WO2025195495A1 - Radionuclide drug conjugate, and preparation method therefor and use thereof - Google Patents

Abstract

The present invention relates to a conjugate having a structure of formula (I) and the use thereof in the preparation of a radionuclide drug conjugate.

Description

A radionuclide conjugate and its preparation method and use Technical Field

The present invention relates to the field of biomedicine, and in particular to a radionuclide conjugate and a preparation method and application thereof.

Background Art

Globally, malignant tumors are one of the major malignant diseases that seriously threaten human health, and their incidence continues to rise. Nuclear medicine, due to its potential and advantages in integrated diagnosis and treatment, is playing an increasingly significant role in cancer diagnosis and treatment. Based on their function, nuclear medicines can be divided into diagnostic and therapeutic nuclear medicines. The former primarily includes single-photon (γ-ray) drugs and positron (β ^- ray) drugs, used in single-photon emission computed tomography (SPECT/CT) and positron emission tomography (PET/CT), respectively. They enable molecular-level investigation of the function and metabolism of nuclear medicines in the human body, enabling rapid, real-time imaging. Therapeutic nuclear medicines are drugs that deliver therapeutic effects through the release of radioactive energy (primarily α-rays, β ^- rays, and Auger electrons) from the decay of radionuclides. Among these, radionuclide drug conjugates (RDCs) combine precise targeting with real-time, sensitive imaging or potent killing, bringing significant clinical benefits to patients and enabling more precise and effective treatment. They are a form of nuclear medicine that has recently garnered widespread attention.

Nuclide-conjugated drugs typically consist of four components: a targeting ligand, a linker, a nuclide, and a chelator. As a class of precision targeted drugs, the core of nuclide-conjugated drugs is the targeting carrier (i.e., the targeting ligand). The advantages of small molecules and peptides as targeting carriers primarily include small molecular weight, strong tissue and tumor penetration, rapid tumor accumulation, low immunogenicity, rapid blood clearance, low hematotoxicity, and simple synthesis. Therefore, current research and development of nuclide-conjugated drugs focuses on small molecules and peptides as targeting carriers. However, the use of small molecules and peptides as targeting carriers also faces several challenges, such as: 1) rapid blood clearance, resulting in excretion before sufficient tumor accumulation; 2) short tumor retention time, resulting in a short-lasting therapeutic effect; 3) obtaining high-affinity small molecules or peptides for any given target is difficult, and high-affinity molecules screened in vitro often exhibit poor drugability in in vivo testing; and 4) most peptide-based RDCs are excreted via the kidney-bladder pathway, resulting in relatively high renal uptake and retention time, posing a risk of nephrotoxicity.

Monoclonal antibodies have also received extensive attention and research in the field of radionuclide-conjugated drugs due to their easy availability, high tumor specificity, long intratumoral retention time, and high absolute uptake. It was approved for marketing as early as 2002 for the treatment of relapsed and refractory non-Hodgkin's lymphoma (NHL). However, due to the large molecular weight of monoclonal antibodies (typically 150 kDa), they penetrate tissues and tumors slowly. Most of the mAbs that enter the body are retained in reticuloendothelial cells and hepatocytes, with only a small amount able to bind to the target protein. Furthermore, due to their long blood circulation half-life (typically exceeding one week), mAbs are exposed to the bloodstream and normal tissues for a prolonged period, resulting in increased hematologic and off-target toxicity. These issues are major factors limiting the clinical application of monoclonal antibody-based RDCs. Monoclonal antibodies can be engineered into a variety of smaller antibody fragments, including antigen-binding fragments (Fab), single-chain variable fragments (scFv), nanobodies (Nb), single-domain antibodies (sdAb), and protein scaffolds. Due to their diverse structures, molecular sizes intermediate between mAbs and small molecules and peptides, and unique pharmacokinetic properties, antibody fragments have also been widely used in the development of targeted nuclear medicines, particularly for in vivo imaging and disease diagnosis. However, due to their rapid clearance from the blood circulation, limited accumulation in tumors, and relatively short retention time in tumors, they are difficult to achieve effective therapeutic effects in tumor treatment. Although various strategies have been developed to address these issues with small antibody fragments, such as the introduction of PEG, peptides, Fc fragments, albumin, or Fc and albumin binding fragments, these strategies all have certain limitations and cannot be used as a universal means to solve various problems.

There is an urgent need in the art for new radionuclide drug conjugates (RDCs) that can solve the above problems.

Summary of the Invention

In one aspect, the present invention provides a radionuclide conjugate comprising the following structure:

in,

is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling;

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

_La is connected to the targeting moiety and the coupling unit of G, each _La is independently selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, C _2-6 alkynyl, C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20;

o is an integer or non-integer greater than 0 and less than 20.

In a second aspect, the present invention provides a radionuclide conjugate comprising the following structure:

in,

is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling;

Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each _La is independently selected from the following 1), 2) or a combination thereof:

1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, C _2-6 alkynyl, C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Preferably,

^G1 and ^G3 are independently selected from a chemical bond or the following structures:

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

Preferably, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,

The end of the wavy line with * is close to one end;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, k2 are each independently an integer from 0 to 10;

o is an integer greater than 0 and less than 10 or a non-integer.

