positions after the two sequences are optimally aligned.
  • the term “treating” or “to treat,” as used herein, refers to a therapeutic treatment of a viral infection (e.g., a viral infection such as an RSV infection) in a subject. In some embodiments, a therapeutic treatment may slow the progression of the viral infection, improve the subject’s outcome, and/or eliminate the infection.
  • a therapeutic treatment of a viral infection in a subject may alleviate or ameliorate of one or more symptoms or conditions associated with the viral infection, diminish the extent of the viral, stabilize (i.e., not worsening) the state of the viral infection, prevent the spread of the viral infection, and/or delay or slow the progress of the viral infection, as compare the state and/or the condition of the viral infection in the absence of the therapeutic treatment.
  • the average number of monomers of RSV F protein inhibitor or dimers of RSV F protein inhibitors conjugated to an Fc domain monomer may be from 1 to 20 (e.g., the average value of T is 1 to 2, 1 to 3, 1 to 4, 1 to 5, 5 to 10, 10 to 15, or 15 to 20). In some embodiments, the average value of T is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.
  • the term “subject,” as used herein, can be a human or non-human primate.
  • terapéuticaally effective amount refers to an amount, e.g., pharmaceutical dose, effective in inducing a desired effect in a subject or in treating a subject having a condition or disorder described herein (e.g., a viral infection, such as an RSV infection). It is also to be understood herein that a “therapeutically effective amount” may be interpreted as an amount giving a desired therapeutic and/or preventative effect, taken in one or more doses or in any dosage or route, and/or taken alone or in combination with other therapeutic agents (e.g., an antiviral agent described herein).
  • an effective amount of a conjugate is, for example, an amount sufficient to prevent, slow down, or reverse the progression of the viral infection as compared to the response obtained without administration of the conjugate.
  • the term “pharmaceutical composition” refers to a medicinal or pharmaceutical formulation that contains at least one active ingredient (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) as well as one or more excipients and diluents to enable the active ingredient suitable for the method of administration.
  • the pharmaceutical composition of the present disclosure includes pharmaceutically acceptable components that are compatible with a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • a pharmaceutically acceptable carrier refers to an excipient or diluent in a pharmaceutical composition.
  • a pharmaceutically acceptable carrier may be a vehicle capable of suspending or dissolving the active conjugate (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • the pharmaceutically acceptable carrier must be compatible with the other ingredients of the formulation and not deleterious to the recipient.
  • the pharmaceutically acceptable carrier must provide adequate pharmaceutical stability to a conjugate described herein. The nature of the carrier differs with the mode of administration.
  • a solid carrier for oral administration, a solid carrier is preferred; for intravenous administration, an aqueous solution carrier (e.g., WFI, and/or a buffered solution) is generally used.
  • aqueous solution carrier e.g., WFI, and/or a buffered solution
  • pharmaceutically acceptable salt represents salts of the conjugates described herein (e.g., conjugates of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) that are, within the scope of sound medical judgment, suitable for use in methods described herein without undue toxicity, irritation, and/or allergic response.
  • Pharmaceutically acceptable salts are well known in the art. For example, pharmaceutically acceptable salts are described in: Pharmaceutical Salts: Properties, Selection, and Use (Eds.
  • the salts can be prepared in situ during the final isolation and purification of the conjugates described herein or separately by reacting the free base group with a suitable organic acid.
  • the term “about,” as used herein, indicates a deviation of ⁇ 5%. For example, about 10% refers to from 9.5% to 10.5%. Any values provided in a range of values include both the upper and lower bounds, and any values contained within the upper and lower bounds.
  • the term “(1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)”, as used herein, represents the formulas of any one of (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII) (e.g., any one of formulas (1), (2), (D-I), (D-II), (D-II-17), (D- (D-VI-12), (D-VI-13), (D-VI-14), (D-VI-15), (D-VI-16), (D-VI-17), (D-VI-18), (D-VI-19), (D-VI-20), (D-VI-21), (D-VI-22), (D-VI-23), (D-VI-24), (D-VI-25), (D-VI-26), (D-VI-27), (D-VI-28), (D-VI-29), (D-VI-30), (D-VI-31), (D-VI-32), (D-VI-33), (D-
  • FIG.1 is an image depicting exemplary methods of conjugating a RSV F protein inhibitor monomer or dimer, e.g., by way of a linker, to an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide.
  • FIG.2 is an image depicting a method of conjugating a RSV F protein inhibitor monomer or dimer, e.g., by way of a linker, to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide by oxime conjugation to an amino acid residue, e.g., a nitrogen atom of a surface exposed lysine.
  • FIG.3 is an image depicting a method of conjugating a RSV F protein inhibitor monomer or dimer, e.g., by way of a linker, to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide by thioether conjugation to an amino acid residue, e.g., a nitrogen atom of a surface exposed lysine.
  • FIG.4 is an image depicting a method of conjugating a RSV F protein inhibitor monomer or dimer, e.g., by way of a linker, to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide by rebridged cysteine conjugation, e.g., rebridged cysteine conjugation to a pair of sulfur atoms of two hinge cysteines in an Fc domain monomer or Fc domain.
  • FIG.5 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 1.
  • FIG.6 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 3.
  • FIG.7 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 5.
  • FIG.8 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 7.
  • FIG.9 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 9.
  • FIG.10 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 12.
  • FIG.11 shows non-reducing and reducing SDS-PAGE and a schematic illustration of an Fc domain formed from Fc domain monomers having the sequence of SEQ ID NO: 14.
  • FIG.12 is a graph showing the binding of conjugate 6 to the RSV F protein compared to an unconjugated Fc molecule negative control.
  • FIG.13 is a graph showing plasma levels of a conjugate including an Fc domain having a C220S mutation (SEQ ID NO: 73) (2 mpk IV) compared to a conjugate including an Fc domain having a C220S mutation and a YTE triple mutation (SEQ ID NO: 76) (2 mpk IV) in non-human primate PK studies determined by Fc capture. This study was performed as described in Example 38.
  • FIG.14 is a graph showing plasma concentration levels of of a conjugate including an Fc domain having a C220S mutation (SEQ ID NO: 73) compared to epithelial lining fluid (ELF) levels of the conjugate in mice. This study was performed as described in Example 40.
  • FIG.15 is an image depicting exemplary conjugates of an RSV F protein inhibitor monomer or dimer and an Fc domain monomer or an Fc domain.
  • T is representative of the drug-to-antibody ratio (DAR) and depicts that multiple monomers or dimers can be conjugated to each Fc domain monomer or Fc domain.
  • FIG.16 is an image depicting exemplary conjugates of an RSV F protein inhibitor monomer or dimer (e.g, an RSV F protein inhibitor having a structure described by Formula (A-III)) and an Fc domain monomer or an Fc domain.
  • “T” is representative of the drug-to-antibody ratio (DAR) and depicts that multiple monomers or dimers can be conjugated to each Fc domain monomer or Fc domain.
  • FIG.17 is an image depicting exemplary conjugates of an RSV F protein inhibitor monomer or dimer (e.g, an RSV F protein inhibitor having a structure described by Formula (A-IV)) and an Fc domain monomer or an Fc domain.
  • RSV F protein inhibitor monomer or dimer e.g, an RSV F protein inhibitor having a structure described by Formula (A-IV)
  • T is representative of the drug-to-antibody ratio (DAR) and depicts that multiple monomers or dimers can be conjugated to each Fc domain monomer or Fc domain.
  • DAR drug-to-antibody ratio
  • the disclosure features conjugates, compositions, and methods for the treatment of viral infections (e.g., RSV such as RSV A or RSV B).
  • the conjugates disclosed herein include monomers or dimers of viral RSV F protein inhibitors (e.g., Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof) conjugated to Fc monomers, Fc domains, Fc-binding peptides, albumin proteins, or albumin protein-binding peptides.
  • RSV F protein inhibitor e.g., Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof
  • the Fc monomers or Fc domains in the conjugates bind to FcgRs (e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb) on immune cells, e.g., neutrophils, to activate phagocytosis and effector functions, such as antibody-dependent cell-mediated cytotoxicity (ADCC), thus leading to the engulfment and destruction of viral particles by immune cells and further enhancing the antiviral activity of the conjugates.
  • FcgRs e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb
  • immune cells e.g., neutrophils
  • ADCC antibody-dependent cell-mediated cytotoxicity
  • the albumin or albumin-binding peptide may extend the half-life of the conjugate, for example, by binding of albumin to the recycling neon
  • compositions are useful in methods for the inhibition of viral growth and in methods for the treatment of viral infections, such as those caused by an RSV A and RSV B.
  • the featured conjugates exhibit desirable tissue distribution (e.g., lung distribution).
  • Such compositions are therefore useful in methods for the treatment of disorders (e.g., respiratory disorders, inhibition of infection growth, and in methods for the treatment of infections (e.g., viral infections (e.g., RSV such as RSV A or RSV B).
  • infections e.g., viral infections (e.g., RSV such as RSV A or RSV B).
  • Viral Infections The compounds and pharmaceutical compositions described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) can be used to treat a viral infection (e.g., an RSV A or RSV B viral infection).
  • a viral infection e.g., an RSV A or RSV B viral infection.
  • Viral infection refers to the pathogenic growth of a virus (e.g., RSV such as RSV A or RSV B) in a host organism (e.g., a human subject).
  • a viral infection can be any situation in which the presence of a viral population(s) is damaging to a host body.
  • a subject is suffering from a viral infection when an excessive amount of a viral population is present in or on the subject’s body, or when the presence of a viral population(s) is damaging the cells or other tissue of the subject.
  • Human respiratory syncytial virus (RSV) is a medium-sized (120–200 nm) enveloped virus that contains a lipoprotein coat and a linear negative-sense RNA genome (must be converted to a positive RNA prior to translation).
  • the former contains virally encoded F, G, and SH lipoproteins.
  • the F and G lipoproteins are the only two that target the cell membrane, and are highly conserved among RSV isolates.
  • HRSV Human RSV
  • a and B Human RSV
  • Subtype B is characterized as the asymptomatic strains of the virus that the majority of the population experiences. The more severe clinical illnesses involve subtype A strains, which tend to predominate in most outbreaks.
  • Four of the viral genes code for intracellular proteins that are involved in genome transcription, replication, and particle budding, namely N (nucleoprotein), P (phosphoprotein), M (matrix protein), and L (“large” protein, containing the RNA polymerase catalytic motifs).
  • the RSV genomic RNA forms a helical ribonucleoprotein (RNP) complex with the N protein, termed nucleocapsid, which is used as template for RNA synthesis by the viral polymerase complex.
  • RNP helical ribonucleoprotein
  • N RSV nucleoprotein
  • the three-dimensional crystal structure of a decameric, annular ribonucleoprotein complex of the RSV nucleoprotein (N) bound to RNA has been determined at 3.3 ⁇ resolution. This complex mimics one turn of the viral helical nucleocapsid complex. Its crystal structure was combined with electron microscopy data to provide a detailed model for the RSV nucleocapsid.
  • Conjugates of the Disclosure Provided herein are synthetic conjugates useful in the treatment of viral infections (e.g., RSV infections).
  • the conjugates disclosed herein include an Fc domain or an albumin protein conjugated to one or more monomers RSV F protein inhibitors or one or more dimers of two RSV F protein inhibitors (e.g., RSV F protein inhibitors selected from Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof).
  • RSV F protein inhibitors selected from Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, or an analog thereof.
  • the dimers of two RSV F protein inhibitors include a RSV F protein inhibitor (e.g., a first RSV F protein inhibitor of formula (A-I), (A-II), (A-III), (A-IV), (A-V), or (A-VI)) and a second RSV F protein inhibitor (e.g., a second RSV F protein inhibitor of formula (A-I), (A-II), (A-III), (A-IV), (A-V), or (A-VI)).
  • a RSV F protein inhibitor e.g., a first RSV F protein inhibitor of formula (A-I), (A-II), (A-III), (A-IV), (A-V), or (A-VI)
  • a second RSV F protein inhibitor e.g., a second RSV F protein inhibitor of formula (A-I), (A-II), (A-III), (A-IV), (A-V), or (A-VI)
  • the dimers of two RSV F protein inhibitors include a RSV F protein inhibitiber (e.g., a first RSV F protein inhibitor of formula (A-IIIa), (A-III-b), (A-IIIc), (A-IIId), (A-III-e), or (A-IIIf)) and a second RSV F protein inhibitor (e.g., a second RSV F protein inhibitior of formula (A-IIIa), (A-III-b), (A-IIIc), (A- IIId), (A-III-e), or (A-IIIf)).
  • a RSV F protein inhibitiber e.g., a first RSV F protein inhibitor of formula (A-IIIa), (A-III-b), (A-IIIc), (A-IIId), (A-III-e), or (A-IIIf)
  • a second RSV F protein inhibitor e.g., a second RSV F protein inhibitior of formula (A-IIIa), (A-III-b), (A-
  • the dimers of two RSV F protein inhibitors include a RSV F protein inhibitiber (e.g., a first RSV F protein inhibitor of formula (A-IVa), (A-IVb), (A-IVc), (A-IVd), (A-IVe), or (A-IVf)) and a second RSV F protein inhibitor (e.g., a second RSV F protein inhibitior of formula (A-IVa), (A-IVb), (A-IVc), (A-IVd), (A-IVe), or (A-IVf)).
  • a RSV F protein inhibitiber e.g., a first RSV F protein inhibitor of formula (A-IVa), (A-IVb), (A-IVc), (A-IVd), (A-IVe), or (A-IVf)
  • a second RSV F protein inhibitor e.g., a second RSV F protein inhibitior of formula (A-IVa), (A-IVb), (A-IVc), (A-IV
  • the dimers of two RSV F protein inhibitors include a RSV F protein inhibitiber (e.g., a first RSV F protein inhibitor of formula (A-IIIb), (A-IIIc), (A-IV), (A-V), or (A-VI)) and a second RSV F protein inhibitor (e.g., a second RSV F protein inhibitior of formula (A-IIIb), (A-IIIc), (A-IV), (A-V), or (A-VI)).
  • the first and second RSV F protein inhibitors are linked to each other by way of a linker.
  • conjugates described herein bind to the surface of a viral particle (e.g., bind to viral RSV F protein on the surface an RSV particle) through the interactions between the RSV F protein inhibitor moieties in the conjugates and proteins on the surface of the viral particle.
  • the RSV F protein inhibitor disrupts RSV F protein-mediated fusion with the host cell membrane, preventing viral entry. The process of membrane fusion begins once prefusion RSV F protein is triggered by an unknown mechanism to initiate a dramatic conformational change, refolding and bringing the RSV and host cell membrane together.
  • Conjugates of the invention include RSV F protein inhibitor monomers and dimers conjugated to an Fc domain, Fc monomer, or Fc-binding peptide.
  • the Fc domain in the conjugates described herein binds to the FcgRs (e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb) on immune cells.
  • the binding of the Fc domain in the conjugates described herein to the FcgRs on immune cells activates phagocytosis and effector functions, such as antibody-dependent cell-mediated cytotoxicity (ADCC), thus leading to the engulfment and destruction of viral particles by immune cells and further enhancing the antiviral activity of the conjugates.
  • Conjugates of the invention include RSV F protein inhibitor monomers and dimers conjugated to an albumin protein or an albumin protein-binding peptide.
  • the albumin protein or albumin protein-binding peptide may extend the half-life of the conjugate, for example, by binding of albumin to the recycling neonatal Fc receptor.
  • Conjugates provided herein are described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)- (M-VII).
  • the conjugates described herein include one or more monomers of RSV F protein inhibitors conjugated to an Fc domain or an albumin protein.
  • the conjugates described herein include one or more dimers of RSV F protein inhibitors conjugated to an Fc domain or an albumin protein.
  • E an Fc domain monomer dimerizes to form an Fc domain.
  • Conjugates described herein may be synthesized using available chemical synthesis techniques in the art. In cases where a functional group is not available for conjugation, a molecule may be derivatized using conventional chemical synthesis techniques that are well known in the art.
  • the conjugates described herein contain one or more chiral centers. The conjugates include each of the isolated stereoisomeric forms as well as mixtures of stereoisomers in varying degrees of chiral purity, including racemic mixtures. It also encompasses the various diastereomers, enantiomers, and tautomers that can be formed.
  • RSV F protein inhibitors A component of the conjugates described herein is an RSV F protein inhibitor moiety.
  • the RSV F protein inhibitor disrupts RSV F protein, an envelope glycoprotein that causes the virion membrane to fuse with a target cell membrane.
  • the functional F protein trimer in the virion membrane is in a metastable, prefusion form. It is not yet clear what causes the F protein to trigger, but the result is a major refolding into its postfusion form.
  • FP fusion peptide
  • the FP is mirrored by the transmembrane (TM) domain near the C-terminus of F1, and each is connected to a heptad repeat (HR) in this order: FP-HRA-HRB-TM.
  • RSV F protein inhibitors include Presatovir, MDT 637, JNJ 179, TMC353121, or Ziresovir.
  • derivatives of Presatovir, MDT 637, JNJ 179, TMC353121, and Ziresovir have RSV F protein inhibitor activity and are useful as RSV F protein inhibitor moieties of the compounds herein (see, for example, Cockerill et al. J. Med. Chem.62(7): 3206-3227, 2018).
  • Conjugates described herein are separated into two types: (1) one or more dimers of RSV F protein inhibitors conjugated to an Fc domain or an albumin protein and (2) one or more monomers of RSV F protein inhibitors conjugated to an Fc domain or an albumin protein.
  • RSV F protein inhibitors are linked to each other by way of a linker, such as the linkers described herein.
  • Viral RSV F protein inhibitors of the invention include Presatovir, MDT 637, JNJ 179, TMC353121, Ziresovir, and analogs thereof, such as the viral RSV F protein inhibitors of formulas (A-I)- (A-VI).
  • the RSV F protein inhibitor is selected from Presatovir (described, for example, as Compound 202 in U.S. Patent No.8,486,938), MDT 637 (described, for example, in Example 13 of U.S.