In a third aspect, the present invention provides a compound comprising the following structure:

in,

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

L _a' is selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20.

In a fourth aspect, the present invention provides a compound comprising the following structure:

in,

Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each L _a' is independently selected from the following 1), 2) or a combination thereof:

1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, and k2 are each independently an integer of 0-10.

In a fifth aspect, the present invention provides a compound comprising the following structure:

in,

Q is the albumin binding unit;

D and D' are each independently a chelating group for a radionuclide;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

L ₁ , L ₂ , each of L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and C _1-10 alkyl;

m is an integer selected from 0-20;

n is an integer selected from 2-20.

In a sixth aspect, the present invention provides a radionuclide conjugate comprising the following structure:

in,

Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, wherein G is selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkyl group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20.

In a seventh aspect, the present invention provides a radionuclide-conjugated drug comprising the following structure:

in,

Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, and k2 are each independently an integer of 0-10.

In an eighth aspect, the present invention provides a radionuclide conjugate comprising a compound fragment of the following formula (III'):

in,

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

L ₁ , L ₂ , each L _1′ and L _2′ are each independently covalently linked to a chelating group or an albumin binding unit; wherein L ₁ , L ₂ , each L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl;

m is an integer selected from 0-20.

In a ninth aspect, the present invention provides a drug for radionuclide conjugation, comprising the following formula (VII):

in,

Ld' is selected from C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

^RA and ^RB are each independently optionally covalently linked to a chelating group and/or an albumin binding unit; wherein ^RA and ^RB are each independently selected from hydrogen or one or a combination of the following groups: _C1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and _C1-10 alkyl; wherein ^RA and ^RB are not simultaneously hydrogen;

^RC is optionally covalently linked to a chelating group, an albumin binding unit, or a combination thereof; wherein ^RC is selected from one or a combination of the following: a hydroxyl group, a natural or non-natural amino acid fragment, and a C _1-30 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NR ⁴ -, -(CO)-, -(C=S)-, and a C _6-10 arylene group, and the alkyl and arylene groups are optionally substituted by at least one substituent selected from the group consisting of hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

Said ^R4 is selected from hydrogen or _C1-10 alkyl, wherein the carbon chain unit of said alkyl is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, and said alkyl is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amino and sulfonyl- _C1-10 alkyl.

In a tenth aspect, the present invention further provides use of the radionuclide conjugates of the first to second aspects, the compounds of the third to fifth aspects, and the radionuclide conjugates of the sixth to ninth aspects of the present invention in preparing radionuclide conjugates.

In an eleventh aspect, the present invention provides a radionuclide conjugate comprising a radionuclide and the radionuclide conjugates of the first to second aspects, the compounds of the third to fifth aspects, or the radionuclide conjugates of the sixth to ninth aspects of the present invention.

In a twelfth aspect, the present invention provides a pharmaceutical composition comprising the radionuclide conjugate according to the eleventh aspect of the present invention, and optionally at least one pharmaceutically acceptable carrier.

In a thirteenth aspect, the present invention provides use of the radionuclide conjugate according to the eleventh aspect of the present invention or the pharmaceutical composition according to the twelfth aspect of the present invention for medical treatment and/or diagnosis.

In a fourteenth aspect, the present invention provides use of the radionuclide conjugate of the eleventh aspect of the present invention or the pharmaceutical composition of the twelfth aspect of the present invention in the preparation of a therapeutic nuclear medicine or a diagnostic nuclear medicine;

The therapeutic nuclear medicine or diagnostic nuclear medicine is used to treat or diagnose malignant lymphoma, testicular seminoma, Wilms' tumor, neuroblastoma, medulloblastoma, Ewing sarcoma, small cell lung cancer, head and neck squamous cell carcinoma, esophageal squamous cell carcinoma, lung squamous cell carcinoma, breast cancer, cervical cancer, skin cancer, gastrointestinal adenocarcinoma, pancreatic cancer, prostate cancer, fibrosarcoma, liposarcoma or rhabdomyosarcoma.

In a fifteenth aspect, the present invention provides a method for diagnosing, delaying or treating a disease, comprising administering to a subject in need thereof an effective amount of the radionuclide conjugate of the eleventh aspect of the present invention or the pharmaceutical composition of the twelfth aspect of the present invention;

The diseases include malignant lymphoma, testicular seminoma, Wilms' tumor, neuroblastoma, medulloblastoma, Ewing sarcoma, small cell lung cancer, head and neck squamous cell carcinoma, esophageal squamous cell carcinoma, lung squamous cell carcinoma, breast cancer, cervical cancer, skin cancer, gastrointestinal adenocarcinoma, pancreatic cancer, prostate cancer, fibrosarcoma, liposarcoma or rhabdomyosarcoma.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows the HIC-HPLC detection results of the conjugate Ab62-LP1.