  • Patent No.6,495,580 JNJ 179 (described, for example, as Compound 179 of International Patent Publication No. WO 2014/060411), TMC353121 or an analog thereof (e.g., Analog 1, 2, or 3 of below), or Ziresovir: , .
  • Ziresovir Conjugates of dimers of RSV F proteininhibitors linked to an Fc domain or an albumin protein The conjugates described herein include an Fc domain, and Fc monomer, an Fc-binding peptide, and albumin protein, or an albumin protein-binding peptide covalently linked to one or more dimers of RSV F protein inhibitors.
  • the dimers of two RSV F protein inhibitors include a first RSV F protein inhibitor (e.g., a first viral RSV F protein inhibitor of formulas (A-I)-(A-VI)) and a second RSV F protein inhibitor (e.g., a second viral RSV F protein inhibitor of formulas (A-I)-(A-VI)).
  • the first and second RSV F protein inhibitors are linked to each other by way of a linker, such as a linker described herein.
  • the first and second RSV F protein inhibitors are the same.
  • the first and second RSV F protein inhibitors are different.
  • each A 1 -L-A 2 may be independently selected (e.g., independently selected from any of the A 1 -L-A 2 structures described herein).
  • E may be conjugated to 2, 3, 4, 5, 6, 7, 8, 9, 10, or more different A 1 -L-A 2 moieties.
  • E is conjugated to a first A 1 -L-A 2 moiety, and a second A 1 -L-A 2 , moiety.
  • each of A 1 and A 2 of the first A 1 -L-A 2 moiety and of the second A 1 -L-A 2 moiety are independently selected from any one of formulas (A- I)-(A-VI).
  • the first A 1 -L-A 2 moiety is conjugated specifically to lysine residues of E (e.g., the nitrogen atoms of surface exposed lysine residues of E), and the second A 1 -L-A 2 moiety is conjugated specifically to cysteine residues of E (e.g., the sulfur atoms of surface exposed cysteine residues of E).
  • the first A 1 -L-A 2 moiety is conjugated specifically to cysteine residues of E (e.g., the sulfur atoms of surface exposed cysteine residues of E), and the second A 1 -L-A 2 moiety is conjugated specifically to lysine residues of E (e.g., the nitrogen atoms of surface exposed lysine residues of E).
  • the squiggly line connected to E indicates that one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) dimers of RSV F protein inhibitors may be attached to an Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) dimers of RSV F protein inhibitors may be attached to an Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • one or more dimers of RSV F protein inhibitors may be attached to an Fc domain.
  • the squiggly line in the conjugates described herein is not to be construed as a single bond between one or more dimers of RSV F protein inhibitors and an atom in the Fc domain or albumin protein.
  • T when T is 1, one dimer of RSV F protein inhibitors may be attached to an atom in the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • two dimers of RSV F protein inhibitors may be attached to an atom in the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • a linker in a conjugate described herein e.g., L or L’
  • a linker in a conjugate described herein e.g., L or L’
  • the linker when the linker has three arms, two of the arms may be attached to the first and second RSV F protein inhibitors and the third arm may be attached to the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • the linker when n is 2, two Fc domain monomers (each Fc domain monomer is represented by E) dimerize to form an Fc domain.
  • Conjugates of monomers of RSV F protein inhibitors linked to an Fc domain or an albumin protein include an Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide covalently linked to one or more monomers of RSV F protein inhibitors.
  • Conjugates of an Fc domain monomer or albumin protein and one or more monomers of RSV F protein inhibitors may be formed by linking the Fc domain or albumin protein to each of the monomers of RSV F protein inhibitors through a linker, such as any of the linkers described herein.
  • the squiggly line connected to E indicates that one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) monomers of RSV F protein inhibitors may be attached to an Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • n is 1, one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) monomers of RSV F protein inhibitors may be attached to an Fc domain monomer or an albumin protein.
  • one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) monomers of RSV F protein inhibitors may be attached to an Fc domain.
  • the squiggly line in the conjugates described herein is not to be construed as a single bond between one or more monomers of RSV F protein inhibitors and an atom in the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • T when T is 1, one monomer of RSV F protein inhibitor may be attached to an atom in the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide. In some embodiments, when T is 2, two monomers of RSV F protein inhibitors may be attached to an atom in the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • each A 1 -L may be independently selected (e.g., independently selected from any of the A 1 -L structures described herein).
  • E may be conjugated to 2, 3, 4, 5, 6, 7, 8, 9, 10, or more different A 1 -L moieties.
  • E is conjugated to a first A 1 -L moiety, and a second A 1 -L, moiety.
  • a 1 of each of the first A 1 -L moiety and the second A 1 - L moiety is independently selected from any one of formulas (A-I)-(A-VI).
  • the first A 1 -L moiety is conjugated specifically to lysine residues of E (e.g., the nitrogen atoms of surface exposed lysine residues of E), and the second A 1 -L moiety is conjugated specifically to cysteine residues of E (e.g., the sulfur atoms of surface exposed cysteine residues of E).
  • the first A 1 -L moiety is conjugated specifically to cysteine residues of E (e.g., the sulfur atoms of surface exposed cysteine residues of E)
  • the second A 1 -L moiety is conjugated specifically to lysine residues of E (e.g., the nitrogen atoms of surface exposed lysine residues of E).
  • a linker in a conjugate having an Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide covalently linked to one or more monomers of the RSV F protein inhibitors described herein may be a divalent structure having two arms. One arm in a divalent linker may be attached to the monomer of the RSV F protein inhibitor and the other arm may be attached to the Fc domain monomer, Fc domain, Fc-binding peptide, albumin protein, or albumin protein-binding peptide.
  • Fc domain monomers and Fc domains An Fc domain monomer includes a hinge domain, a CH 2 antibody constant domain, and a CH 3 antibody constant domain.
  • the Fc domain monomer can be of immunoglobulin antibody isotype IgG, IgE, IgM, IgA, or IgD.
  • the Fc domain monomer can also be of any immunoglobulin antibody isotype (e.g., IgG1, IgG2a, IgG2b, IgG3, or IgG4).
  • the Fc domain monomer can be of any immunoglobulin antibody allotype (e.g., IGHG1*01 (i.e., G1m(za)), IGHG1*07 (i.e., G1m(zax)), IGHG1*04 (i.e., G1m(zav)), IGHG1*03 (G1m(f)), IGHG1*08 (i.e., G1m(fa)), IGHG2*01, IGHG2*06, IGHG2*02, IGHG3*01, IGHG3*05, IGHG3*10, IGHG3*04, IGHG3*09, IGHG3*11, IGHG3*12, IGHG3*06, IGHG3*07,
  • the Fc domain monomer can also be of any species, e.g., human, murine, or mouse.
  • a dimer of Fc domain monomers is an Fc domain that can bind to an Fc receptor, which is a receptor located on the surface of leukocytes.
  • an Fc domain monomer in the conjugates described herein may contain one or more amino acid substitutions, additions, and/or deletion relative to an Fc domain monomer having a sequence of any one of SEQ ID NOs: 1-138.
  • an Asn in an Fc domain monomer in the conjugates as described herein may be replaced by Ala in order to prevent N-linked glycosylation (see, e.g., SEQ ID NOs: 12-15, where Asn to Ala substitution is labeled with *).
  • an Fc domain monomer in the conjugates described herein may also containing additional Cys additions (see, e.g., SEQ ID NOs: 9, 10, and 11, where Cys additions are labeled with *).
  • an Fc domain monomer in the conjugates as described herein includes an additional moiety, e.g., an albumin-binding peptide, a purification peptide (e.g., a hexa-histidine peptide (HHHHHH (SEQ ID NO: 99)), or a signal sequence (e.g., IL2 signal sequence MYRMQLLSCIALSLALVTNS (SEQ ID NO: 100)) attached to the N- or C-terminus of the Fc domain monomer.
  • an additional moiety e.g., an albumin-binding peptide, a purification peptide (e.g., a hexa-histidine peptide (HHHHHH (SEQ ID NO: 99)), or a signal sequence (e.g., IL2 signal sequence MYRMQLLSCIALSLALVTNS (SEQ ID NO: 100)) attached to the N- or C-terminus of the Fc domain monomer.
  • an Fc domain monomer in the conjugate does not contain any type of antibody variable region, e.g., VH, VL, a complementarity determining region (CDR), or a hypervariable region (HVR).
  • an Fc domain monomer in the conjugates as described herein may have a sequence that is at least 95% identical (e.g., 97%, 99%, or 99.5% identical) to the sequence of any one of SEQ ID NOs: 1-138 shown below.
  • an Fc domain monomer in the conjugates as described herein may have a sequence of any one of SEQ ID NOs: 1-138 shown below.
  • SEQ ID NO: 1 murine Fc-IgG2a with IL2 signal sequence at the N-terminus (bold) MYRMQLLSCIALSLALVTNSPRGPTIKPCPPCKCPAPNLLGGPSVFIFPPKIKDVLMISLSPIVTCVVVDVS EDDPDVQISWFVNNVEVHTAQTQTHREDYNSTLRVVSALPIQHQDWMSGKEFKCKVNNKDLPAPIERTI SKPKGSVRAPQVYVLPPPEEEMTKKQVTLTCMVTDFMPEDIYVEWTNNGKTELNYKNTEPVLDSDGSYF MYSKLRVEKKNWVERNSYSCSVVHEGLHNHHTTKSFSRTPGK SEQ ID NO: 2: mature murine Fc-IgG2a PRGPTIKPCPPCKCPAPNLLGGPSVFIFPPKIKDVLMISLSPIVTCVVVDVSEDDPDVQISWFVNNVEVHTA QTQTHREDYNSTLRVVSA
  • An Fc domain forms the minimum structure that binds to an Fc receptor, e.g., Fc-gamma receptors (i.e., Fcg receptors (FcgR)), Fc-alpha receptors (i.e., Fca receptors (FcaR)), Fc-epsilon receptors (i.e., Fce receptors (FceR)), and/or the neonatal Fc receptor (FcRn).
  • Fc-gamma receptors i.e., Fcg receptors (FcgR)
  • Fc-alpha receptors i.e., Fca receptors (FcaR)
  • Fc-epsilon receptors i.e., Fce receptors (FceR)
  • FcRn neonatal Fc receptor
  • an Fc domain of the present invention binds to an Fcg receptor (e.g., FcRn, FcgRI (CD64), FcgRIIa (CD32), FcgRIIb (CD32), FcgRIIIa (CD16a), FcgRIIIb (CD16b)), and/or FcgRIV and/or the neonatal Fc receptor (FcRn).
  • Fcg receptor e.g., FcRn, FcgRI (CD64), FcgRIIa (CD32), FcgRIIb (CD32), FcgRIIIa (CD16a), FcgRIIIb (CD16b)
  • the Fc domain monomer or Fc domain of the invention is an aglycosylated Fc domain monomer or Fc domain (e.g., an Fc domain monomer or and Fc domain that maintains engagement to an Fc receptor (e.
  • the Fc domain is an aglycosylated IgG1 variants that maintains engagement to an Fc receptor (e.g., an IgG1 having an amino acid substitution at N297 and/or T299 of the glycosylation motif).
  • an Fc receptor e.g., an IgG1 having an amino acid substitution at N297 and/or T299 of the glycosylation motif.
  • Exemplary aglycosylated Fc domains and methods for making aglycosylated Fc domains are known in the art, for example, as described in Sazinsky S.L. et al., Aglycosylated immunoglobulin G1 variants productively engage activating Fc receptors, PNAS, 2008, 105(51):20167-20172, which is incorporated herein in its entirety.
  • the Fc domain or Fc domain monomer of the invention is engineered to enhance binding to the neonatal Fc receptor (FcRn).
  • the Fc domain may include the triple mutation corresponding to M252Y/S254T/T256E (YTE) (e.g., an IgG1, such as a human or humanized IgG1 having a YTE mutation, for example SEQ ID NO: 33, SEQ ID NO: 36, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 56, or SEQ ID NO: 57).
  • YTE M252Y/S254T/T256E
  • the Fc domain may include the double mutant corresponding to M428L/N434S (LS) (e.g., an IgG1, such as a human or humanized IgG1 having an LS mutation, such as SEQ ID NO: 37, SEQ ID NO: 39, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 54, SEQ ID NO: 55, or SEQ ID NO: 59).
  • the Fc domain may include the single mutant corresponding to N434H (e.g., an IgG1, such as a human or humanized IgG1 having an N434H mutation).
  • the Fc domain may include the single mutant corresponding to C220S (e.g., and IgG1, such as a human or humanized IgG1 having a C220S mutation, such as SEQ ID NO: 34, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 58, SEQ ID NO: 59, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, or SEQ ID NO: 68).
  • C220S e.g., and IgG1, such as a human or humanized IgG1 having a C220S mutation, such as SEQ ID NO: 34, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, S
  • the Fc domain may include a quadruple mutant corresponding to C220S/L309D/Q311H/N434S (CDHS) (e.g., an IgG1, such as a human or humanized IgG1 having a CDHS mutation, such as SEQ ID NO: 96, SEQ ID NO: 97, SEQ ID NO: 98, SEQ ID NO: 99, SEQ ID NO: 100, SEQ ID NO: 101, SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105, SEQ ID NO: 106, SEQ ID NO: 107, SEQ ID NO: 108, SEQ ID NO: 109, SEQ ID NO: 110, SEQ ID NO: 111, SEQ ID NO: 112, SEQ ID NO: 113, SEQ ID NO: 114, SEQ ID NO: 115, SEQ ID NO: 116, and SEQ ID NO: 117).
  • CDHS C220S/L30
  • the Fc domain may include a triple mutant corresponding to L309D/Q211H/N434S (DHS) (e.g., an IgG1, such as a human or humanized IgG1 having a DHS mutation, such as SEQ ID NO: 118, SEQ ID NO: 119, SEQ ID NO: 120, SEQ ID NO: 121, SEQ ID NO: 122, SEQ ID NO: 123, SEQ ID NO: 124, SEQ ID NO: 125, SEQ ID NO: 126, SEQ ID NO: 127, SEQ ID NO: 128, SEQ ID NO: 129, SEQ ID NO: 130, SEQ ID NO: 131, SEQ ID NO: 132, SEQ ID NO: 133, SEQ ID NO: 134, SEQ ID NO: 135, SEQ ID NO: 136, SEQ ID NO: 137, and SEQ ID NO: 138).
  • DHS L309D/Q211H/N434S
  • the Fc domain may include a combination of one or more of the above-described mutations that enhance binding to the FcRn.
  • Enhanced binding to the FcRn may increase the half-life Fc domain-containing conjugate.
  • incorporation of one or more amino acid mutations that increase bidning to the FcRn e.g., a YTE mutation, an LS mutation, or an N434H mutantion
  • Exemplary Fc domains with enhanced binding to the FcRN and methods for making Fc domains having enhanced binding to the FcRN are known in the art, for example, as described in Maeda, A. et al., Identification of human IgG1 variant with enhanced FcRn binding and without increased binding to rheumatoid factor autoantibody, MABS, 2017, 9(5):844-853, which is incorporated herein in its entirety.
  • an amino acid “corresponding to” a particular amino acid residue e.g., of a particular SEQ ID NO.
  • any one of SEQ ID NOs: 1-138 may be mutated to include a YTE mutation, an LS mutation, and/or an N434H mutation by mutating the “corresponding residues” of the amino acid sequence.
  • the Fc-domain containing composition includes an Fc domain monomer.
  • the Fc domain monomer is a variant Fc domain (e.g., a variant of a parent Fc polypeptide).
  • the Fc domain monomer may include an amino acid substitution at position 220.
  • the Fc domain monomer may include amino acid substitutions at position 220 and positions 252, 254, and 256.
  • the Fc domain monomer may include amino acid substitutions at positions 309, 311, and 434.
  • the substitution at position 220 is a serine
  • the substitution at position 252 is a tyrosine
  • the substitution at position at position 254 is a threonine
  • the substitution at position 256 is a glutamic acid
  • the substitution at position 309 is an aspartic acid
  • the substitution at position at position 311 is a histidine
  • the substitution at position 434 is a serine.
  • the Fc domain monomer includes substitutions at positions 220, 252, 254, and 256, where numbering is according to the EU index as in Kabat, and where the substitution at position 220 is a serine, the substitution at position 252 is a tyrosine, the substitution at position at position 254 is a threonine, and the substitution at position 256 is a glutamic acid.
  • the substitution at position 220 is a cysteine to serine (C220S).
  • the substitution at position 252 is a methionine to tyrosine (M252Y).
  • the substitution at position 254 is a serine to threonine (S254T).
  • the substitution at position 252 is a threonine to glutamate (T256E).
  • the substitution at position 309 is a valine to aspartic acid (V309D).
  • the substitution at position 311 is a glutamine to histidine (Q311H).
  • the substitution at position 434 is an asparagine to serine (N434S).
  • the amino acid numbering of a variant Fc monomer as indicated above and throughout the disclosure is according to the EU index as in Kabat. Amino acid substitutions are relative to a wild-type Fc monomer amino acid sequence, e.g., wild-type human IgG1 or IgG2.
  • the Fc domain monomer includes less than about 300 amino acid residues (e.g., less than about 300, less than about 295, less than about 290, less than about 285, less than about 280, less than about 275, less than about 270, less than about 265, less than about 260, less than about 255, less than about 250, less than about 245, less than about 240, less than about 235, less than about 230, less than about 225, or less than about 220 amino acid residues).
  • the Fc domain monomer is less than about 40 kDa (e.g., less than about 35 kDa, less than about 30 kDa, less than about 25 kDa).
  • the Fc domain monomer includes at least 200 amino acid residues (e.g., at least 210, at least 220, at least 230, at least 240, at least 250, at least 260, at least 270, at least 280, at least 290, or at least 300 amino residues). In some embodiments, the Fc domain monomer is at least 20 kDa (e.g., at least 25 kDa, at least 30 kDa, or at least 35 kDa). In some embodiments, the Fc domain monomer includes 200 to 400 amino acid residues (e.g., 200 to 250, 250 to 300, 300 to 350, 350 to 400, 200 to 300, 250 to 350, or 300 to 400 amino acid residues).