FIG2 shows the SEC-HPLC detection results of the conjugate Ab62-LP1.

FIG3 shows the results of the binding test between the conjugate and cells.

FIG4 shows the results of the cellular internalization assay of the conjugate.

FIG5 shows the radio-HPLC chemical purity test results of the radionuclide conjugate ⁶⁸ Ga-Ab62-LP1.

FIG6 shows the radio-HPLC radioactivity purity test results of the radionuclide conjugate ⁶⁸ Ga-Ab62-LP1.

FIG7 shows the radio-HPLC chemical purity test results of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP1 prepared by the method of Preparation 1 in Example 24.

FIG8 shows the radio-HPLC radioactivity purity test results of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP1 prepared by the method of Preparation 1 in Example 24.

FIG9 shows the radio-HPLC chemical purity test results of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP1 prepared by the method of Preparation 2 in Example 24.

FIG10 shows the radio-HPLC radioactivity purity test results of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP1 prepared by the method of Preparation 2 in Example 24.

FIG11 shows the radio-HPLC chemical purity test results of the radionuclide conjugate ⁶⁴ Cu-Ab62-LP2.

FIG12 shows the radio-HPLC radioactivity purity test results of the radionuclide conjugate ⁶⁴ Cu-Ab62-LP2.

FIG13 shows the stability results of radionuclide conjugates.

FIG14 shows the results of cellular uptake and internalization of radionuclide conjugates.

DETAILED DESCRIPTION

General Definitions and Terminology

Unless otherwise indicated, scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, terms related to chemical synthesis, molecular biology, and laboratory procedures used herein are those widely used in the relevant fields and are common procedures. To facilitate a better understanding of the present invention, definitions and explanations of relevant terms are provided below.

As used herein, "at least one" or "one or more" may mean 1, 2, 3, 4, 5, 6, 7, 8 or more.

As used herein, the expressions "comprises," "comprising," "containing," and "having" are open ended and mean the inclusion of the listed elements, steps, or components but not the exclusion of other unlisted elements, steps, or components. The expression "consisting of excludes any element, step, or component not specified. The expression "consisting essentially of means that the scope is limited to the specified elements, steps, or components, plus optional elements, steps, or components that do not significantly affect the basic and novel properties of the claimed subject matter. It should be understood that the expressions "consisting essentially of" and "consisting of are encompassed within the meaning of the expression "comprising."

As used herein, the term "and/or" connecting multiple elements should be understood to include both individual and combined options. In other words, "and/or" includes "and" and "or." For example, A and/or B includes A, B, and A+B. A, B, and/or C includes A, B, C, and any combination thereof, such as A+B, A+C, B+C, and A+B+C. More elements qualified with "and/or" are understood in a similar manner and include any one thereof and any combination thereof.

Unless otherwise indicated, any numerical value or numerical range, such as a concentration or concentration range, is to be understood as being modified in all cases by the term "about". Thus, numerical values generally include ±10% of the stated value. As used herein, the use of numerical ranges explicitly includes all possible subranges, all individual numerical values within that range, including integers and fractions within that range, unless the context clearly indicates otherwise.

The term "optionally" means that the subsequently described event may or may not occur, and that the description includes instances where said event or circumstance occurs or does not occur.

The term "alkyl" refers to a straight or branched saturated aliphatic hydrocarbon group consisting of carbon atoms and hydrogen atoms, which is connected to the rest of the molecule by a single bond. The alkyl group can have 1 to 60 carbon atoms, for example, having 1 to 20 carbon atoms refers to a "C ₁ -C ₂₀ alkyl (C _1-20 alkyl)", such as C ₁ -C ₄ alkyl, C ₁ -C ₃ alkyl, C ₁ -C ₂ alkyl, C ₃ alkyl, C ₄ alkyl, C ₃ -C ₆ alkyl. Non-limiting examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, or isomers thereof.

The term "heteroalkyl" refers to a stable linear or branched alkyl radical or combination thereof consisting of a certain number of carbon atoms and at least one heteroatom or heteroatom group. In some embodiments, the heteroatom is selected from B, O, N, and S, wherein the nitrogen and sulfur atoms are optionally oxidized and the nitrogen heteroatom is optionally quaternized.

The term "alkynyl" refers to a straight-chain or branched hydrocarbon group containing one or more carbon-carbon triple bonds, which may be located at any position of the group.