  • the Fc domain monomer is between 200 and 300 amino acid residues (e.g., between 210 and 300, between 230 and 300, between 250 and 300, between 270 and 300, between 290 and 300, between 210 and 290, between 220 and 280, between 230 and 270, between 240 and 260, or between 245 and 255 amino acid residues) in length.
  • amino acid residues e.g., between 210 and 300, between 230 and 300, between 250 and 300, between 270 and 300, between 290 and 300, between 210 and 290, between 220 and 280, between 230 and 270, between 240 and 260, or between 245 and 255 amino acid residues
  • the Fc domain monomer is between 240 and 255 amino acid residues (e.g., 241 amino acid residues, 242 amino acid residues, 243 amino acid residues, 244 amino acid residues, 245 amino acid residues, 246 amino acid residues, 247 amino acid residues, 248 amino acid residues, 249 amino acid residues, 250 amino acid residues, 251 amino acid residues, 252 amino acid residues, 253 amino acid residues, or 254 amino acid residues). In even more particular embodiments, the Fc domain monomer is 246 amino acid residues in length.
  • the Fc domain monomer is 20 to 40 kDa (e.g., 20 to 25 kDa, 25 to 30 kDa, 35 to 40 kDa, 20 to 30 kDa, 25 to 35 kDa, or 30 to 40 KDa). In some embodiments, the Fc domain monomer is between about 20 kDa and about 40 kDa (e.g., 20 kDa to 25 kDa, 25k Da to 30k Da, 30k Da to 35k Da, 35k Da to 40 kDa) in mass.
  • the Fc domain monomer includes a serine at amino acid position 220, wherein the amino acid numbering is according to the EU index as in Kabat, and wherein the Fc domain monomer is between 200 and 300 amino acid residues (e.g., between 210 and 300, between 230 and 300, between 250 and 300, between 270 and 300, between 290 and 300, between 210 and 290, between 220 and 280, between 230 and 270, between 240 and 260, or between 245 and 255 amino acid residues) in length.
  • amino acid residues e.g., between 210 and 300, between 230 and 300, between 250 and 300, between 270 and 300, between 290 and 300, between 210 and 290, between 220 and 280, between 230 and 270, between 240 and 260, or between 245 and 255 amino acid residues
  • the Fc domain monomer includes a serine at amino acid position 220, a tyrosine at position 252, a threonine at position 254, and/or a glutamic acid at position 256.
  • the Fc domain monomer includes a serine at amino acid position 220, an aspartic acid at position 309, a histidine at position 311, and/or a serine at position 434.
  • the Fc domain monomer further includes one or more (one, two, three, four, five, six, seven, eight, nine, ten or more) additional mutations (e.g., amino acid deletions, additions, and/or substitutions) relative to the corresponding human wild-type Fc sequence.
  • the Fc domain monomer includes a serine at amino acid position 220, wherein the amino acid numbering is according to the EU index as in Kabat, and wherein the Fc domain monomer is between about 20 kDa and about 40 kDa (e.g., 20 kDa to 25 kDa, 25 kDa to 30 kDa, 30 kDa to 35 kDa, 35 kDa to 40 kDa) in mass.
  • the Fc domain monomer includes a serine at amino acid position 220, a tyrosine at position 252, a threonine at position 254, and/or a glutamic acid at position 256.
  • the Fc domain monomer includes a serine at amino acid position 220, an aspartic acid at position 309, a histidine at position 311, and/or a serine at position 434.
  • the N-terminus of the Fc domain monomer includes between 10 and 20 residues (e.g., 11, 12, 13, 14, 15, 16, 17, 18, or 19 residues) of the Fab domain.
  • the N-terminus of the Fc domain monomer is any one of amino acid residues 198-205.
  • the N-terminus of the Fc domain monomer is amino acid residue 201 (e.g., Asn 201).
  • the N-terminus of the Fc domain monomer is amino acid residue 202 (e.g., Val 202).
  • the C-terminus of the variant Fc domain monomer is any one of amino acid residues 437-447.
  • the C-terminus of the variant Fc domain monomer is amino acid residue 446 (e.g., Gly 446).
  • the C-terminus of the variant Fc domain monomer is amino acid residue 447 (e.g. Lys 447).
  • the Fc domain containing composition includes an Fc domain including a dimer of Fc domain monomers each independently selected from any one of the Fc domain monomers described herein, where the Fc domain is between about 50 kDa and about 70 kDa (e.g., about 51 kDa, about 52 kDa, about 53 kDa, about 54 kDa, about 55 kDa, about 56 kDa, about 57 kDa, about 58 kDa, about 59 kDa, about 60 kDa, about 61 kDa, about 62 kDa, about 63 kDa, about 64 kDa, about 65 kDa, about 66 kDa, about 67 kDa, about 68 kDa, or about 69 kDa) in mass.
  • kDa and about 70 kDa e.g., about 51 kDa, about 52 kDa, about 53 kDa, about
  • the Fc domain monomer dimerizes (e.g., a homodimer or a heterodimer) to form a Fc domain.
  • the Fc domain is at least 40 kDa (e.g., at least 45 kDa, at least 50 kDa, at least 55 kDa, at least 60 kDa, at least 65 kDa, at least 70 kDa, at least 75 kDa, or at least 80 kDa).
  • the Fc domain is between 40 kDa and 80 kDa (e.g., between about 42 kDa and about 50 kDa, about 48 kDa and about 55 kDa, about 53 kDa about 60 kDa, about 58 kDa and about 65 kDa, about 62 kDa and about 70 kDa, about 68 kDa and about 75 kDa, or about 72 kDa and about 80 kDa) in mass.
  • 40 kDa and 80 kDa e.g., between about 42 kDa and about 50 kDa, about 48 kDa and about 55 kDa, about 53 kDa about 60 kDa, about 58 kDa and about 65 kDa, about 62 kDa and about 70 kDa, about 68 kDa and about 75 kDa, or about 72 kDa and about 80 kDa
  • the Fc domain is between 55 kDa and 62 kDa (e.g., about 56 kDa, about 57 kDa, about 58 kDa, about 59 kDa, about 60 kDa, or about 61 kDa).
  • the variant Fc domain is a homodimer including two Fc domain monomers (e.g., a homodimer in which each variant Fc domain monomer includes the sequence of any one of SEQ ID NOs: 1-138).
  • the Fc domain monomer includes an amino acid sequence at least 90% identical (e.g., at least 95%, at least 98%) to the sequence of any one of SEQ ID NOs: 1-138, or a region thereof.
  • a sulfur atom “corresponding to” a particular cysteine residue of a particular SEQ ID NO. should be understood to include the sulfur atom of any cysteine residue that one of skill in the art would understand to align to the particular cysteine of the particular sequence.
  • the protein sequence alignment of human IgG1 (UniProtKB: P01857; SEQ ID NO: 164), human IgG2 (UniProtKB: P01859; SEQ ID NO: 165), human IgG3 (UniProtKB: P01860; SEQ ID NO: 166), and human IgG4 (UniProtKB: P01861; SEQ ID NO: 167) is provided below (aligned with Clustal Omega Multiple Pairwise Alignment).
  • the alignment indicates cysteine residues (e.g., sulfur atoms of cysteine residues) that “correspond to” one another (in boxes and indicated by the • symbol).
  • Cys10 of SEQ ID NO: 10 corresponds to, for example, Cys109 of IgG1, Cys106 of IgG2, Cys156 of IgG3, Cys29 of SEQ ID NO: 1, Cys9 of SEQ ID NO: 2, Cys30 of SEQ ID NO: 3, or Cys10 of SEQ ID NO: 10.
  • the Fc domain or Fc domain monomer of the invention has the sequence of any one of SEQ ID NOs: 39-138 may further include additional amino acids at the N-terminus (Xaa)x and/or additional amino acids at the C-terminus (Xaa)z, wherein Xaa is any amino acid and x and z are a whole number greater than or equal to zero, generally less than 100, prefereably less than 10 and more preferably 0, 1, 2, 3, 4, or 5.
  • the additional amino acids are least 70% (e.g., 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100%) idential to one or more consecutive amino acids of SEQ ID NO: 94.
  • the additional amino acids may be a single amino aid on the C- terminus corresponding to Lys447 of IgG1 (SEQ ID NO: 161).
  • a nitrogen atom “corresponding to” a particular lysine residue of a particular SEQ ID NO. should be understood to include the nitrogen atom of any lysine residue that one of skill in the art would understand to align to the particular lysine of the particular sequence.
  • the protein sequence alignment of human IgG1 (UniProtKB: P01857; SEQ ID NO: 164), human IgG2 (UniProtKB: P01859; SEQ ID NO: 165), human IgG3 (UniProtKB: P01860; SEQ ID NO: 166), and human IgG4 (UniProtKB: P01861; SEQ ID NO: 167) is provided below (aligned with Clustal Omega Multiple Pairwise Alignment).
  • the alignment indicates lysine residues (e.g., nitrogen atoms of lysine residues) that “correspond to” one another (in boxes and indicated by the * symbol).
  • Lys35 of SEQ ID NO: 10 corresponds to, for example, Lys129 of IgG1, Lys126 of IgG2, Lys176 of IgG3, Lys51 of SEQ ID NO: 1, Lys31 of SEQ ID NO: 2, Lys50 of SEQ ID NO: 3, or Lys30 of SEQ ID NO: 10.
  • Fc-gamma receptors bind the Fc portion of immunoglobulin G (IgG) and play important roles in immune activation and regulation.
  • FcgRs Fc-gamma receptors
  • ICs immune complexes
  • the human FcgR family contains several activating receptors (FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb) and one inhibitory receptor (FcgRIIb).
  • FcgR signaling is mediated by intracellular domains that contain immune tyrosine activating motifs (ITAMs) for activating FcgRs and immune tyrosine inhibitory motifs (ITIM) for inhibitory receptor FcgRIIb.
  • ITAMs immune tyrosine activating motifs
  • ITIM immune tyrosine inhibitory motifs
  • FcgR binding by Fc domains results in ITAM phosphorylation by Src family kinases; this activates Syk family kinases and induces downstream signaling networks, which include PI3K and Ras pathways.
  • the portion of the conjugates including monomers or dimers of RSV F protein inhibitors bind to and inhibits viral RSV F protein leading to inhibition of viral replication, while the Fc domain portion of the conjugates bind to FcgRs (e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb) on immune cells and activate phagocytosis and effector functions, such as antibody-dependent cell-mediated cytotoxicity (ADCC), thus leading to the engulfment and destruction of viral particles by immune cells and further enhancing the antiviral activity of the conjugates.
  • FcgRs e.g., FcRn, FcgRI, FcgRIIa, FcgRIIc, FcgRIIIa, and FcgRIIIb
  • ADCC antibody-dependent cell-mediated cytotoxicity
  • immune cells that may be activated by the conjugates described herein include, but are not limited to, macrophages, neutrophils, eosinophils, basophils, lymphocytes, follicular dendritic cells, natural killer cells, and mast cells.
  • Tissue distribution After a therapeutic enters the systemic circulation, it is distributed to the body’s tissues. Distribution is generally uneven because of different in blood perfusion, tissue binding, regional pH, and permeability of cell membranes. The entry rate of a drug into a tissue depends on the rate of blood flow to the tissue, tissue mass, and partition characteristics between blood and tissue.
  • the conjugates described herein may be optimized to distribute to lung tissue.
  • the conjugates have a concentration ratio of distribution in epithelial lining fluid of at least 30% the concentration of the the conjugate in plasma within 2 hours after administration.
  • ratio of the concentration is at least 45% within 2 hours after administration.
  • the ratio of concentration is at least 55% within 2 hours after administration.
  • the ratio of concentration is at least 60% within 2 hours after administration.
  • a conjugate having an Fc domain (SEQ ID NO: 73) decorated with one or more small molecule antiviral inhibitors ELF levels are surprisingly ⁇ 60% of plasma exposure levels as measured by AUC across the rest of the time course indicating nearly immediate partitioning of the conjugate from plasma to the ELF in the lung.
  • An albumin protein of the invention may be a naturally-occurring albumin or a variant thereof, such as an engineered variant of a naturally-occurring albumin protein.
  • Variants include polymorphisms, fragments such as domains and sub-domains, and fusion proteins.
  • An albumin protein may include the sequence of an albumin protein obtained from any source. Preferably the source is mammalian, such as human or bovine. Most preferably, the albumin protein is human serum albumin (HSA), or a variant thereof. Human serum albumins includes any albumin protein having an amino acid sequence naturally occurring in humans, and variants thereof.
  • An albumin protein coding sequence is obtainable by methods know to those of skill in the art for isolating and sequencing cDNA corresponding to human genes.
  • An albumin protein of the invention may include the amino acid sequence of human serum albumin (HSA), provided in SEQ ID NO: 96 or SEQ ID NO: 97, or the amino acid sequence of mouse serum albumin (MSA), provided in SEQ ID NO: 98, or a variant or fragment thereof, preferably a functional variant or fragment thereof.
  • a fragment or variant may or may not be functional, or may retain the function of albumin to some degree.
  • a fragment or variant may retain the ability to bind to an albumin receptor, such as HSA or MSA, by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 105% of the ability of the parent albumin (e.g., the parent albumin from which the fragment or variant is derived).
  • the albumin protein may be a naturally-occurring polymorphic variant of an albumin protein, such as human serum albumin. Generally, variants or fragments of human serum albumin will have at least 5%, 10%, 15%, 20%, 30%, 40%, 50%, 60%, or 70%, and preferably 80%, 90%, 95%, 100%, or 105% or more of human serum albumin or mouse serum albumin’s ligand binding activity.
  • the albumin protein may include the amino acid sequence of bovine serum albumin.
  • Bovine serum albumin proteins include any albumin having an amino acid sequence naturally occurring in cows, for example, as described by Swissprot accession number P02769, and variants thereof as defined herein.
  • Bovine serum albumin proteins also includes fragments of full-length bovine serum albumin or variants thereof, as defined herein.
  • the albumin protein may include the sequence of an albumin derived from one of serum albumin from dog (e.g., Swissprot accession number P49822-1), pig (e.g., Swissprot accession number P08835- 1), goat (e.g., Sigma product no.
  • a 2 514 or A4164 cat (e.g., Swissprot accession number P49064-1), chicken (e.g., Swissprot accession number P19121-1), ovalbumin (e.g., chicken ovalbumin) (e.g., Swissprot accession number P01012-1), turkey ovalbumin (e.g., Swissprot accession number O73860-1), donkey (e.g., Swissprot accession number Q5XLE4-1), guinea pig (e.g., Swissprot accession number Q6WDN9-1), hamster (e.g., as described in DeMarco et al.
  • cat e.g., Swissprot accession number P49064-1
  • chicken e.g., Swissprot accession number P19121-1
  • ovalbumin e.g., chicken ovalbumin
  • Swissprot accession number P01012-1 e.g., Swissprot accession number P01012-1
  • turkey ovalbumin e
  • horse e.g., Swissprot accession number P35747-1
  • rhesus monkey e.g., Swissprot accession number Q28522-1
  • mouse e.g., Swissprot accession number P07724-1
  • pigeon e.g., as defined by Khan et al. Int. J. Biol. Macromol.30(3-4),171-8 (2002)
  • rabbit e.g., Swissprot accession number P49065-1
  • rat e.g., Swissprot accession number P02770-1
  • sheep e.g., Swissprot accession number P14639-1
  • albumin proteins of the invention include variants of naturally-occurring albumin proteins.
  • a variant albumin refers to an albumin protein having at least one amino acid mutation, such as an amino acid mutation generated by an insertion, deletion, or substitution, either conservative or non-conservative, provided that such changes result in an albumin protein for which at least one basic property has not been significantly altered (e.g., has not been altered by more than 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%).
  • Exemplary properties which may define the activity of an albumin protein include binding activity (e.g., including binding specificity or affinity to bilirubin, or a fatty acid such as a long-chain fatty acid), osmolarity, or behavior in a certain pH-range.
  • an albumin protein variant will have at least 40%, at least 50%, at least 60%, and preferably at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% amino acid sequence identity with a naturally-occurring albumin protein, such as the albumin protein of any one of SEQ ID NOs: 139-141.
  • Methods for the production and purification of recombinant human albumins are well-established (Sleep et al. Biotechnology, 8(1):42-6 (1990)), and include the production of recombinant human albumin for pharmaceutical applications (Bosse et al. J Clin Pharmacol 45(1):57-67 (2005)).
  • HSA three-dimensional structure of HSA has been elucidated by X-ray crystallography (Carter et al. Science. 244(4909): 1195-8(1998)); Sugio et al. Protein Eng.12(6):439-46 (1999)).
  • the HSA polypeptide chain has 35 cysteine residues, which form 17 disulfide bonds, and one unpaired (e.g., free) cysteine at position 34 of the mature protein. Cys-34 of HSA has been used for conjugation of molecules to albumin (Leger et al. Bioorg Med Chem Lett 14(17):4395-8 (2004); Thibaudeau et al. Bioconjug Chem 16(4):1000-8 (2005)), and provides a site for site-specific conjugation.
  • SEQ ID NO: 139 Human serum albumin (HSA), variant 1) DAHKSEVAHRFKDLGEENFKALVLIAFAQYLQQCPFEDHVKLVNEVTEFAKTCVADESAENCDKSLHTLF GDKLCTVATLRETYGEMADCCAKQEPERNECFLQHKDDNPNLPRLVRPEVDVMCTAFHDNEETFLKKYL YEIARRHPYFYAPELLFFAKRYKAAFTECCQAADKAACLLPKLDELRDEGKASSAKQRLKCASLQKFGER AFKAWAVARLSQRFPKAEFAEVSKLVTDLTKVHTECCHGDLLECADDRADLAKYICENQDSISSKLKECC EKPLLEKSHCIAEVENDEMPADLPSLAADFVESKDVCKNYAEAKDVFLGMFLYEYARRHPDYSVVLLLRL AKTYETTLEKCCAAADPHECYAKVFDEFKPLVEEPQNLIKQNCELFEQLGEYKFQNALLVRY
  • the albumin protein may be conjugated to any compound of the invention by any method well- known to those of skill in the art for producing small-molecule-protein conjugates. This may include covalent conjugation to a solvent-exposed amino acid, such as a solvent exposed cysteine or lysine.