The term "cycloalkyl" includes any stable cyclic alkyl group, including monocyclic, bicyclic, or tricyclic ring systems, wherein bicyclic and tricyclic ring systems include spirocyclic, fused, and bridged rings. The term "heterocycloalkyl" refers to a cyclized "heteroalkyl" group, including monocyclic, bicyclic, and tricyclic ring systems, wherein bicyclic and tricyclic ring systems include spirocyclic, fused, and bridged rings. In some embodiments, the heterocycloalkyl group is a 3-10 membered heterocycloalkyl group; in other embodiments, the heterocycloalkyl group is a 5-6 membered heterocycloalkyl group. Examples of heterocycloalkyl include, but are not limited to, azetidinyl, oxetanyl, thietanyl, pyrrolidinyl, 1H-pyrrole-2,5-dione, pyrazolidinyl, imidazolidinyl, tetrahydrothiophenyl (including tetrahydrothiophen-2-yl and tetrahydrothiophen-3-yl, etc.), tetrahydrofuranyl (including tetrahydrofuran-2-yl, etc.), tetrahydropyranyl, piperidinyl (including 1-piperidinyl, 2-piperidinyl and 3-piperidinyl, etc.), piperazinyl (including 1-piperazinyl and 2-piperazinyl, etc.), morpholinyl (including 3-morpholinyl and 4-morpholinyl, etc.), dioxanyl, dithianyl, isoxazolidinyl, isothiazolidinyl, 1,2-oxazinyl, 1,2-thiazinyl, hexahydropyridazinyl, homopiperazinyl, homopiperidinyl, or oxepanyl.

The term "aryl" refers to a polyunsaturated carbocyclic ring system which may be a monocyclic, bicyclic or polycyclic ring system, wherein at least one ring is aromatic, the rings of said bicyclic and polycyclic ring systems being fused together.

The term "heteroaryl" refers to an aryl group containing 1, 2, 3 or 4 heteroatoms independently selected from B, N, O and S, which can be a monocyclic, bicyclic or tricyclic ring system. In some embodiments, the heteroaryl group is a 5-10 membered heteroaryl group. In other embodiments, the heteroaryl group is a 5-6 membered heteroaryl group. Examples of the heteroaryl group include, but are not limited to, pyrrolyl (including N-pyrrolyl, 2-pyrrolyl and 3-pyrrolyl), pyrazolyl (including 2-pyrazolyl and 3-pyrazolyl), imidazolyl (including N-imidazolyl, 2-imidazolyl, 4-imidazolyl and 5-imidazolyl), oxazolyl (including 2-oxazolyl, 4-oxazolyl and 5-oxazolyl), triazolyl (1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl and 4H-1,2,4-triazolyl), tetrazolyl, isoxazolyl (3-isoxazolyl, 4-isoxazolyl and 5-isoxazolyl), thiazolyl (including 2-thiazolyl, 4-thiazolyl and 5-thiazolyl), The substituents of any one of the heteroaryl ring systems are selected from the acceptable substituents described in the present invention.

A divalent free radical is a radical obtained by removing a hydrogen atom from a carbon atom with a free valence electron of a corresponding monovalent free radical. A divalent free radical has two attachment sites connected to the rest of the molecule. For example, "alkylene" or "alkylene group" refers to a saturated straight or branched divalent hydrocarbon radical. Examples of "alkylene" include, but are _not limited to, methylene _{( -CH2-} ), ethylene ( _-C2H4- ), propylene ( _-C3H6- ), butylene ( _-C4H8- ), pentylene ( _-C5H10- ), hexylene ( _-C6H12- ), 1-methylethylene (-CH _{( CH3} ) _CH2- ), 2-methylethylene ( _-CH2CH ( _CH3 ) _- ), methylpropylene or ethylpropylene. "Cycloalkylene" refers to a divalent cyclic hydrocarbon radical of _a saturated cycloalkyl group. "Heterocycloalkylene" refers to a divalent radical of a heterocycloalkyl group. "Arylene" refers to a divalent radical of an aryl group, such as phenylene. "Heteroarylene" refers to a divalent radical of a heteroaryl group.

As used herein, "antibody" refers to an immunoglobulin or its fragment, which specifically binds to an antigenic epitope through at least one antigen binding site. Antibody encompasses antibody fragments. As used herein, the term "antibody" includes synthetic antibodies, recombinantly produced antibodies, multispecific antibodies (e.g., bispecific antibodies), human antibodies, non-human antibodies, humanized antibodies, single domain antibodies, chimeric antibodies, intracellular antibodies, and antibody fragments, such as, but not limited to, Fab fragments, Fab' fragments, F(ab') ₂ fragments, Fv fragments, disulfide-linked Fv (dsFv), Fd fragments, Fd' fragments, single-chain Fv (scFv), single-chain Fab (scFab), diabodies, anti-idiotypic (anti-Id) antibodies, or antibodies of any of the above antibodies. Antibodies provided herein include members of any immunoglobulin type (e.g., IgG, IgM, IgD, IgE, IgA, and IgY), any class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2), or subclass (e.g., IgG2a and IgG2b). In a preferred embodiment, the antibodies of the invention are single domain antibodies.