  • human serum albumin may be conjugated to a compound of the invention by covalent linkage to the sulfur atom corresponding to Cys34 of SEQ ID NO: 136 or Cys40 of SEQ ID NO: 140.
  • An albumin protein of the invention may be conjugated to any compound of the invention by way of an amino acid located within 10 amino acid residues of the C-terminal or N-terminal end of the albumin protein.
  • An albumin protein may include a C-terminal or N-terminal polypeptide fusion of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 or more amino acid.
  • the C-terminal or N-terminal polypeptide fusion may include one or more solvent-exposed cysteine or lysine residues, which may be used for covalent conjugation of a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker).
  • Albumin proteins of the invention include any albumin protein which has been engineered to include one or more solvent-exposed cysteine or lysine residues, which may provide a site for conjugation to a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker). Most preferably, the albumin protein will contain a single solvent-exposed cysteine or lysine, thus enabling site-specific conjugation of a compound of the invention. Exemplary methods for the production of engineered variants of albumin proteins that include one or more conjugation-competent cysteine residues are provided in U.S. Patent Application No. 2017/0081389, which is incorporated herein by reference in its entirety.
  • albumin protein variants are those including a single, solvent-exposed, unpaired (e.g., free) cysteine residue, thus enabling site-specific conjugation of a linker to the cysteine residue.
  • Albumin proteins which have been engineered to enable chemical conjugation to a solvent- exposed, unpaired cysteine residue include the following albumin protein variants: (a) an albumin protein having a substitution of a non-cysteine amino acid residue with a cysteine at an amino acid residue corresponding to any of L585, D1, A 2 , D562, A364, A504, E505, T79, E86, D129, D549, A581, D121, E82, S270, Q397, and A578 of SEQ ID NO: 139; (b) an albumin protein having an insertion of a cysteine at a position adjacent the N- or C-terminal side of an amino acid residue corresponding to any of L585, D1, A 2 , D562, A364, A504, E505,
  • the net result of the substitution, deletion, addition, or insertion events of (a), (b), (c) and/or (d) is that the number of conjugation competent cysteine residues of the polypeptide sequence is increased relative to the parent albumin sequence.
  • the net result of the substitution, deletion, addition, or insertion events of (a), (b), (c) and/or (d) is that the number of conjugation competent-cysteine residues of the polypeptide sequence is one, thus enabling site-specific conjugation.
  • Preferred albumin protein variants also include albumin proteins having a single solvent-exposed lysine residue, thus enabling site-specific conjugation of a linker to the lysine residue.
  • Such variants may be generated by engineering an albumin protein, including any of the methods previously described (e.g., insertion, deletion, substitution, or C-terminal or N-terminal fusion).
  • Albumin protein-binding peptides Conjugation of a biologically-active compound to an albumin protein-binding peptide can alter the pharmacodynamics of the biologically-active compound, including the alteration of tissue uptake, penetration, and diffusion.
  • conjugation of an albumin protein-binding peptide to a compound of the invention e.g., a RSV F protein inhibitor monomer or dimer, by way of a linker
  • Albumin protein-binding peptides of the invention include any polypeptide having an amino acid sequence of 5 to 50 (e.g., 5 to 40, 5 to 30, 5 to 20, 5 to 15, 5 to 10, 10 to 50, 10 to 30, or 10 to 20) amino acid residues that has affinity for and functions to bind an albumin protein, such as any of the albumin proteins described herein.
  • the albumin protein-binding peptide binds to a naturally occurring serum albumin, most preferably human serum albumin.
  • An albumin protein-binding peptide can be of different origins, e.g., synthetic, human, mouse, or rat.
  • Albumin protein-binding peptides of the invention include albumin protein-binding peptides which have been engineered to include one or more (e.g., two, three, four, or five) solvent-exposed cysteine or lysine residues, which may provide a site for conjugation to a compound of the invention (e.g., conjugation to a RSV F protein inhibitor monomer or dimer, including by way of a linker).
  • the albumin protein-binding peptide will contain a single solvent-exposed cysteine or lysine, thus enabling site-specific conjugation of a compound of the invention.
  • Albumin protein-binding peptides may include only naturally occurring amino acid residues, or may include one or more non-naturally occurring amino acid residues. Where included, a non-naturally occurring amino acid residue (e.g., the side chain of a non-naturally occurring amino acid residue) may be used as the point of attachment for a compound of the invention (e.g., a RSV F protein inhibitor monomer or dimer, including by way of a linker). Albumin protein-binding peptides of the invention may be linear or cyclic. Albumin protein-binding peptides of the invention include any albumin protein-binding peptides known to one of skill in the art, examples of which, are provided herein.
  • Albumin protein-binding peptide and conjugates including an albumin protein-binding peptide, preferably bind an albumin protein (e.g., human serum albumin) with an affinity characterized by a dissociation constant, Kd, that is less than about 100 mM, preferably less than about 100 nM, and most preferably do not substantially bind other plasma proteins.
  • an albumin protein e.g., human serum albumin
  • Kd dissociation constant
  • Specific examples of such compounds are linear or cyclic peptides, preferably between about 10 and 20 amino acid residues in length, optionally modified at the N-terminus or C-terminus or both.
  • Albumin protein-binding peptides include linear and cyclic peptides including the following general formulae, wherein Xaa is any amino acid: SEQ ID NO: 144 Xaa-Xaa-Cys-Xaa-Xaa-Xaa-Xaa-Cys-Xaa-Xaa-Phe-Cys-Xaa-Asp-Trp-Pro-Xaa-Xaa-Xaa-Ser-Cys SEQ ID NO: 145 Val-Cys-Tyr-Xaa-Xaa-Xaa-Ile-Cys-Phe SEQ ID NO: 146 Cys-Tyr-Xaa-Pro-Gly-Xaa-Cys SEQ ID NO: 147 Asp-Xaa-Cys-Leu-Pro-Xaa-Trp-Gly-Cys-Leu-Trp SEQ ID NO: 148 Trp-Cys-
  • albumin protein-binding peptides are provided in U.S. Patent Application No. 2005/0287153, which is incorporated herein by reference in its entirety.
  • Conjugation of albumin protein-binding peptides An albumin protein-binding peptide of the invention may be conjugated to (e.g., by way of a covalent bond) to any compound of the invention (e.g., by way of the linker portion of a RSV F protein inhibitor monomer or dimer).
  • the albumin protein-binding peptide may be conjugated to any compound of the invention by any method known to those of skill in the art for producing peptide-small molecule conjugates.
  • This may include covalent conjugation to the side chain group of an amino acid residue, such as a cysteine, a lysine, or a non-natural amino acid.
  • covalent conjugation may occur at the C-terminus (e.g., to the C-terminal carboxylic acid, or to the side chain group of the C-terminal residue) or at the N-terminus (e.g., to the N-terminal amino group, or to the side chain group of the N- terminal amino acid).
  • Linkers A linker refers to a linkage or connection between two or more components in a conjugate described herein (e.g., between two RSV F protein inhibitors in a conjugate described herein, between a RSV F protein inhibitor and an Fc domain or an albumin protein in a conjugate described herein, and between a dimer of two RSV F protein inhibitors and an Fc domain or an albumin protein in a conjugate described herein).
  • Linkers in conjugates having an Fc domain or an albumin protein covalently linked to dimers of RSV F protein inhibitors In a conjugate containing an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide covalently linked to one or more dimers of RSV F protein inhibitors as described herein, a linker in the conjugate (e.g., L or L’) may be a branched structure. As described further herein, a linker in a conjugate described herein (e.g., L or L’) may be a multivalent structure, e.g., a divalent or trivalent structure having two or three arms, respectively.
  • the linker when the linker has three arms, two of the arms may be attached to the first and second RSV F protein inhibitors and the third arm may be attached to the Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide. In some embodiments when the linker has two arms, one arm may be attached to an Fc domain or an albumin protein and the other arm may be attached to one of the two RSV F protein inhibitors. In other embodiments, a linker with two arms may be used to attach the two RSV F protein inhibitors on a conjugate containing an Fc domain or albumin protein covalently linked to one or more dimers of RSV F protein inhibitors.
  • a linker in a conjugate having an Fc domain or an albumin protein covalently linked to one or more dimers of RSV F protein inhibitors is described by formula (D-L-I): (D-L-I) wherein L A is described by formula G A1 -(Z A1 )g1-(Y A1 )h1-(Z A2 )i1-(Y A2 )j1-(Z A3 )k1-(Y A3 )l1-(Z A4 )m1-(Y A4 )n1-(Z A5 )o1- G A2 ; L B is described by formula G B1 -(Z B1 )g2-(Y B1 )h2-(Z B2 )i2-(Y B2 )j2-(Z B3 )k2-(Y B3 )l2-(Z B4 )m2-(Y B4 )n2-(Z B5 )o2-G B2 ; L C is described by formula G C
  • optionally substituted includes substitution with a PEG.
  • a PEG has a repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5-PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60-PEG70, PEG70-PEG80, PEG80-PEG90, PEG90-PEG100).
  • L C may have two points of attachment to the Fc domain (e.g., two G C2 ).
  • L includes a polyethylene glycol (PEG) linker.
  • a PEG linker includes a linker having the repeating unit structure (-CH 2 CH 2 O-)n, where n is an integer from 2 to 100.
  • a polyethylene glycol linker may covalently join a RSV F protein inhibitor and E (e.g., in a conjugate of any one of formulas (M-I)-(M-IV)).
  • a polyethlylene glycol linker may covalently join a first RSV F protein inhibitor and a second RSV F protein inhibitor (e.g., in a conjugate of any one of formulas (D-I)-(D-VII)).
  • a polyethylene glycol linker may covalently join a RSV F protein inhibitor dimer and E (e.g., in a conjugate of any one of formulas (D-I)-(D-VII)).
  • a polyethylene glycol linker may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5-PEG10, PEG10-PEG20, PEG20-PEG30, PEG30-PEG40, PEG50-PEG60, PEG60-PEG70, PEG70-PEG80, PEG80-PEG90, PEG90-PEG100).
  • L c includes a PEG linker, where L C is covalently attached to each of Q i and E.
  • Linkers in conjugates having an Fc domain or an albumin protein covalently linked to monomers of RSV F protein inhibitors In a conjugate containing an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide covalently linked to one or more monomers of RSV F protein inhibitors as described herein, a linker in the conjugate (e.g., L, or L’) may be a divalent structure having two arms.
  • One arm in a divalent linker may be attached to the monomer of RSV F protein inhibitor and the other arm may be attached to the Fc domain monomer, and Fc domain, an Fc- binding peptide, an albumin protein, or an albumin protein-binding peptide.
  • the one or more monomers of RSV F protein inhibitors in the conjugates described herein may each be, independently, connected to an atom in the Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide.
  • a linker is described by formula (M-L-I): J 1 -(Q 1 )g-(T 1 )h-(Q 2 )i-(T 2 )j-(Q 3 )k-(T 3 )l-(Q 4 )m-(T 4 )n-(Q 5 )o-J 2 wherein J 1 is a bond attached to a RSV F protein inhibitor; J 2 is a bond attached to an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide, or a functional group capable of reacting with a functional group conjugated to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide (e.g., maleimide and cysteine, amine and activated carboxylic acid, thiol and maleimide, activated sulfonic acid and amine,
  • optionally substituted includes substitution with a polyethylene glycol (PEG).
  • PEG polyethylene glycol
  • a PEG has a repeating unit structure (-CH 2 CH 2 O-)n, wherein n is an integer from 2 to 100.
  • a polyethylene glycol may selected any one of PEG2 to PEG100 (e.g., PEG2, PEG3, PEG4, PEG5, PEG5- PEG 10 , PEG 10 -PEG 20 , PEG 20 -PEG 30 , PEG 30 -PEG 40 , PEG 50 -PEG 60 , PEG 60 -PEG 70 , PEG 70 -PEG 80 , PEG 80 - PEG90, PEG90-PEG100).
  • PEG2 to PEG100 e.g., PEG2, PEG3, PEG4, PEG5, PEG5- PEG 10 , PEG 10 -PEG 20 , PEG 20 -PEG 30 , PEG 30 -PEG 40 , PEG 50 -
  • J 2 may have two points of attachment to the Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide (e.g., two J 2 ).
  • Linking groups In some embodiments, a linker provides space, rigidity, and/or flexibility between the RSV F protein inhibitors and the Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide in the conjugates described here or between two RSV F protein inhibitors in the conjugates described herein.
  • a linker may be a bond, e.g., a covalent bond, e.g., an amide bond, a disulfide bond, a C-O bond, a C-N bond, a N-N bond, a C-S bond, or any kind of bond created from a chemical reaction, e.g., chemical conjugation.
  • a covalent bond e.g., an amide bond, a disulfide bond, a C-O bond, a C-N bond, a N-N bond, a C-S bond, or any kind of bond created from a chemical reaction, e.g., chemical conjugation.
  • a linker (L or L’ as shown in any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII) includes no more than 250 atoms (e.g., 1-2, 1-4, 1-6, 1-8, 1-10, 1-12, 1-14, 1-16, 1-18, 1-20, 1-25, 1-30, 1-35, 1-40, 1-45, 1-50, 1-55, 1-60, 1-65, 1-70, 1-75, 1-80, 1-85, 1-90, 1-95, 1-100, 1-110, 1-120, 1-130, 1- 140, 1-150, 1-160, 1-170, 1-180, 1-190, 1-200, 1-210, 1-220, 1-230, 1-240, or 1-250 atom(s); 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50,
  • a linker includes no more than 250 non-hydrogen atoms (e.g., 1-2, 1-4, 1-6, 1-8, 1- 10, 1-12, 1-14, 1-16, 1-18, 1-20, 1-25, 1-30, 1-35, 1-40, 1-45, 1-50, 1-55, 1-60, 1-65, 1-70, 1-75, 1-80, 1- 85, 1-90, 1-95, 1-100, 1-110, 1-120, 1-130, 1-140, 1-150, 1-160, 1-170, 1-180, 1-190, 1-200, 1-210, 1- 220, 1-230, 1-240, or 1-250 non-hydrogen atom(s); 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 non-hydrogen atom(s); 250,
  • the backbone of a linker includes no more than 250 atoms (e.g., 1-2, 1-4, 1-6, 1-8, 1-10, 1-12, 1-14, 1-16, 1-18, 1- 20, 1-25, 1-30, 1-35, 1-40, 1-45, 1-50, 1-55, 1-60, 1-65, 1-70, 1-75, 1-80, 1-85, 1-90, 1-95, 1-100, 1-110, 1-120, 1-130, 1-140, 1-150, 1-160, 1-170, 1-180, 1-190, 1-200, 1-210, 1-220, 1-230, 1-240, or 1-250 atom(s); 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 atom(s)).
  • the “backbone” of a linker refers to the atoms in the linker that together form the shortest path from one part of the conjugate to another part of the conjugate.
  • the atoms in the backbone of the linker are directly involved in linking one part of the conjugate to another part of the conjugate.
  • hydrogen atoms attached to carbons in the backbone of the linker are not considered as directly involved in linking one part of the conjugate to another part of the conjugate.
  • Molecules that may be used to make linkers (L or L’) include at least two functional groups, e.g., two carboxylic acid groups.
  • two arms of a linker may contain two dicarboxylic acids, in which the first carboxylic acid may form a covalent linkage with the first RSV F protein inhibitor in the conjugate and the second carboxylic acid may form a covalent linkage with the second RSV F protein inhibitor in the conjugate, and the third arm of the linker may for a covalent linkage (e.g., a C-O bond) with an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide in the conjugate.
  • a covalent linkage e.g., a C-O bond
  • the divalent linker may contain two carboxylic acids, in which the first carboxylic acid may form a covalent linkage with one component (e.g., a RSV F protein inhibitor) in the conjugate and the second carboxylic acid may form a covalent linkage (e.g., a C-S bond or a C-N bond) with another component (e.g., an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein- binding peptide) in the conjugate.
  • dicarboxylic acid molecules may be used as linkers (e.g., a dicarboxylic acid linker).
  • the first carboxylic acid in a dicarboxylic acid molecule may form a covalent linkage with a hydroxyl or amine group of the first RSV F protein inhibitor and the second carboxylic acid may form a covalent linkage with a hydroxyl or amine group of the second RSV F protein inhibitor.
  • dicarboxylic acids molecules that may be used to form linkers include, but are not limited to,
  • n is an integer from 1 to 20 (e.g., n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20).
  • dicarboxylic acids molecules that may be used to form linkers include, but are not limited to, ,
  • dicarboxylic acid molecules such as the ones described herein, may be further functionalized to contain one or more additional functional groups.
  • Dicarboxylic acids may be further functionalized, for example, to provide an attachment point to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide (e.g., by way of a linker, such as a PEG linker).
  • the linking group may include a moiety including a carboxylic acid moiety and an amino moiety that are spaced by from 1 to 25 atoms. Examples of such linking groups include, but are not limited to,
  • n is an integer from 1 to 20 (e.g., n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20).
  • a linking group may including a moiety including a carboxylic acid moiety and an amino moiety, such as the ones described herein, may be further functionalized to contain one or more additional functional groups.
  • Such linking groups may be further functionalized, for example, to provide an attachment point to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide (e.g., by way of a linker, such as a PEG linker).
  • the linking group may include a moiety including two or amino moieties (e.g., a diamino moiety) that are spaced by from 1 to 25 atoms.
  • Examples of such linking groups include, but are not limited to,
  • n is an integer from 1 to 20 (e.g., n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20).
  • a linking group may including a diamino moiety, such as the ones described herein, may be further functionalized to contain one or more additional functional groups.
  • Such diamino linking groups may be further functionalized, for example, to provide an attachment point to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein- binding peptide (e.g., by way of a linker, such as a PEG linker).
  • a molecule containing an azide group may be used to form a linker, in which the azide group may undergo cycloaddition with an alkyne to form a 1,2,3-triazole linkage.
  • a molecule containing an alkyne group may be used to form a linker, in which the alkyne group may undergo cycloaddition with an azide to form a 1,2,3-triazole linkage.
  • a molecule containing a maleimide group may be used to form a linker, in which the maleimide group may react with a cysteine to form a C-S linkage.
  • a molecule containing one or more haloalkyl groups may be used to form a linker, in which the haloalkyl group may form a covalent linkage, e.g., C-N and C-O linkages, with a RSV F protein inhibitor.
  • a linker (L or L’) may include a synthetic group derived from, e.g., a synthetic polymer (e.g., a polyethylene glycol (PEG) polymer).
  • a linker may include one or more amino acid residues.
  • a linker may be an amino acid sequence (e.g., a 1-25 amino acid, 1-10 amino acid, 1-9 amino acid, 1-8 amino acid, 1-7 amino acid, 1-6 amino acid, 1-5 amino acid, 1-4 amino acid, 1-3 amino acid, 1-2 amino acid, or 1 amino acid sequence).
  • a linker may include one or more optionally substituted C 1 -C 20 alkylene, optionally substituted C 1 -C 20 heteroalkylene (e.g., a PEG unit), optionally substituted C 2 -C 20 alkenylene (e.g., C2 alkenylene), optionally substituted C 2 -C 20 heteroalkenylene, optionally substituted C 2 -C 20 alkynylene, optionally substituted C 2 -C 20 heteroalkynylene, optionally substituted C3-C20 cycloalkylene (e.g., cyclopropylene, cyclobutylene), optionally substituted C 2 -C 20 heterocycloalkylene, optionally substituted C 4 -C 20 cycloalkenylene, optionally substituted C 4 -C 20 heterocycloalkenylene, optionally substituted C 8 -C 20 cycloalkynylene, optionally substituted C 8 -C 20 heterocycl
  • RSV F protein inhibitor monomers or dimers may be conjugated to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide, e.g., by way of a linker, by any standard conjugation chemistries known to those of skill in the art.
  • conjugation chemistries are specifically contemplated, e.g., for conjugation of a PEG linker (e.g., a functionalized PEG linker) to an Fc domain monomer, an Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein- binding peptide.
  • a PEG linker e.g., a functionalized PEG linker
  • Covalent conjugation of two or more components in a conjugate using a linker may be accomplished using well-known organic chemical synthesis techniques and methods. Complementary functional groups on two components may react with each other to form a covalent bond.
  • complementary reactive functional groups include, but are not limited to, e.g., maleimide and cysteine, amine and activated carboxylic acid, thiol and maleimide, activated sulfonic acid and amine, isocyanate and amine, azide and alkyne, and alkene and tetrazine.
  • Site-specific conjugation to a polypeptide e.g., an Fc domain monomer, and Fc domain, an Fc-binding peptide, an albumin protein, or an albumin protein-binding peptide
  • Exemplary techniques for site-specific conjugation of a small molecule to an Fc domain are provided in Agarwall. P., et al.
  • amino-reactive acylating groups include, e.g., (i) an isocyanate and an isothiocyanate; (ii) a sulfonyl chloride; (iii) an acid halide; (iv) an active ester, e.g., a nitrophenylester or N- hydroxysuccinimidyl ester; (v) an acid anhydride, e.g., a mixed, symmetrical, or N-carboxyanhydride; (vi) an acylazide; and (vii) an imidoester. Aldehydes and ketones may be reacted with amines to form Schiff’s bases, which may be stabilized through reductive amination.
  • a linker of the invention e.g., L or L’, such as L C of D-L-I
  • E e.g., an Fc domain or albumin protein
  • a linker e.g., an active ester, e.g., a nitrophenylester or N- hydroxysuccinimidyl ester, or derivatives thereof (e.g., a funtionalized PEG linker (e.g., azido-PEG2- PEG40-NHS ester)
  • a T of e.g., DAR
  • 0.5 and 10.0 e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2
  • the E-(PEG2-PEG40)-azide can react with an Int having a terminal alkyne linker (e.g., L, or L’, such as L C of D-L-I) through click conjugation.
  • an Int having a terminal alkyne linker e.g., L, or L’, such as L C of D-L-I
  • the copper-catalyzed reaction of the an azide (e.g., the Fc-(PEG2-PEG40)-azide) with the alkyne (e.g., the Int having a terminal alkyne linker (e.g., L or L’, such as L C of D-L-I) forming a 5-membered heteroatom ring.
  • the linker conjugated to E is a terminal alkyne and is conjugated to an Int having a terminal azide.
  • Exemplary preparations of preparations of E-(PEG2-PEG40)-azide are described in Examples 2, 3, and 12.
  • One of skill in the art would readily understand the final product from a click chemistry conjugation.
  • Exemplary linking strategies e.g., methods for linking a monomer or a dimer of a neuraminidase inhibitor to E, such as, by way of a linker are further depicted in FIGS.1-4. VI.
  • one or more antiviral agents may be administered in combination (e.g., administered substantially simultaneously (e.g., in the same pharmaceutical composition or in separate pharmaceutical compositions, or administered separately at different times) with a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • the antiviral agent is an antiviral agent for the treatment of RSV.
  • the antiviral agent may be a viral replication inhibitor, a RSV F protein inhibitor, a polymerase inhibitor, or a fusion protein inhibitor.
  • the antiviral agent may target either the virus or the host subject.
  • the antiviral agent for the treatment of RSV used in combination with a conjugate described herein may be selected from Presatovir, MDT 637, JNJ 179, TMC353121, or Ziresovir.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • Presatovir may be selected from Presatovir, MDT 637, JNJ 179, TMC353121, or Ziresovir.
  • derivatives of Presatovir, MDT 637, JNJ 179, TMC353121, or Ziresovir such as those found in the literature, have RSV F protein inhibitor activity and are useful as RSV F protein inhibitors in combination with the compounds herein (see, for example, Cockerill et al. J. Med.
  • any one of conjugates described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • an antiviral vaccine e.g., a composition that elicits an immune response in a subject directed against a virus.
  • the antiviral vaccine may be administered substantially simultaneously (e.g., in the same pharmaceutical composition or in separate pharmaceutical compositions) as the conjugates, or may be administered prior to or following the conjugates (e.g., within a period of 1 day, 2, days, 5, days, 1 week, 2 weeks, 3 weeks, 1 month, 2 months, 6 months, or 12 months, or more).
  • the viral vaccine includes an immunogen that elicits an immune response in the subject against RSV A or RSV B.
  • the vaccine is administered as a nasal spray. VII.
  • Methods described herein include, e.g., methods of protecting against or treating a viral infection (e.g., an RSV infection) in a subject and methods of preventing, stabilizing, or inhibiting the growth of viral particles.
  • a method of treating a viral infection (e.g., an RSV infection) in a subject includes administering to the subject a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) or a pharmaceutical composition thereof.
  • the viral infection is cause by the respiratory synctitial virus (e.g., RSV A or RSV B).
  • the viral infection is caused by a resistant strain of virus.
  • a method of preventing, stabilizing, or inhibiting the growth of viral particles or preventing the replication and spread of the virus includes contacting the virus or a site susceptible to viral growth with a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) or a pharmaceutical composition thereof.
  • methods described herein also include methods of protecting against or treating viral infection in a subject by administering to the subject a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)).
  • the method further includes administering to the subject an antiviral agent or an antiviral vaccine.
  • Methods described herein also include methods of protecting against or treating a viral infection in a subject by administering to said subject (1) a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) and (2) an antiviral agent or an antiviral vaccine.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • Methods described herein also include methods of preventing, stabilizing, or inhibiting the growth of viral particles or preventing the replication or spread of a virus, by contacting the virus or a site susceptible to viral growth with (1) a conjugate described herein (e.g., a conjugate of any one of formulas (1), (2), (D-I)- (D-VII), or (M-I)-(M-VII)) and (2) an antiviral agent or an antiviral vaccine.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)- (D-VII), or (M-I)-(M-VII)
  • the conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • the conjugate described herein is administered first, followed by administering of the antiviral agent or antiviral vaccine alone.
  • the antiviral agent or antiviral vaccine is administered first, followed by administering of the conjugate described herein alone.
  • the conjugate described herein and the antiviral agent or antiviral vaccine are administered substantially simultaneously (e.g., in the same pharmaceutical composition or in separate pharmaceutical compositions).
  • the conjugate described herein or the antiviral agent or antiviral vaccine is administered first, followed by administering of the conjugate described herein and the antiviral agent or antiviral vaccine substantially simultaneously (e.g., in the same pharmaceutical composition or in separate pharmaceutical compositions). In some embodiments, the conjugate described herein and the antiviral agent or antiviral vaccine are administered first substantially simultaneously (e.g., in the same pharmaceutical composition or in separate pharmaceutical compositions), followed by administering of the conjugate described herein or the antiviral agent or antiviral vaccine alone.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M- I)-(M-VII)
  • an antiviral agent or antiviral vaccine when administered together (e.g., substantially simultaneously in the same or separate pharmaceutical compositions, or separately in the same treatment regimen), inhibition of viral replication of each of the conjugate and the antiviral agent or antiviral vaccine may be greater (e.g., occur at a lower concentration) than inhibition of viral replication of each of the conjugate and the antiviral agent or antiviral vaccine when each is used alone in a treatment regimen.
  • a conjugate described herein may be formulated in a pharmaceutical composition for use in the methods described herein.
  • a conjugate described herein may be formulated in a pharmaceutical composition alone.
  • a conjugate described herein may be formulated in combination with an antiviral agent or antiviral vaccine in a pharmaceutical composition.
  • the pharmaceutical composition includes a conjugate described herein (e.g., a conjugate described by any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) and pharmaceutically acceptable carriers and excipients. Acceptable carriers and excipients in the pharmaceutical compositions are nontoxic to recipients at the dosages and concentrations employed.
  • Acceptable carriers and excipients may include buffers such as phosphate, citrate, HEPES, and TAE, antioxidants such as ascorbic acid and methionine, preservatives such as hexamethonium chloride, octadecyldimethylbenzyl ammonium chloride, resorcinol, and benzalkonium chloride, proteins such as human serum albumin, gelatin, dextran, and immunoglobulins, hydrophilic polymers such as polyvinylpyrrolidone, amino acid residues such as glycine, glutamine, histidine, and lysine, and carbohydrates such as glucose, mannose, sucrose, and sorbitol.
  • buffers such as phosphate, citrate, HEPES, and TAE
  • antioxidants such as ascorbic acid and methionine
  • preservatives such as hexamethonium chloride, octadecyldimethylbenzyl ammonium chloride,
  • excipients examples include, but are not limited to, antiadherents, binders, coatings, compression aids, disintegrants, dyes, emollients, emulsifiers, fillers (diluents), film formers or coatings, flavors, fragrances, glidants (flow enhancers), lubricants, sorbents, suspensing or dispersing agents, or sweeteners.
  • excipients include, but are not limited to: butylated hydroxytoluene (BHT), calcium carbonate, calcium phosphate (dibasic), calcium stearate, croscarmellose, crosslinked polyvinyl pyrrolidone, citric acid, crospovidone, cysteine, ethylcellulose, gelatin, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, maltitol, mannitol, methionine, methylcellulose, methyl paraben, microcrystalline cellulose, polyethylene glycol, povidone, pregelatinized starch, propyl paraben, retinyl palmitate, shellac, silicon dioxide, sodium carboxymethyl cellulose, sodium citrate, sodium starch glycolate, sorbitol, starch (corn), stearic acid, stearic acid, sucrose, talc, titanium dioxide, vitamin A, vitamin E, vitamin C, and xylit
  • the conjugates herein may have ionizable groups so as to be capable of preparation as pharmaceutically acceptable salts.
  • These salts may be acid addition salts involving inorganic or organic acids or the salts may, in the case of acidic forms of the conjugates herein be prepared from inorganic or organic bases.
  • the conjugates are prepared or used as pharmaceutically acceptable salts prepared as addition products of pharmaceutically acceptable acids or bases.
  • Suitable pharmaceutically acceptable acids and bases are well-known in the art, such as hydrochloric, sulphuric, hydrobromic, acetic, lactic, citric, or tartaric acids for forming acid addition salts, and potassium hydroxide, sodium hydroxide, ammonium hydroxide, caffeine, various amines, and the like for forming basic salts.
  • Representative acid addition salts include, but are not limited to, acetate, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptonate, glycerophosphate, hemisulfate, heptonate, hexanoate, hydrobromide, hydrochloride, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, n
  • alkali or alkaline earth metal salts include, but are not limited to, sodium, lithium, potassium, calcium, and magnesium, as well as nontoxic ammonium, quaternary ammonium, and amine cations, including, but not limited to ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, and ethylamine.
  • a conjugate herein or a pharmaceutical composition thereof used in the methods described herein will be formulated into suitable pharmaceutical compositions to permit facile delivery.
  • a conjugate e.g., a conjugate of any one of formulas (1), (2), (D- I)-(D-VII), or (M-I)-(M-VII)
  • a pharmaceutical composition thereof may be formulated to be administered intramuscularly, intravenously (e.g., as a sterile solution and in a solvent system suitable for intravenous use), intradermally, intraarterially, intraperitoneally, intralesionally, intracranially, intraarticularly, intraprostatically, intrapleurally, intratracheally, intranasally, intravitreally, intravaginally, intrarectally, topically, intratumorally, peritoneally, subcutaneously, subconjunctival, intravesicularlly, mucosally, intrapericardially, intraumbilically, intraocularally, orally (e.g., a tablet, capsule, caplet, gelcap, or syrup), topically (e.g., as a cream, gel, lotion, or o
  • a conjugate herein or a pharmaceutical composition thereof may be in the form of, e.g., tablets, capsules, pills, powders, granulates, suspensions, emulsions, solutions, gels including hydrogels, pastes, ointments, creams, plasters, drenches, osmotic delivery devices, suppositories, enemas, injectables, implants, sprays, preparations suitable for iontophoretic delivery, or aerosols.
  • the compositions may be formulated according to conventional pharmaceutical practice.
  • a conjugate described herein may be formulated in a variety of ways that are known in the art.
  • a conjugate described herein can be formulated as pharmaceutical or veterinary compositions.
  • a conjugate described herein is formulated in ways consonant with these parameters.
  • a summary of such techniques is found in Remington: The Science and Practice of Pharmacy, 22nd Edition, Lippincott Williams & Wilkins (2012); and Encyclopedia of Pharmaceutical Technology, 4th Edition, J. Swarbrick and J. C. Boylan, Marcel Dekker, New York (2013), each of which is incorporated herein by reference.
  • Formulations may be prepared in a manner suitable for systemic administration or topical or local administration.
  • Systemic formulations include those designed for injection (e.g., intramuscular, intravenous or subcutaneous injection) or may be prepared for transdermal, transmucosal, or oral administration.
  • the formulation will generally include a diluent as well as, in some cases, adjuvants, buffers, and preservatives.
  • the conjugates can be administered also in liposomal compositions or as microemulsions.
  • Systemic administration may also include relatively noninvasive methods such as the use of suppositories, transdermal patches, transmucosal delivery and intranasal administration.
  • Oral administration is also suitable for conjugates herein. Suitable forms include syrups, capsules, and tablets, as is understood in the art.
  • compositions can be administered parenterally in the form of an injectable formulation.
  • Pharmaceutical compositions for injection can be formulated using a sterile solution or any pharmaceutically acceptable liquid as a vehicle.
  • Formulations may be prepared as solid forms suitable for solution or suspension in liquid prior to injection or as emulsions.
  • Pharmaceutically acceptable vehicles include, but are not limited to, sterile water, physiological saline, and cell culture media (e.g., Dulbecco’s Modified Eagle Medium (DMEM), a-Modified Eagles Medium (a-MEM), F-12 medium).
  • Such injectable compositions may also contain amounts of nontoxic auxiliary substances such as wetting or emulsifying agents, pH buffering agents, such as sodium acetate and sorbitan monolaurate.
  • Formulation methods are known in the art, see e.g., Pharmaceutical Preformulation and Formulation, 2nd Edition, M. Gibson, Taylor & Francis Group, CRC Press (2009).
  • the pharmaceutical compositions can be prepared in the form of an oral formulation.
  • Formulations for oral use include tablets containing the active ingredient(s) in a mixture with non-toxic pharmaceutically acceptable excipients.
  • excipients may be, for example, inert diluents or fillers (e.g., sucrose, sorbitol, sugar, mannitol, microcrystalline cellulose, starches including potato starch, calcium carbonate, sodium chloride, lactose, calcium phosphate, calcium sulfate, or sodium phosphate); granulating and disintegrating agents (e.g., cellulose derivatives including microcrystalline cellulose, starches including potato starch, croscarmellose sodium, alginates, or alginic acid); binding agents (e.g., sucrose, glucose, sorbitol, acacia, alginic acid, sodium alginate, gelatin, starch, pregelatinized starch, microcrystalline cellulose, magnesium aluminum silicate, carboxymethylcellulose sodium, methylcellulose, hydroxypropyl methylcellulose, ethylcellulose, polyvinylpyrrolidone, or polyethylene glycol); and lubricating agents, glidants, and antiad
  • Formulations for oral use may also be provided as chewable tablets, or as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent (e.g., potato starch, lactose, microcrystalline cellulose, calcium carbonate, calcium phosphate or kaolin), or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example, peanut oil, liquid paraffin, or olive oil.