As used herein, an "antibody fragment" or "antigen-binding fragment" of an antibody refers to any portion of a full-length antibody that is less than full-length but contains at least a portion of the variable region (e.g., one or more CDRs and/or one or more antigen-binding sites) of the antibody that binds to an antigen and thus retains binding specificity and at least a portion of the specific binding ability of the full-length antibody. Thus, an antigen-binding fragment refers to an antibody fragment that contains an antigen-binding portion that binds to the same antigen as the antibody from which the antibody fragment was derived. Antibody fragments include antibody derivatives produced by enzymatic treatment of full-length antibodies, as well as synthetically produced derivatives, such as recombinantly produced derivatives. Antibodies include antibody fragments. Examples of antibody fragments include, but are not limited to, Fab, Fab', F(ab') ₂ , single-chain Fv (scFv), Fv, dsFv, diabodies, Fd and Fd' fragments, and other fragments, including modified fragments (see, e.g., Methods in Molecular Biology, Vol 207: Recombinant Antibodies for Cancer Therapy Methods and Protocols (2003); Chapter 1; p 3-25, Kipriyanov). The fragments can include multiple chains linked together, for example, by disulfide bonds and/or by peptide linkers. Antibody fragments generally contain at least or about 50 amino acids, and typically at least or about 200 amino acids. Antigen-binding fragments include any antibody fragment that, when inserted into an antibody framework (e.g., by replacing the corresponding regions), results in an antibody that immunospecifically binds to an antigen.

As used herein, "immunoglobulin single variable domain" or "single variable domain" refers to a single variable region (variable domain) with antigen-binding activity. Unlike conventional antibodies, which are composed of a pair of VH and VL functional antigen-binding units, single variable domains can form functional antigen-binding units on their own. Single variable domains can be derived from naturally occurring light chain-free antibodies, such as the variable domain of heavy chain antibodies (VHH) of camelids (such as camels and alpacas) and the single variable domain of shark neoantigen receptors (IgNAR variable single-domain, VNAR), or they can be screened from full-length antibodies, such as light chain variable domains and heavy chain variable domains with antigen-binding activity in human antibodies. VHHs typically contain three highly variable complementarity determining regions (CDRs) and four relatively conserved framework regions (FRs), connected from N-terminus to C-terminus in the order of FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4.

As used herein, "single-domain antibody (sdAb)" or "nanobody" refers to an antibody that comprises a single immunoglobulin variable domain (single variable domain) as a functional antigen-binding fragment. Similar to the variable region of a full-length antibody, a single variable domain typically comprises CDR1, CDR2, and CDR3 that form the antigen-binding site, as well as a supporting framework region. Unlike full-length antibodies that typically comprise two heavy chains and two light chains, single-domain antibodies typically comprise a single peptide chain consisting of a single variable domain with a molecular weight of only about 15 kDa. The single variable domain can, for example, be the variable domain of a heavy-chain antibody (VHH) of an alpaca, the IgNAR variable domain of a shark, or the variable domain of a human light-chain antibody.

As used herein, the terms "single-chain antibody,""single-chainFv," or "scFv" refer to molecules comprising an antibody heavy chain variable domain ( _VH ) and an antibody light chain variable domain ( _VL ) connected by a linker. Such scFv molecules can have the general structure NH2 _- VL-Linker-VH-COOH or NH2 _- VH-Linker-VL-COOH.

The amino acid sequences of the CDRs in the present invention are shown according to the Kabat definition rules. However, it is well known to those skilled in the art that the CDR of an antibody can be defined in the art by a variety of methods, such as Chothia based on the three-dimensional structure of the antibody and the topology of the CDR loop (see, for example, Chothia, C. et al., Nature, 342, 877-883 (1989); and Al-Lazikani, B. et al., J. Mol. Biol., 273, 927-948 (1997)), Kabat based on antibody sequence variability (see, for example, Kabat, E.A. et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242), AbM (Martin, A.C.R. and J. Allen (2007) “Bioinformatics tools for antibody engineering,” in S. Dübel (ed.), Handbook of Therapeutic Antibodies. Weinheim: Wiley-VCH Verlag, pp. 95–118), Contact (MacCallum, R. M. et al., (1996) J. Mol. Biol. 262: 732–745), IMGT (Lefranc, M.-P., 2011 (6), IMGT, the International ImMunoGeneTics Information System Cold Spring Harb Protoc.; and Lefranc, M.-P. et al., Dev. Comp. Immunol., 27, 55–77 (2003)), and North CDR definitions based on affinity propagation clustering using a large number of crystal structures. In this article, multiple CDR numbering systems can be used for the same variable region, such as Chothia, Abm, Kabat, Contact and IMGT. It will be understood by those skilled in the art that although the CDRs defined by different numbering systems may be different, the CDRs corresponding to the same numbering system represent effective antigen binding sites that can bind to antigen epitopes. Unless otherwise specified, the terms "CDR" and "complementarity determining region" of a given antibody or a region thereof (such as a variable region) should be understood to cover the complementary determining region defined by any of the above-mentioned known schemes described by the present invention. Although the scope of protection claimed in the claims of the present invention is based on the sequences shown in the Kabat definition rules, the amino acid sequences corresponding to the definition rules of other CDRs should also fall within the scope of protection of the present invention.

Thus, when referring to antibodies defined by specific CDR sequences defined herein, the scope of said antibodies also encompasses antibodies whose variable region sequences comprise said specific CDR sequences, but whose declared CDR boundaries differ from the specific CDR boundaries defined herein due to the application of a different scheme (e.g., a different assignment system rule or combination).