  • an inert solid diluent e.g., potato starch, lactose, microcrystalline cellulose, calcium carbonate, calcium phosphate or kaolin
  • water or an oil medium for example, peanut oil, liquid paraffin, or olive oil.
  • Powders, granulates, and pellets may be prepared using the ingredients mentioned above under tablets and capsules in a conventional manner using, e.g., a mixer, a fluid bed apparatus or a spray drying equipment.
  • Formulations for oral use may also be provided as chewable tablets, or as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent (e.g., potato starch, lactose, microcrystalline cellulose, calcium carbonate, calcium phosphate or kaolin), or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example, peanut oil, liquid paraffin, or olive oil.
  • an inert solid diluent e.g., potato starch, lactose, microcrystalline cellulose, calcium carbonate, calcium phosphate or kaolin
  • an oil medium for example, peanut oil, liquid paraffin, or olive oil.
  • Powders, granulates, and pellets may be prepared using the ingredients mentioned above under tablets and capsules in a conventional manner using, e.g., a mixer, a fluid bed apparatus or a spray drying equipment.
  • Dissolution or diffusion controlled release of a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • a pharmaceutical composition thereof can be achieved by appropriate coating of a tablet, capsule, pellet, or granulate formulation of the conjugate, or by incorporating the conjugate into an appropriate matrix.
  • a controlled release coating may include one or more of the coating substances mentioned above and/or, e.g., shellac, beeswax, glycowax, castor wax, carnauba wax, stearyl alcohol, glyceryl monostearate, glyceryl distearate, glycerol palmitostearate, ethylcellulose, acrylic resins, dl-polylactic acid, cellulose acetate butyrate, polyvinyl chloride, polyvinyl acetate, vinyl pyrrolidone, polyethylene, polymethacrylate, methylmethacrylate, 2-hydroxymethacrylate, methacrylate hydrogels, 1,3 butylene glycol, ethylene glycol methacrylate, and/or polyethylene glycols.
  • shellac beeswax, glycowax, castor wax, carnauba wax, stearyl alcohol, glyceryl monostearate, glyceryl distearate, glyce
  • the matrix material may also include, e.g., hydrated methylcellulose, carnauba wax and stearyl alcohol, carbopol 934, silicone, glyceryl tristearate, methyl acrylate-methyl methacrylate, polyvinyl chloride, polyethylene, and/or halogenated fluorocarbon.
  • the pharmaceutical composition may be formed in a unit dose form as needed.
  • conjugates herein may be administered by any appropriate route for treating or protecting against a viral infection (e.g., an RSV infection), or for preventing, stabilizing, or inhibiting the proliferation or spread of a virus (e.g., an RSV virus).
  • a viral infection e.g., an RSV infection
  • a virus e.g., an RSV virus
  • Conjugates described herein may be administered to humans, domestic pets, livestock, or other animals with a pharmaceutically acceptable diluent, carrier, or excipient.
  • administering includes administration of any of the conjugates described herein (e.g., conjugates of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)) or compositions intramuscularly, intravenously (e.g., as a sterile solution and in a solvent system suitable for intravenous use), intradermally, intraarterially, intraperitoneally, intralesionally, intracranially, intraarticularly, intraprostatically, intrapleurally, intratracheally, intranasally, intravitreally, intravaginally, intrarectally, topically, intratumorally, peritoneally, subcutaneously, subconjunctival, intravesicularlly, mucosally, intrapericardially, intraumbilically, intraocularally, or
  • an antiviral agent if an antiviral agent is also administered in addition to a conjugate described herein, the antiviral agent or a pharmaceutical composition thereof may also be administered in any of the routes of administration described herein.
  • the dosage of a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D- I)-(D-VII), or (M-I)-(M-VII)
  • pharmaceutical compositions thereof depends on factors including the route of administration, the disease to be treated (e.g., the extent and/or condition of the viral infection), and physical characteristics, e.g., age, weight, general health, of the subject.
  • the amount of the conjugate or the pharmaceutical composition thereof contained within a single dose may be an amount that effectively prevents, delays, or treats the viral infection without inducing significant toxicity.
  • a pharmaceutical composition may include a dosage of a conjugate described herein ranging from 0.01 to 500 mg/kg (e.g., 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500 mg/kg) and, in a more specific embodiment, about 0.1 to about 30 mg/kg and, in a more specific embodiment, about 1 to about 30 mg/kg.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M- VII)
  • an antiviral agent or antiviral vaccine are administered in combination (e.g., substantially simultaneously in the same or separate pharmaceutical compositions, or separately in the same treatment regimen)
  • the dosage needed of the conjugate described herein may be lower than the dosage needed of the conjugate if the conjugate was used alone in a treatment regimen.
  • a conjugate described herein e.g., a conjugate of any one of formulas (1), (2), (D-I)-(D-VII), or (M-I)-(M-VII)
  • a pharmaceutical composition thereof may be administered to a subject in need thereof, for example, one or more times (e.g., 1-10 times or more; 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 times) daily, weekly, monthly, biannually, annually, or as medically necessary. Dosages may be provided in either a single or multiple dosage regimens. The timing between administrations may decrease as the medical condition improves or increase as the health of the patient declines.
  • Example 1 Preparation of Fc constructs Reverse translations of the amino acids including the protein constructs (SEQ ID NOs: 1, 3, 5, 7, 9, 12, and 14) were synthesized by solid-phase synthesis.
  • the oligonucleotide templates were cloned into pcDNA3.1 (Life Technologies, Carlsbad, CA, USA) at the cloning sites BamHI and XhoI (New England Biolabs, Ipswich, MA, USA) and included signal sequences derived from the human Interleukin-2 or human albumin.
  • the pcDNA3.1 plasmids were transformed into Top10 E. coli cells (LifeTech). DNA was amplified, extracted, and purified using the PURELINK® HiPure Plasmid Filter Maxiprep Kit (LifeTech). The plasmid DNA is delivered, using the EXPIFECTAMINETM 293 Transfection Kit (LifeTech), into HEK- 293 cells per the manufacturer’s protocol.
  • FIGs.5-11 show non-reducing and reducing SDS-PAGE of an Fc domain formed from Fc domain monomers having the sequences of SEQ ID NOs: 1, 3, 5, 7, 9, 12, and 14, respectively.
  • Example 2
  • PEG4-azido Fc 0.050M PEG4-azidoNHS ester PBS buffer solution (1.803 mL, 90.13 mmol, 9.5 equivalents) was added to a solution of h-IgG1 Fc (SEQ ID NO: 4) (552.2 mg in 33.75mL of pH 7.4 PBS, MW ⁇ 58,200 Da, 9.487 mmol) and the mixture was shaken gently for 2 hours at ambient temperature. The solution was concentrated by using six centrifugal concentrators (30,000 MWCO, 15 mL) to a volume of ⁇ 1.5 mL. The crude mixture was diluted 1:10 in PBS pH 7.4, and concentrated again. This wash procedure was repeated for total of three times.
  • the concentrated Fc-PEG4-azide was diluted to 33.75 mL with pH 7.4 PBS 1x buffer and ready for Click conjugation.
  • the purified material was quantified using a NANODROPTM UV visible spectrophotomer (using a calculated extinction coefficient based on the amino acid sequence of h-IgG1 (SEQ ID NO: 4). Yield is quantitative after purification.
  • the nucleic acid construct encoding the Fc for any conjugate described herein may include a nucleic acid sequence encoding the amino acid sequence of an Fc including Lys447 (e.g., a C-terminal lysine residue) and/or an N-terminal murine IgG signal sequence.
  • the C-terminal lysine and, when present, the N-terminal murine IgG signal sequence of the Fc are proteolytically cleaved, resulting in an Fc having the amino acid sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and, when present in the expression construct, the N-terminal murine IgG signal sequence.
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • azido-acetate Fc 0.05M azido-acetate NHS ester PBS buffer solution (4.723 mL, 236.1 mmol, 12.6 equivalents) was added to a solution of h-IgG1 Fc (552.2 mg in 47.92 mL of pH 7.4 PBS, MW ⁇ 53360 Da, 18.74 mmol) then the mixture was shaken rotated for 2 hours at ambient temperature. The solution was concentrated by using six centrifugal concentrators (30,000 MWCO, 15 mL) to a volume of ⁇ 1.5 mL. The crude mixture was diluted 1:10 in PBS pH 7.4, and concentrated again. This wash procedure was repeated for total of three times.
  • the concentrated azido acetate Fc was diluted to 47.92 mL with pH 7.4 PBS buffer. This material was quantified using a NANODROPTM UV visible spectrophotomer using a calculated extinction coefficient based on the amino acid sequence of h-IgG1 (SEQ ID NO: 4). Yield was quantitative after purification.
  • Example 3 The concentrated azido acetate Fc was diluted to 47.92 mL with pH 7.4 PBS buffer. This material was quantified using a NANODROPTM UV visible spectrophotomer using a calculated extinction coefficient based on the amino acid sequence of h-IgG1 (SEQ ID NO: 4). Yield was quantitative after purification.
  • SEQ ID NO: 4 amino acid sequence of h-IgG1
  • the crude mixture was diluted 1:10 in PBS pH 7.4, and concentrated again. This wash procedure was repeated for total of three times. The small molecule reagent was removed with this wash procedure.
  • the concentrated MSA-PEG4-azide was diluted to 75.0 mL with pH 7.4 PBS 1x buffer and ready for Click conjugation.
  • the purified material was quantified using a NANODROPTM UV visible spectrophotomer (using a calculated extinction coefficient based on the amino acid sequence of h-IgG1). Yield is quantitative after purification.
  • DAR 3.5 determined by MALDI. The DAR value can be adjusted by altering the equivalents of PEG4-azido NHS ester similar to h-IgG1 Fc (Example 2).
  • step-b product 104.6 mg, 0.226 mmol
  • DIPEA 65 mg, 0.5 mmol
  • BOP reagent 104.9 mg, 0.238 mmol
  • the resulting mixture was heated at 70°C for 10 minutes, then 3-Boc-aminomethylazetedine (63 mg, 0.27 mmol) was added.
  • the reaction was continued at 70 °C for 1 hour.
  • Example 6 Synthesis of Int-3 The major product from step-b of Example 5 (Int-2) (23.4 mg, 0.0297 mmol) was dissolved in MeOH (2 ml), and the solution was treated with 30% NaOH in water (0.5 ml) and 1ml of water. The resulting mixture was heated at 70 °C for 3 hours.
  • Example 7 Synthesis of Int-4 Step a. To a solution of starting material (231.5 mg, 0.5 mmol, described in Example 4, Int-1) in anhydrous DMF (1 ml) was added DIPEA (129.2 mg, 1 mmol) and BOP reagent (243.3 mg, 0.55 mmol). The resulting mixture was heated at 70 °C for 10 minutes, then (3R,4S)-(4-hydroxy-pyrrolidin-3-yl)- carbamic acid tert-butyl ester (132 mg, 0.65 mmol) was added. The reaction was continued at 70 °C for 1 hour.
  • Step b To a solution of the step-a product (104 mg, 0.162 mmol) in anhydrous DMF (1 ml) was added propargyl-PEG4-bromide (95.6 mg, 0.324 mmol) and potassium carbonate (44.8 mg, 0.324 mmol). The resulting mixture was heated at 100 °C for 5 hours. It was then purified by preparative HPLC (5% to 60% acetonitrile and water, using 0.1% TFA as modifier).
  • Step b To a solution of product from the previous step (0.8 g, 2.0 mmol) in anhydrous DMF was added sodium hydride (200 mg, 60% in oil, 5 mmol) and propargyl bromide (80 wt. % in toluene, 0.45 ml, 4 mmol) under the ice-water bath. The reaction was stirred for 4 hrs at room temperature under nitrogen atmosphere, then the mixture was concentrated and purified by column chromatography over silica silica eluted with 0% to 20% ethyl acetate and methanol. Yield of 0.7 g, 80%.
  • Example 9 Synthesis of Conjugate 4
  • the Click reagent solution 0.0050 M CuSO4 in PBS buffer solution: 10.0 mg CuSO4 was dissolved in 12.53 mL PBS, then took 6.00 mL this CuSO4 solution and added BTTAA (51.7 mg, CAS# 1334179-85-9) and sodium ascorbate (297.2 mg) to give the Click reagent solution (0.0050M CuSO4, 0.020M BTTAA and 0.25M sodium ascorbate). This Click reagent solution was used for all of conjugations.
  • the nucleic acid construct encoding the Fc for any conjugate described herein may include a nucleic acid sequence encoding the amino acid sequence of an Fc including Lys447 (e.g., a C-terminal lysine residue) and/or an N-terminal murine IgG signal sequence (e.g., SEQ ID NO: 35).
  • Lys447 e.g., a C-terminal lysine residue
  • N-terminal murine IgG signal sequence e.g., SEQ ID NO: 35.
  • the C-terminal lysine and, when present, the N-terminal murine IgG signal sequence of the Fc are proteolytically cleaved, resulting in an Fc having the amino acid sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and, when present in the expression construct, the N-terminal murine IgG signal sequence.
  • Example 11 Activity of pre-conjugation intermediates (Ints) and conjugates in an RSV Cytopathic Effects (CPE) assay
  • the activity of anti-RSV compounds and conjugates was determined using an in vitro cell-based assay following a standard protocol in the field. Briefly, ten four-fold serial dilutions of each test article (TA) starting at 10 ⁇ M were prepared in duplicate and incubated with RSV (Respiratory Syncytial Virus strain A 2 ) at a multiplicity of infection (MOI) of 0.01, for one hour. The RSV-TA mix was then added to HEp-2 cells seeded in 96-well plates and incubated for one hour.
  • TA test article
  • MOI multiplicity of infection
  • Example 12 RSV F protein binding assay Nunc MaxiSorp flat-bottom 96-well plates (12-565-136, Fisher Scientific) were coated with recombinant RSV F protein (11049-V08B, Sino Biological) at 1 ⁇ g/mL in Seracare KPL coating solution (50-674-4, Fisher Scientific) at room temp for 1 h (100 ⁇ L, 0.1 ⁇ g/well) on an orbital microplate shaker at 500 rpm (BT908, BT LabSystems). Plates were washed (5 x 300 ⁇ L) with wash buffer (PBS 0.05% Tween 20) and blocked with 5% non-fat dry milk (9999S, Cell Signaling Technology) in wash buffer for 1 h at room temp with shaking.
  • wash buffer PBS 0.05% Tween 20
  • the blocking agent was removed and wells incubated with 3-fold serial dilutions of RVC in sample diluent (2.5% non-fat milk in PBS 0.025% Tween 20) starting at 2 ⁇ M for 2 h with shaking at room temp. After 5 x 300 ⁇ L washes, the plates were incubated with HRP conjugated donkey anti-human IgG Fc F(ab’)2 (709-036-098, Jackson ImmunoResearch) secondary antibody diluted 1:1,000 in sample diluent for 1 h with shaking at room temp. Plates were then washed (8 x 300 ⁇ L) and developed with TMB substrate (BD555214, Fisher Scientific) for 3-5 minutes at room temp.
  • PEG4-azido Fc 0.050M PEG4-azidoNHS ester PBS buffer solution (0.593 mL, 29.6 mmol, 16 equivalents) was added to above solution of h-IgG1 Fc (SEQ ID NO: 48) and the mixture was shaken rotated for 2 hours at ambient temperature. The solution was concentrated by using four centrifugal concentrators (30,000 MWCO, 15 mL) to a volume of ⁇ 1.5 mL. The crude mixture was diluted 1:10 in PBS pH 7.4, and concentrated again. This wash procedure was repeated for total of three times. The concentrated Fc-PEG4-azide was diluted to 8.80 mL with pH 7.4 PBS buffer and ready for Click conjugation.
  • Example 14 Synthesis of Conjugate 6 A solution of azido functionalized Fc (75 mg, 7.5 mL, 1.406 umol, Example 13; SEQ ID NO: 35 functionalized with PEG4-azide) was added to a 40 mL centrifuge tube containing alkyne functionalized small molecule (12.2 mg, 13.49 umol, described in Example 8, Int-5).
  • the nucleic acid construct encoding the Fc for conjugate 6 included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 6 are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • Lys447 e.g., lacking a C-terminal lysine residue
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • the nucleic acid construct encoding the Fc for conjugate 3a included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 3a are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • Lys447 e.g., lacking a C-terminal lysine residue
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • the nucleic acid construct encoding the Fc for conjugate 3b included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 3b are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • Lys447 e.g., lacking a C-terminal lysine residue
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • Step b The intermediate from step a (4 g, 14.4 mmol), tosyl chloride (3.6 g, 18.7 mmol), and triethylamine (2.6g, 25.9 mmol) were stirred in DCM (50 mL) at room temperature for 12 hours. DI water was added and the mixture was extracted with DCM (3 x 30mL). The combined organic extracts were washed with brine and dried over sodium sulfate.
  • Step b Synthesis of tert-butyl 2'-oxo-1',2'-dihydro-1H-spiro[piperidine-4,3'-pyrrolo[2,3- c]pyridine]-1-carboxylate
  • methanol 10 ml
  • palladium on charcoal 0.2 g
  • Palladium was removed by filtration after the reaction was complete as indicated by LCMS.
  • saturated NaHCO 3 solution 5 ml
  • Boc anhydride (0.44 g, 2.1mmol
  • Step d Synthesis of 4-chloro-N-1-(4-fluorobutyl)benzene-1,2-diamine To a solution of the products from previous step (1.3 g, 5.3 mmol) in ethanol (30 ml) was added a saturated ammonium solution (12 ml). The resulting solution was heated to 60°C and Zin powder (3.3g, 5mmol) was added.
  • Step f Synthesis of t-butyl 1- ⁇ [5-chloro-1-(4-fluorobutyl)-1H-benzimidazol-2-yl]methyl ⁇ -2- oxo-1,2-dihydro-1'H-spiro[indole-3,4'-piperidine]-1'-carboxylate
  • sodium hydride 0.2 g, 4 mmol, 60% in oil
  • dry DMF 5 ml
  • Step c HATU (92 mg, 0.24 mmol) was added to a stirring mixture of the intermediate described in step b. of this example (170 mg, 0.19 mmol), propargyl-peg4-carboxylic acid ( 63 mg, 0.24 mmol), and triethylamine (94 mg, 0.93 mmol) in DMF (3 mL).
  • Example 23 Synthesis of Int-24 CBZ-Piperazine (4 g, 18.2 mmol), n-bromo-butanol (4.2 g, 27.2 mmol), and triethylamine (3.7 g, 36.3 mmol) were stirred in DMF (15 mL) at 60°C for 12 hours. Half of the solvent was removed by rotary evaporator. DI water was added and the mixture was extracted with ethyl acetate (3x, 30mL). The combined organic extracts were washed with brine and dried over sodium sulfate. The solvent was removed and the residue was purified by silica gel chromatography (0% to 5% methanol in DCM) to afford the product as a thick clear oil.
  • Step b Oxalyl chloride was added to DCM (15 mL) cooled to -78°C (dry ice /acetone bath) under an atmosphere of nitrogen. DMSO (801 mg, 10.26 mmol in 5 m of DCM was added to the oxalyl chloride solution dropwise via syringe over a period of 5 minutes. The mixture was stirred at -78 °C for 10 minutes at which point the intermediate alcohol described in step a of this example (1.5g, 5.13 mmol, in 5 mL DCM) was added dropwise via syringe over a period of 5 minutes. The mixture was stirred at -78 °C for 30 minutes.
  • Step e The intermediate from step d (282 mg, 0.37 mmol) was dissolved in DMF (2 mL), then treated with propargyl-peg4-bromide (140 mg, 0.47 mmol), and N,N-diisopropylethylamine (188 mg, 1.5 mmol) and stirred at 80°C for 3 hours.
  • the boc-protected intermediate was stirred in TFA (3 mL) at room temperature for 30 minutes. The solvent was removed by the rotary evaporator and purified by reversed phase HPLC chromatography ISCO ACCQ semi prep (20-95% acetonitrile in DI water, 0.1% TFA, 30 minute gradient). The pure fractions were pooled and lyophilized to afford the desired product as an off white solid.
  • Step b To a 0 °C stirring solution of the product from step a (250 mg, 0.432 mmol), 5,5-dimethoxyvaleric acid (77 mg, 0.475 mmol) and DIPEA (226 uL, 1.296 mmol) in DMF (3.0 mL) and DCM (0.5 mL), was added HATU (168 mg, 0.440 mmol). The temperature was raised to ambient and stirring was continued overnight.
  • Step c The product from step b (294 mg, 0.407 mmol) dissolved in acetic acid (3.0 mL) and water (1.5 mL), and stirred until full conversion to the desired aldehyde was observed by analytical HPLC. All the volatiles were evaporated. The aldehyde was used in the next step without further purification. Yield 0.275 g, quant.
  • the nucleic acid construct encoding the Fc for conjugate 7 included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 7 are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • Lys447 e.g., lacking a C-terminal lysine residue
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • Example 26 The presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • the nucleic acid construct encoding the Fc for conjugate 8 included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 8 are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • Step a To a 0 °C stirring solution of Fmoc-N-(tert-butyloxycarbonylmethyl)-glycine (672 mg, 1.636 mmol), propargyl-PEG8-amine (667 mg, 1.636 mmol) and DIPEA (712 uL, 4.090 mmol) in DMF (4.0 mL) and DCM (4.0 mL), was added HATU (634 mg, 1.668 mmol). The temperature was raised to ambient and stirring was continued until complete as determined by LCMS. All the volatiles were removed per rotatory evaporation.
  • Step d The product from step c of this example (300 mg, 0.248 mmol) was dissolved in acetic acid (4.0 mL) and water (2.0 mL), and stirred until full conversion to the desired product was observed by analytical HPLC. All the volatiles were evaporated per rotatory evaporation. This material was used in the next step without further purification. Yield 290 mg, quant. Step e.
  • Example 28 Synthesis of Int-27
  • PEG-presatovir 200 mg, 0.221 mmol, described in Example 8, Int-5) and DIPEA (162 uL, 0.926 mmol) in dichloromethane (3.0 mL)
  • di-tert-butyl dicarbonate 72 mg, 0.331 mmol.
  • Step b To a 0 °C stirring solution of Fmoc-N-(tert-butyloxycarbonylmethyl)-glycine (2.00 g, 4.861 mmol), 2-azidoethylamine hydrochloride (626 mg, 5.104 mmol) and DIPEA (3.387 mL, 19.44 mmol) in DMF (10 mL) and DCM (10 mL), was added HATU (1.885 g, 4.958 mmol). The temperature was raised to ambient and stirring was continued until complete as determined by LCMS.
  • Step d To a 0 °C stirring solution of the product from step c (990 mg, 2.338 mmol), methyl-PEG12-amine (1.335 g, 2.385 mmol) and DIPEA (1.018 mL, 5.845 mmol) in DMF (5.0 mL) and DCM (5.0 mL), was added HATU (907 mg, 2.385 mmol). The temperature was raised to ambient and stirring was continued until complete by HPLC. All the volatiles were removed per rotatory evaporation. The residue was purified by silica column using an Isco COMBIFLASH® liquid chromatography eluted with 0% to 15% methanol in dichloromethane. Yield 1.704 g, 76% yield.
  • the nucleic acid construct encoding the Fc for conjugate 9 included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 35, which includes a C-terminal lysine residue and N-terminal murine IgG signal sequence.
  • the C-terminal lysine and the N-terminal murine IgG signal sequence of the Fc of conjugate 9 are proteolytically cleaved, resulting in an Fc having the sequence lacking Lys447 (e.g., lacking a C-terminal lysine residue) and the N-terminal murine IgG signal sequence.
  • Lys447 e.g., lacking a C-terminal lysine residue
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • Example 30 Synthesis of Int-28 The title compound was prepared analogously to Example 8, Int-5, where the hexaethylene glycol was substituted with PEG12 glycol in step a of the sequence.
  • Example 32 Synthesis of Int-30 A solution of tert-butyl 3-amino-3-carbamoylazetidinecarboxylate ( 1.56 g, 5.99 mmol) in CH 2 Cl2 (46 mL) at 0 °C under nitrogen gas was added triethylamine (2.53 mL, 17.98 mmol) and N-(benzyloxycarbonyloxy)succinimide (1.83 g, 7.19 mmol). The resulting solution was allowed to warm to room temperature overnight. The reaction mixture was washed with water, dried over Na2SO4, filtered, and then concentrated. The residue was purified by normal phase liquid chromatography (Isco, 10 to 100% ethyl acetate and hexane).
  • Step b A solution of primary amide from a previous step (1.4 g, 4.01 mmol) in anhydrous THF (8.5 mL) at 0 °C under nitrogen was treated with BH3-THF (12.02 mL, 12.02 mmol) dropwise. The reaction mixture was stirred at 0 °C for 1 hour then an ice bath was removed. It was stirred for an additional 30 minutes before slowly quenching with methanol. The resulting solution was concentrated under reduced pressure.
  • Step c To a solution product from the previous step (0.61 g, 1.36 mmol) in anhydrous THF (5 mL) under nitrogen was added triethylamine (0.59 mL, 4.21 mmol). The reaction mixture was cooled down to 10 °C then 2,4-dichloro-6-methylquinazoline (0.28 g, 1.31 mmol) was added slowly to keep the internal temperature below 30 °C .
  • Step f A solution of amine product from a previous step (0.15 g, 0.22 mmol), propagyl-PEG-4-tosylate (0.097g, 0.25 mmol), NaI (3.27 mg, 0.022 mmol) and K 2 CO 3 (0.091 g, 0.66 mmol) in anhydrous acetonitrile (4 mL) was heated at 80 °C for 16 hours. The reaction mixture was filtered and concentrated, then purified by reverse phase liquid chromatography (Isco, 5 to 45% acetonitrile and water, using 0.1%TFA as modifier).
  • Example 33 Synthesis of Int-31
  • Example 34
  • the nucleic acid construct encoding the Fc for Conjugate 10 included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 64, which includes a C-terminal lysine residue.
  • the C-terminal lysine of the Fc of Conjugate 10 is proteolytically cleaved, resulting in an Fc having the sequence of SEQ ID NO: 73.
  • the presence or absence of a C-terminal lysine does not alter the properties of the Fc or the corresponding conjugate.
  • Microneutralization assay for quantifying RSV neutralizing compounds HEp-2 cells were seeded at 5E4/well/200 ⁇ L in DMEM (Fisher cat # 11965118) supplemented with 10% heat-inactivated (HI) fetal bovine serum (HI-FBS; Fisher cat # 10-082-147), 1X penicillin-streptomycin (P/S, 100 ⁇ g/mL; Fisher cat # MT30002C), and 1X L-glutamine (L-Gln, 2 mM; Fisher cat # 25030-164) in 96-well tissue culture treated plates (Fisher cat # 08-772-17) and incubated overnight at 37 ⁇ C and 5% CO2.
  • Duplicate 10-fold serial dilutions of compound in DMEM with 2% HI-FBS, 1X P/S, 2 mM L-Gln were prepared in 96-well tissue culture plates at 60 ⁇ L/well.
  • the RSV Long strain (RetroVirox, San Diego), RSV A 2 strain (Virapur, San Diego), RSV B1 strain (RetroVirox, San Diego), or RSV strain CH18537 (RetroVirox, San Diego) were diluted in DMEM with 2% HI-FBS, 1X P/S, 2 mM L- Gln and 60 ⁇ L/well added to 60 ⁇ L compound for a multiplicity of infection (MOI) of 0.002 (Long, A 2 ), 0.003 (B1), or 0.004 (CH18537).
  • MOI multiplicity of infection
  • Virus only (no drug) and cells only (no virus, no drug) controls were included on each plate.
  • the compound-virus mix was incubated for 1 h at 37 ⁇ C and 5% CO 2 . After 1 h, medium was removed from HEp-2cells by aspiration and wells washed once with 100 ⁇ L/well 1X PBS pH 7.4 (Fisher cat # MT21040CM).
  • the compound-virus mix (100 ⁇ L/well) was added to the cells and incubated for 1 h at 37 ⁇ C and 5% CO2 prior to addition of 100 ⁇ L/well of DMEM with 2% HI-FBS, 1X P/S, 2 mM L-Gln (200 ⁇ L final vol) and incubation at 37 ⁇ C and 5% CO2.
  • supernatant was aspirated and cells fixed with 100 ⁇ L/well ice-cold 80% acetone in 1X PBS for 20 min at 4 ⁇ C. The acetone was aspirated and plates air-dried for 20 min at room temperature.
  • the plates were washed 3x with 200 ⁇ L/well 1X PBS, 0.05% Tween-20 (PBST) and blocked with 200 ⁇ L/well 5% non-fat dry milk (Fisher cat # 50-195-952) in PBST for 1 h with shaking (500 rpm) on an orbital plate shaker.
  • the blocking solution was discarded and cells incubated with 100 ⁇ L/well mouse anti-F protein antibody (MilliporeSigma cat # MAB8599) diluted 1:2,000 in diluent (blocking solution diluted 1:1 in 1X PBS pH 7.4) for 2 h with shaking.
  • Plates were washed 5x with 300 ⁇ L/well PBST and incubated with 100 ⁇ L/well HRP- conjugated goat anti-mouse IgG antibody (SouthernBiotech cat # 1030-05) diluted 1:1,000 in diluent for 1 h with shaking. Plates were washed 5x with 300 ⁇ L/well PBST and incubated with 100 ⁇ L/well TMB substrate (Fisher cat # BDB555214) for ⁇ 5 min. The reaction was stopped with 100 ⁇ L/well 1N H2SO4. Absorbance was read at 450 nm with an EnSpire multimode plate reader (PerkinElmer).
  • the mean A450 for the cells only control was subtracted from all A450 values, and the percent virus neutralisation calculated for each compound concentration, relative to the virus only control.
  • Half maximal effective concentration (EC50) was calculated with GraphPad Prism version 8 using nonlinear regression analysis of % neutralisation vs. log10 concentration plots.
  • the 50% cytotoxic concentration (CC50) at day 6 post infection was determined for assays run in parallel with the microneutralization assay. Briefly, the medium was removed by aspiration and the cells fixed/ stained for 1 h at room temperature with 60 ⁇ L/well crystal violet solution (0.1% crystal violet, 20% methanol, 3% paraformaldehyde). The stain was removed and wells washed 3x times with 100 ⁇ L/well 1X PBS pH 7.4.
  • Example 38 Synthesis of a conjugate including an Fc domain having a C220S/YTE quadruple mutation
  • Preparation of the Click reagent solution 0.0050M CuSO4 in PBS buffer solution: 10.0 mg CuSO4 was dissolved in 12.53 mL PBS, then took 5.00 mL this CuSO4 solution and added 43.1 mg BTTAA (CAS# 1334179-85-9) and 247.5 mg sodium ascorbate to give the Click reagent solution (0.0050M CuSO4, 0.020M BTTAA and 0.25M sodium ascorbate).
  • a conjugate including an Fc domain monomer having a C220S/YTE quadruple mutation may alternately be prepared using an Fc domain having the amino acid sequence of SEQ ID NO: 77, corresponding to a difference in Fc allotype.
  • the differing allotypes are expected to behave the same with respect the properties described herein.
  • the nucleic acid construct encoding the Fc having the CYTE mutation included a nucleic acid encoding the amino acid sequence of SEQ ID NO: 67, which includes a C-terminal lysine residue.
  • Example 39 30-day comparative non-human primate PK study following IV administration of a conjugate including an Fc domain having a C220S/YTE quadruple mutation
  • a conjugate including an Fc domain having a C220S mutation and a YTE mutation was synthesized as described in Example 38.
  • a non-human primate PK study was performed to compare IV administration of the C220S/YTE Fc conjugate (SEQ ID NO: 76) to a conjugate including an Fc domain having a C220S mutation alone (SEQ ID NO: 73).
  • Non-human primate (NHP) PK studies were performed by BTS Research (San Diego, CA) using male and female cynomolgus monkeys 5-9 years old with body weights ranging from 3.5-8.5 kg. NHPs were injected IV with 2 mg/kg of test article (0.4 mL/kg dose volume). Animals were housed under standard IACUC approved housing conditions.
  • mice were non-terminally bled (via femoral or cephalic veins) with blood collected in K 2 EDTA tubes to prevent coagulation. Collected blood was centrifuged (2,000 x g, for 10 minutes) and plasma withdrawn for analysis of test article concentrations over time. The plasma concentrations for the C220S/YTE Fc conjugate and the C220S conjugate at each time point were measured by sandwich ELISA. Briefly, test articles were captured on Fc-coated plates and then detected using a HRP-conjugated anti-human IgG-Fc antibody. Protein concentrations were calculated in GraphPad Prism using 4PL non-linear regression of the C220S/YTE Fc conjugate or C220S conjugate standard curves.
  • the C220S/YTE Fc conjugate demonstrates a significantly improved terminal half-life of ⁇ 45 days compared with ⁇ 10 days for the C220S Fc conjugate.
  • AUCs for the C220S/YTE Fc conjugate are 2X greater than the AUCs for The C220S conjugate (Table 7).
  • Example 40.14-day mouse PK study comparing plasma and epithelial lining fluid (ELF) concentrations of a conjugate including an Fc domain Female BALB/c mice from Charles River Laboratories were allowed to acclimate for 5 days prior to study commencement. Animals were housed 3-6 per cage with free access to food and water. All procedures were performed to NeoSome IACUC policies and guidelines. Mice were injected subcutaneously (SC) with 20 mg/kg of a conjugate having an Fc domain (SEQ ID NO: 73) decorated with one or more small molecule antiviral inhibitors (10 mL/kg dose volume). At selected time points, 3 mice were euthanized by CO2 inhalation.
  • SC subcutaneously
  • SEQ ID NO: 73 Fc domain
  • small molecule antiviral inhibitors 10 mL/kg dose volume
  • a bronchoalveolar lavage was performed by exposing the trachea, inserting a 23G tubing adaptor, and performing 2 x 0.5 mL flushes with sterile 1X PBS pH 7.4. The recovered fluid volume was recorded and retained. Once the BAL procedure was complete, the lungs were removed, weighed and stored at -80 ⁇ C. Aliquots of the plasma and BAL fluid (BALF) were decanted prior to -80 ⁇ C storage of the samples for use in a urea quantification assay.
  • BAL bronchoalveolar lavage
  • the collected BALF was centrifuged at 12,000 RPM for 5 minutes at room temperature to pellet the alveolar macrophages with both the pellet and supernatant stored at -80 ⁇ C until shipment to sponsor.
  • the plasma concentrations for the conjugate at each time point were measured by indirect ELISA as described above. Briefly, the conjugate molecules were captured on neuraminidase (NA) coated plates and then detected using a HRP-conjugated anti-human IgG Fcg specific F(ab')2. The same ELISA was performed on BALF harvested as described above. The conjugate plasma concentrations were calculated in GraphPad Prism using 4PL non-linear regression of the conjugate standard curves.
  • ELF volume and conjugate concentration in ELF was determined using urea as a dilution marker as described previously (Rennard et al., 1986 J Appl Physiol 60:532-538).
  • the curves comparing conjugate to ELF levels are shown in FIG. 14.
  • conjugate epithelial lining fluid (ELF) levels are ⁇ 60% of plasma exposure levels (AUCs) across the rest of the time course indicating nearly immediate partitioning of conjugate 45 from plasma to the ELF in the lung (FIG.14, Table 8).