As used herein, the terms "framework region" and "framework region" are used interchangeably. As used herein, the terms "framework region," "framework region," or "FR" residues refer to those amino acid residues in the antibody variable region excluding the CDR sequences as defined above.

As used herein, the term "disulfide bond" includes a covalent bond formed between two sulfur atoms. The amino acid cysteine contains a sulfhydryl group that can form a disulfide bond or bridge a second sulfhydryl group.

As used herein, "percent (%) sequence identity" or "sequence identity" of amino acid sequences has the art-recognized definition of the percentage of identity between two polypeptide sequences as determined by sequence alignment (e.g., by manual inspection or a publicly known algorithm). This can be determined using methods known to those skilled in the art, for example, using publicly available computer software such as BLAST, BLAST-2, Clustal Omega, and FASTA software.

Non-essential regions in a polypeptide can be modified, for example, by substitution, addition and/or deletion of one or more amino acids, without altering the function of the polypeptide. Suitable conservative amino acid substitutions in peptides or proteins are known to those skilled in the art and can generally be made without altering the biological activity of the resulting molecule. Generally, those skilled in the art recognize that single amino acid substitutions in non-essential regions of a polypeptide do not substantially alter biological activity (see, e.g., Watson et al., Molecular Biology of the Gene, 4th Edition, 1987, The Benjamin/Cummings Pub.co., p. 224).

"Spacer (or SP)" refers to a structure located between different structural modules that can spatially separate the structural modules. The definition of a spacer does not limit whether it has a certain function, nor does it limit whether it can be cut or degraded in vivo. Examples of spacers include, but are not limited to, amino acids and non-amino acid structures, wherein the non-amino acid structure can be, but is not limited to, an amino acid derivative or analog. "Spacer sequence" refers to an amino acid sequence that serves as a spacer, examples of which include, but are not limited to, a single amino acid, a sequence containing multiple amino acids, for example, a sequence containing two amino acids, such as GA, or for example, GGGGS (SEQ ID No: 14), GGGGSGGGGS (SEQ ID NO: 15), GGGGSGGGGSGGGGS (SEQ ID NO: 16), etc.

As used herein, the term "amino acid" includes "natural amino acids" and "unnatural amino acids."

The term "natural amino acids" refers to amino acids, which are protein-building amino acids, including the common twenty amino acids (alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine), as well as the less common selenocysteine and pyrrolysine.

As used herein, the term "unnatural amino acid" refers to an amino acid that is not a protein-forming amino acid. Specifically, the term refers to an amino acid that is not a natural amino acid as defined above.

"Affinity" or "binding affinity" is a measure of the strength of the non-covalent binding between an antibody and an antigen. Affinity can be determined using conventional techniques known in the art, such as biofilm interferometry (using, for example, the Octet Fortebio assay system), radioimmunoassay, surface plasmon resonance (SPR), enzyme-linked immunosorbent assay (ELISA), or flow cytometry (FACS). Binding affinity is typically measured by the equilibrium dissociation constant (KD), which is the ratio of the "off-rate" (koff) to the "on-rate" (kon), and is used to assess and rank the strength of bimolecular interactions. The "on-rate" (Kon) characterizes the rate at which a ligand binds to its target, and the "off-rate" (Koff) characterizes the rate at which a ligand dissociates from its target. KD (Koff/Kon) and binding affinity are inversely proportional.

"Specific binding" generally refers to a binding molecule, such as an antibody or a fragment, variant, or derivative thereof, that binds to an epitope through its antigen binding domain, and this binding requires some complementarity between the antigen binding domain and the epitope. By this definition, a binding molecule is said to "specifically bind" to an epitope when it is easier to bind to an epitope through its antigen binding domain than to a random, unrelated epitope. The term "specificity" is used herein to qualitatively analyze the relative affinity of an antibody for binding to an epitope. For example, it can be considered that binding molecule "A" has a higher specificity for a given epitope than binding molecule "B," or it can be said that binding molecule "A" specifically binds to epitope "C" with a higher specificity than its specificity for a related epitope "D."

If a binding molecule, e.g., an antibody, or fragment, variant, or derivative thereof, preferentially binds to an epitope to the extent that it blocks binding of the reference antibody or antigen-binding fragment to the epitope, then the binding molecule, e.g., an antibody, or fragment, variant, or derivative thereof, is said to competitively inhibit binding of the reference antibody or antigen-binding fragment to a given epitope. Competitive inhibition can be determined by any method known in the art, e.g., a competition ELISA assay. The binding molecule can be said to competitively inhibit binding of the reference antibody or antigen-binding fragment to a given epitope by at least 90%, at least 80%, at least 70%, at least 60%, or at least 50%.