  • Example 41 Synthesis of 5-chloro-2-(chloromethyl)-1-[3-(methanesulfonyl)propyl]-1H- benzimidazole
  • Step a A solution of 5-Chloro-2-fluoronitrobenzene (0.918g, 5.23 mmol), in DMF (10mL) was treated with 3- Methanesulfonyl-propyl-ammonium chloride (1.000g, 5.757 mmol), and powdered potassium carbonate (2.17g 15.70 mmol), then heated in a 70 °C oil bath. After 12h LCMS shows complete conversion.
  • Step b Crude product from the previous step was dissolved in acetic acid (10mL), heated with a 70 °C oil bath, and treated with zinc powder (1.711g, 26.17 mmol) in several portions, while rapidly stirring. After 10 minutes the orange color becomes colorless, and LCMS indicated that reaction was complete. The reaction mixture was filtered, giving a green colored solution, which was used immediately in the next step without further purification. Step c.
  • Example 47 Synthesis of 5-chloro-2-(chloromethyl)-1-(4,7,10,13,16-pentaoxaicos-1-yn-20-yl)-1H- benzimidazole
  • Step b To a stirring solution of product from the previous step a (1.100 g, 3.00 mmol) and phthalimide (0.881 g, 6.00 mmol) in DMF (7mL), was added powdered potassium carbonate (1.66 g, 11.98 mmol). The mixture was stirred in a 70 °C oil bath for 1h, at which time LCMS showed complete disappearance of starting bromide.
  • Step c A solution of product from the previous step b (1.10 g, 2.54 mmol) dissolved in ethanol (3 mL), was treated with 40% aqueous methyl amine (3 mL) and heated in 70 °C oil bath for 1h, at which time LCMS show complete consumption of starting material. The reaction was concentrated by rotary evaporation, then stored under high vacuum overnight, and used as mixture of N-methyl-phthalimide and desired product in the next step without further purification. Step d.
  • Step b A solution product from the previous step a (3.71g, 7.33 mmol), and 5% Pd/C (1.5g) was dissolved in methanol (30 mL), and vacuum flushed with hydrogen gas and stirred with hydrogen from a balloon for 1hr. The reaction was filtered through celite. The filtrate was concentrated by rotary evaporation, and then used in the next step without further purification.
  • Step c Product from the previous step b (2.73 g, 7.33 mmol), and propargyl-PEG4-mesylate (2.50 g, 8.06 mmol), were dissolved in acetonitrile (20 mL), then treated with DIEA (3.831 mL, 22.0 mmol), and heated in a 75 °C oil bath for 24h. The crude reaction was concentrated by rotary evaporation, made slightly acid with TFA, and purified by RPLC (10-100% ACN/water with 0.1% TFA). Yield 3.24 g, 63.1 %.
  • Step b Product from the previous step a (0.911g, 1.39 mmol) was dissolved in 4M HCL in dioxane and stirred for 1 hr. The reaction was concentrated by rotary evaporation, and stored under high vacuum overnight. Crude yield of 9 HCl salt was 0.92g, 98%.
  • Example 53 Synthesis of Int-39 To a solution of tetraethylene glycol (3.8 g, 20 mmol) in dry DMF was slowly added sodium hydride (0.48 g, 12 mmol, 60 % in mineral oil). The solution was stirred on ice bath for 10 mins, and then 2-(4-bromobutyl)isoindoline-1,3-dione (2.8 g, 10 mmol) was added. The reaction solution was stirred at room temperature for 16 hours, quenched with tert-butanol (1 ml) and concentrated.
  • step e A mixture of the product from step d, 5-chloro-2-fluoronitrobenzene (210 mg, 1.2 mmol), and K 2 CO 3 (496 mg, 3.6 mmol) in dry acetonitrile was heated at 70 °C for 2 hours.
  • the Boc protected intermediate was stirred in 4N HCl in dioxane (25 mL) at ambient temperature for 30 minutes. The solvent was removed on the rotary evaporator, azeotroped with toluene (3x, 10 mL), and dried under high vacuum to afford the product as a yellow oil. Yield 69%, 3 steps.
  • LC/MS [M+H] + 338.2.
  • Example 56 Synthesis of Int-36
  • the product of Example 49 (66 mg, 0.23 mmol), the intermediate from step c. of Example 55 (Synthesis of Int-43) (120 mg, 0.23 mmol), and cesium carbonate (75 mg, 0.23 mmol) were stirred together in DMF (2 mL) at ambient temperature for 12 hours.
  • Step c To crude 1-[(5-chloro-1- ⁇ 3-[(2- ⁇ 2-[2-(2-prop-2-ynyloxyethoxy)ethoxy]ethoxy ⁇ ethyl) sulfonyl]propyl ⁇ benzimidazol-2-yl)methyl]spiro[2-pyrrolino[2,3-c]pyridine-3,4'-piperidine]-2-one (25 mg, 0.040 mmol assuming 100% yield) in DMF (5 mL) was added Boc-Thr-OH (10 mg, 0.05 mmol) followed by Hünigs base (2 drops).
  • Example 61 Synthesis of Int-37 4N HCl in Dioxane (6 mL) was added to N-(1-((1R)-1-hydroxyethyl)(1S)-2- ⁇ 1-[(5-chloro-1- ⁇ 3-[(2- ⁇ 2-[2-(2-prop-2-ynyloxyethoxy)ethoxy]ethoxy ⁇ ethyl)sulfonyl]propyl ⁇ benzimidazol-2-yl)methyl]-2-oxospiro[2- pyrrolino[2,3-c]pyridine-3,4'-piperidine]-10-yl ⁇ -2-oxoethyl)(tert-butoxy)carboxamide (15 mg, 0.020 mmol, described in Example 59, Int-43) and the solution was stirred for 1h.
  • Example 62 Synthesis of Int-38 The title compound was prepared analogously to Example 61 (Int-37) from crude (tert-butoxy)-N-(2- ⁇ 1-[(5- chloro-1- ⁇ 3-[(2- ⁇ 2-[2-(2-prop-2-ynyloxyethoxy)ethoxy]ethoxy ⁇ ethyl) sulfonyl]propyl ⁇ benzimidazol-2- yl)methyl]-2-oxospiro[2-pyrrolino[2,3-c]pyridine-3,4'-piperidine]-10-yl ⁇ -2-oxoethyl)carboxamide (described in Example 60, Int-45).
  • Step b The product from step-a (1.4 g, 4.01 mmol) in anhydrous THF (8.5 mL) at 0 °C under Nitrogen was treated with BH3-THF (1M, 12 mL, 12.02 mmol). The reaction mixture was stirred at 0 °C for 1 hour then the ice bath was removed and stirred for another 30 minutes. It was quenched with methanol before the reaction completed.
  • Step c To a solution of the product from step-b (608.34 mg, 1.35 mmol) in anhydrous THF (5 mL) under nitrogen was added triethylamine (0.59 mL, 4.21 mmol). The resulting solution was cooled down to 10 °C then 6-methyl-2,4-dichloroquinazoline (280 mg, 1.31 mmol) was added slowly to keep the reaction temperature below 30 C.
  • Example 66 Synthesis of Int-31
  • the product from step-c of Example 65 (Int-30) (217.4 mg, 0.27 mmol), propagyl-PEG8-bromide (140.6 mg, .029 mmol), potassium carbonate (91.8 mg, 0.66 mmol) and NaI (3.98 mg, 0.027 mmol) in acetonitrile (4 mL) was heated 80 °C for 16 hours.
  • the reaction mixture was filtered then purified by RPLC (ACCQ, 0% to 40% acetonitrile and water, using 0.1%TFA as modifier). Yield 147.0 mg, 51.4%.
  • Step b The product from the previous step (370.4 mg, 1.82 mmol) was dissolved in DCM (5 mL) at 0 °C was added 2-chloro-1,1,1-trimethoxyethane (1.75 mL, 12.7 mmol) and concentrated aqueous HCl (0.23 mL, 2.73 mmol).
  • Step b To a solution of product from the previous step (0.52 g, 2.09 mmol) in MeOH:ethyl acetate:THF (1:1:1, 42 mL) at room temperature was charged with Raney Nickel as suspension in isopropanol (2.0 g, 34.08 mmol, previously rinsed with isopropanol) and hydrogen gas balloon. The resulting mixture was stirred for 16 hours then filtered through a pad of celite.
  • Step c The product from the previous step (534.4 mg, 2.44 mmol) was dissolved in DCM (12 mL) at 0 °C was added 2-chloro-1,1,1-trimethoxyethane (2.0 mL, 14.6 mmol) and concentrated aqueous HCl (0.3 mL, 3.66 mmol). The ice bath was removed and the reaction mixture was stirred at 0 °C until completion. The reaction mixture was poured into saturated NaHCO 3 aqueous then extracted with DCM.
  • Example 69 Synthesis of Int-48 Step a.
  • Step b The step-a product (1.1 g, 1.852 mmol) in DCM (7 ml) was treated with TFA (3 ml). The solution was stirred at room temperature for 6 hours. It was then concentrated and purified by RPLC (100 g, 5 to 100% acetonitrile and water). Yield 961 mg as TFA salt, 96.4%.
  • LCMS: [M + H] + 425.0. Step c.
  • Step d To a solution of the step-c product (271.7 mg, 0.253 mmol) in DCM (2 ml) was added TFA (0.5 ml), thioanisole (0.2 ml) and bromotrimethylsilane (0.2 ml). The reaction mixture was stirred at room temperature for 3 hours. It was then concentrated by rotary evaporation and purified by RPLC (100 g, 5 to 60% acetonitrile and water). Yield 152.8 mg, 84.6%.
  • Example 71 Synthesis of Int-50 To a solution of starting material (prepared as described in WO 201406411, 30 mg, 0.0627 mmol) and the product of Example 50 (1-[4-(prop-2-yn-1-yl)piperazin-1-yl]-3,6,9,12-tetraoxapentadecan-15-oic acid , 60 mg, 0.135 mmol) in anhydrous DMF (0.5 ml) was added DIPEA (65 mg, 0.5 mmol) and HATU (38 mg, 01 mmol).
  • step-a product (4.8 g, 13.5 mmol) in anhydrous DMF (15 ml) was added Cs2CO 3 (11 g, 33.75 mmol). The resulting mixture was stirred at room temperature for 30 minutes, then treated with the step-b product in benzene (15 ml). After the reaction was stirred for 2 hours, it was extracted with water (100 ml) and Ethyl acetate (100 ml x 3). The combined organic layers were dried over Na2SO4 and concentrated by rotary evaporation. The residue was purified by silica gel column chromatography (220g, 10 to 50% ethyl acetate in DCM). Yield 4.2 g, 70.2%.
  • Step d A flame-dried reaction flask was purged with nitrogen and charged with the step-c product (3.15 g, 7.41 mmol), sodium tert-butoxide (1.07 g, 11.1 mmol), Pd(II) acetate (499.1 mg, 2.223 mmol), tricyclohexyl phosphine (626.1 mg, 2.223 mmol) and dioxane (14 ml). The resulting mixture was heated at 100 °C under nitrogen for 2 hours. After cooling to room temperature, it was diluted with saturated solution of ammonium chloride (70 ml) and extracted with DCM (100 ml x 4).
  • Step f To a solution of propargyl-PEG4 acid (286.3 mg, 1.1 mmol) in anhydrous DMF (1.5 ml) was added HATU (456 mg, 1.2 mmol) and DIEA (426.7 mg, 3.3 mmol). After stirring for 5 minutes, the reaction mixture was added to a solution of the step-e product (397.9 mg, 1 mmol) in DMF (1 ml). The resulting mixture was stirred for 30 minutes, then directly purified by RPLC (5 to 70% acetonitrile and water, using 0.1% TFA as modifier).
  • Step g A solution of the step-f product (361.3 mg, 0.53 mmol) in acetonitrile (3 ml) was cooled in an ice- water bath and added with a pre-cooled solution of ceric ammonium nitrate(CAN) (350.9 mg, 0.64 mmol) in water (1 ml) and additional water (0.5 ml x 3), which is used to rinsed the CAN glassware. The resulting mixture was stirred at room temperature for 2 hours. It was cooled back in an ice-water bath and mixed with additional CAN (116.2 mg, 0.212 mmol). The reaction was continued at room temperature for two more hours.
  • Example 74 Synthesis of Conjugate 21
  • the title compound was prepared analogously to Example 73 (Conjugate 20), where the alkyne functionalized small molecule described in Example 72 (Int-51) was replaced with the alkyne functionalized small molecule described in Example 71 (Int-50).
  • Example 75 Example 75.
  • Example 78 Synthesis of Int-54 The title compound was prepared analogously to Example 76 (Int-53) from tert-butyl 2- oxospiro[2-pyrrolino[2,3-c]pyridine-3,4'-piperidine]-10-carboxylate and 2-[5-chloro-2- (chloromethyl)benzimidazolyl]-1-(methylsulfonyl)ethane (prepared as described in In
  • a flame-dried reaction flask was purged with nitrogen then charged with the step-a product (7.1 g, 14.9 mmol), sodium tert-butoxide (2.86 g, 29.8 mmol), Pd(II) acetate (669 mg, 2.98 mmol), tricyclohexyl phosphine (835.6 mg, 2.98 mmol) and dioxane (75 ml).
  • the resulting mixture was heated at 100 °C under nitrogen for 4 hours. After cooling to room temperature, it was extracted with water (50 ml) and 2:1 ethyl acetate/hexane (150 ml). The aqueous layer was back extracted with DCM (100 ml x 3).
  • Step c A solution of the step-b product (1.85 mg, 4.68 mmol) in acetonitrile (15 ml) was cooled in an ice- water bath and added with a pre-cooled solution of ammonium Cerium(IV) nitrate (5.14 g, 9.37 mmol) in water (10 ml). The resulting mixture was stirred at 0 °C to room temperature for 2.5 hours.
  • Step d To a solution of the step-c product (138.2 mg, 0.5 mmol) in anhydrous acetonitrile (2 ml) was added Cs2CO 3 (325.8 mg, 1.0 mmol) and the product from Example 48 (241 mg, 0.75 mmol). The resulting mixture was heated at 80°C for 1.5 hours. Additional amount of Example 48 product(112 mg, 0.59 mmol) was added, and the reaction was continued for 2 more hours. It was then cooled to room temperature and purified by HPLC (5 to 80% acetonitrile and water, using 0.1% TFA as modifier). Yield 160 mg, 47.5%.
  • Example 84 Synthesis of Int-60
  • the title compound was prepared step-g product from Example 72 (Int-51) (19 mg, 0.0358 mmol) was dissolved in anhydrous acetonitrile (1 ml). Cs2CO 3 (23.3 mg, 0.0716 mmol) and the product from Example 43 (26 mg, 0.1 mmol) was then added. The resulting mixture was heated at 80 °C for 3.5 hours. It was then cooled to room temperature and purified by HPLC (5 to 70% acetonitrile and water). Yield 16.2 mg, 56.4%.
  • Example 85 Synthesis of Int-61 To a solution of the step-c product from Example 80 (Int-56) (82.5 mg, 0.3 mmol) in anhydrous acetonitrile (1 ml) was added Cs2CO 3 (195.5 mg, 0.6 mmol) and the product from Example 47 (175.5 mg, 0.36 mmol). The resulting mixture was heated at 80 °C for 1.5 hours. Additional amount of the product from Example 47 (175.5 mg, 0.36 mmol) was added, and the reaction was continued for 2 more hours.
  • Example 93 Synthesis of Conjugate 24 Prepared according to the general conjugation procedure using alkyne derivatized small molecule described in Example 89 (Int-63) with Fc (SEQ ID NO: 72) Azido DAR 4.5. Yield 20.5 mg, 41%.
  • MALDI- TOF 62,706.
  • Example 95 Synthesis of Conjugate 24 Prepared according to the general conjugation procedure using alkyne derivatized small molecule described in Example 89 (Int-63) with Fc (SEQ ID NO: 72) Azido DAR 4.5. Yield 20.5 mg, 41%.
  • MALDI- TOF 62,706.

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Abstract

Des compositions et des méthodes pour le traitement d'infections virales comprennent des conjugués contenant des inhibiteurs de la protéine F du virus VRS (par exemple, Presatovir, MDT 637, JNJ 179, TMC353121, Zirésovir ou un analogue de ceux-ci) liés à un monomère Fc, un domaine Fc et un peptide de liaison à Fc, une protéine d'albumine, ou un peptide de liaison à l'albumine. En particulier, les conjugués peuvent être utilisés dans le traitement d'infections virales (par exemple, des infections par le VRS).
PCT/US2020/050022 2019-09-09 2020-09-09 Compositions et méthodes pour le traitement du virus respiratoire syncytial Ceased WO2021050612A1 (fr)

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EP20863252.1A EP4028392A1 (fr) 2019-09-09 2020-09-09 Compositions et méthodes pour le traitement du virus respiratoire syncytial
JP2022515651A JP2022547538A (ja) 2019-09-09 2020-09-09 呼吸器合胞体ウイルス感染症の処置のための組成物及び方法
CN202080077245.8A CN114728937A (zh) 2019-09-09 2020-09-09 用于治疗呼吸道合胞病毒的组合物及方法
CA3153626A CA3153626A1 (fr) 2019-09-09 2020-09-09 Compositions et methodes pour le traitement du virus respiratoire syncytial
AU2020345850A AU2020345850A1 (en) 2019-09-09 2020-09-09 Compositions and methods for the treatment of respiratory syncytial virus
MX2022002842A MX2022002842A (es) 2019-09-09 2020-09-09 Composiciones y metodos para el tratamiento del virus sincitial respiratorio.
PCT/US2021/045074 WO2022032175A1 (fr) 2020-08-06 2021-08-06 Procédés de synthèse de conjugués protéine-médicament
US18/019,944 US20230364251A1 (en) 2020-08-06 2021-08-06 Methods for the synthesis of protein-drug conjugates
TW110129179A TW202220698A (zh) 2020-08-06 2021-08-06 蛋白質－藥物結合物之合成方法
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WO2025085675A1 (fr) * 2023-10-17 2025-04-24 Mary Lynn Niedrauer Conjugués, compositions et méthodes de traitement d'une infection par le vrs

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