Terms such as "treating" or "treating" or "to treat" or "alleviating" or "to alleviate" refer to therapeutic measures that cure, alleviate, reduce the symptoms of an existing, diagnosed pathological condition or disorder, and/or arrest or slow the progression of an existing, diagnosed pathological condition or disorder. Terms such as "preventing," "preventing," "avoiding," "containment," and the like refer to preventative or prophylactic measures that prevent the progression of an undiagnosed target pathological condition or disorder. Thus, a "subject in need thereof" can include a subject already suffering from a disease; a subject susceptible to a disease; and a subject in need of prevention of a disease.

As used herein, "therapeutic effect" refers to an effect resulting from treatment of a subject that alters, typically ameliorates or improves the symptoms of a disease or condition, or cures the disease or condition.

As used herein, the term "effective amount" refers to an amount of an antibody, polypeptide, polynucleotide, small organic molecule or other drug that is effective for "treating," "preventing" or "alleviating" a disease or condition in a subject or mammal. In the case of cancer, an effective amount of a drug can reduce the number of cancer cells; block or stop cancer cell division, reduce or block the increase in tumor size; inhibit, for example, suppress, block, prevent, stop, delay or reverse cancer cell infiltration to peripheral organs, including, for example, the spread of cancer to soft tissue and bone; inhibit, for example, suppress, block, prevent, shrink, stop, delay or reverse tumor metastasis; inhibit, for example, suppress, block, prevent, stop, delay or reverse tumor growth; alleviate one or more symptoms associated with cancer to some extent, reduce morbidity and mortality; improve quality of life; or a combination of these effects. To the extent that a drug prevents growth and/or kills existing cancer cells, it can refer to cytostatic and/or cytotoxic.

As used herein, the terms "subject," "patient," or "individual" generally include humans and non-human animals, and preferably include mammals (e.g., non-human primates, including marmosets, tamarins, spider monkeys, owl monkeys, vervet monkeys, squirrel monkeys, and baboons, macaques, chimpanzees, orangutans, gorillas; cows; horses; sheep; pigs; chickens; cats; dogs; mice; rats; rabbits; guinea pigs, etc.), including chimeric and transgenic animals and disease models. The term "subject" preferably refers to a non-human primate or a human, most preferably a human.

As used herein, the term "radionuclide" (or "radioisotope") refers to an isotope of natural or artificial origin having an unstable neutron to proton ratio that decomposes with the emission of microparticles, i.e., protons (α-radiation) or electrons (β-radiation) or electromagnetic radiation (γ-radiation). Such radionuclides can preferably be used for cancer imaging or treatment.

The antibody numbers used herein (such as Ab60, Ab61, Ab62 and Ab63, etc.) are only used to distinguish or identify antibodies or products, and are not intended to indicate that such identification is a feature of the antibodies or products of the present invention. It will be understood by those skilled in the art that, for example, for the purpose of distinguishing or identifying, other antibodies or products may also use such identification, but do not refer to identical or equivalent antibodies or products. Similarly, the similar numbering or identification used in the embodiments is only for illustrative convenience, and the antibodies or products of the present invention are limited by the features described in the appended claims.

As used herein, _" each carbon chain unit is replaced by a substituent" means that the _-CH2- on the carbon chain backbone is replaced by a divalent substituent. For example, -CH2- _CH2 - _CH2 - _CH2- can be replaced by -O- to -O-CH2 _{-CH2 -CH2-} , -CH2 _{- O} - _CH2 - _CH2- , _-CH2 - _CH2 -O- _CH2- or -O- _CH2 -O- _CH2- .

Conjugates of the present invention

In one aspect, the present invention relates to a conjugate comprising a covalently linked targeting moiety A and a loading unit, wherein the targeting moiety A and the loading unit form a covalent bond with a linker catalyzed by a ligase; the loading unit comprises an albumin binding unit (Q) and a chelating group (D and/or D') for a radionuclide. In some embodiments, the albumin binding unit is a small molecule.

In some embodiments, the ligase is a formylglycine generating enzyme, a transglutaminase, a tyrosinase, or a sortase enzyme. In some embodiments, the ligase is an asparagine ligase (PAL). In some embodiments, the asparagine ligase is a Singzyme or a Butelase. In some embodiments, the asparagine ligase recognizes amino acid sequences N-X-L and GI, where X is any amino acid.

In some embodiments, Sortase is sortase A (SrtA), sortase B (SrtB), sortase C (SrtC), sortase D (SrtD), sortase E (SrtE) or sortase F (SrtF), but is not limited thereto.

The term "sortase" or "sortase enzyme" as used herein refers to an enzyme having sortase activity to catalyze a transpeptidation reaction, including, for example, class A, class B, class C, class D, class E, and class F sortases of the sortase enzyme superfamily (see, for example, Dramsi, et al., Sorting sortases: a nomenclature proposal for the various sortases of Gram-positive bacteria, Research in Microbiology, (2005), 1 56:289–297; Bradshaw, et al., Molecular features of the sortase enzyme family, FEBS Journal, (2015), 282:2097–2114; Malik and Kim, A comprehensive in silico analysis of sortase superfamily, J Microbiol., (2019), 57(6):431-443; and EP3647419A1), but not limited thereto. Such enzymes may be referred to as SrtA, SrtB, SrtC, SrtD, SrtE, or SrtF, but not limited thereto. Sortases may be naturally occurring or engineered. Naturally occurring sortases can be found in a variety of Gram-positive bacteria, such as any strain, species, or subspecies of the genera Streptococcus (e.g., Streptococcus pneumoniae and Streptococcus pyogenes), Staphylococcus (e.g., Staphylococcus argenteus and Staphylococcus aureus), Bacillus (e.g., Bacillus anthracis), and Listeria (e.g., Listeria monocytogenes), but are not limited thereto. Engineered sortases, such as sortase variants having one or more amino acid residue substitutions, deletions, or insertions, can be obtained from their natural counterparts by methods known in the art, such as protein engineering and chemical synthesis. Other variants of any wild-type sortase known in the art (such as those with one or more active groups or tags) are also contemplated. Provided that the variant has the same or similar function as the wild-type sortase. Those skilled in the art will readily be able to identify sortases and classify them into specific categories based on their sequence and other characteristics. However, the definition of sortase is not limited to any classification method or nomenclature system.

On the other hand, the present invention relates to a conjugate comprising a covalently linked targeting portion A and a loading unit, wherein the targeting portion A and the loading unit form a covalent bond with a linker by chemical coupling; the loading unit comprises an albumin binding unit (Q) and a chelating group (D and/or D') of a radionuclide.

In some embodiments, the targeting moiety is selected from a ligand, a polypeptide, an antibody, or an antigen-binding fragment thereof.

In some embodiments, the targeting moiety is an antibody or an antigen-binding fragment thereof; preferably, the antibody is a single domain antibody or a single chain antibody. In some embodiments, the targeting moiety is a polypeptide. In some embodiments, the polypeptide is a cyclic peptide. In some embodiments, the targeting moiety comprises a polypeptide and a covalently bound molecular backbone.

In one aspect, the present invention relates to a radionuclide conjugate comprising the following structure:

in,

is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling;

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

_La is connected to the targeting moiety and a coupling unit of a linker G, each _La is independently selected from the following 1), 2) or a combination thereof:

1) one or more natural amino acids or oligomeric natural amino acids having a degree of polymerization of 2-20; 2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _{C 2-6 alkynyl} , C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene, and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene, and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl, and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch part with branching function, directly or indirectly connected to Q and D; wherein,

Each G is independently selected from the following 3), 4) or a combination thereof:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20;

o is an integer or non-integer greater than 0 and less than 20.

In another aspect, the present invention provides a radionuclide conjugate comprising the following structure:

in,

is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling;

Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each _La is independently selected from the following 1), 2) or a combination thereof:

1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, C _2-6 alkynyl, C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, k2 are each independently an integer from 0 to 10;

o is an integer greater than 0 and less than 10 or a non-integer.

The present invention can use ligase dependent conjugation (LDC) technology to Coupled with the rest of the compound of formula (I). Here, ligase refers to a transpeptidase, including but not limited to various natural Sortase enzymes (including A, B, C, D, L. plantarum Sortase, etc., see patents US20110321183A and WO2022160156A for details) and various novel transpeptidases that have been preferably modified. The coupling reaction is achieved by bioenzyme catalysis, and the reaction conditions are mild, which reduces the physical and chemical damage of the coupling process to the antibody, and the preparation process and process are more optimized, easy to industrialize and upgrade, and conducive to the quality control of the coupled product.

In some embodiments, the targeting moiety In some embodiments, the targeting moiety forms a covalent bond with the loading unit by enzyme coupling. Represents an unmodified or modified targeting moiety. In some embodiments, represents the modified targeting portion, the purpose of which is to allow the ligase to act on the The _La of the load unit can be formed by reacting with La _' . In some embodiments, Contains a ligase recognition substrate, and L _a' comprises a ligase recognition substrate. In some embodiments, In some embodiments, L _{a '} comprises a ligase donor recognition substrate, In some embodiments, The invention comprises a spacer (SP) and a ligase donor substrate recognition sequence connected in sequence. In some embodiments, the spacer is selected from GA, GGGGS, GGGGSGGGGS or GGGGSGGGGSGGGGS; preferably, the spacer is GA.

In some embodiments, the targeting moiety It naturally contains _La moieties, such as Cys, Lys, Gln, that can react with La _' to form a cargo unit.

In some embodiments, the ligase is a Sortase enzyme. In some embodiments, the targeting moiety The C-terminus or N-terminus of the ligase is modified to include a spacer (SP) and a ligase donor substrate recognition sequence.

In some embodiments, the spacer is selected from GA, GGGGS, GGGGSGGGGS, or GGGGSGGGGSGGGGS; preferably, the spacer is GA.

In some embodiments, the ligase donor substrate recognition sequence is LPX ₁ TGX ₂ (SEQ ID NO: 17), wherein X ₁ is any natural or unnatural amino acid, and X ₂ is absent or is an amino acid fragment comprising 1-10 amino acids. In particular, the ligase donor substrate recognition sequence is LPETGG (SEQ ID NO: 18).

The ligase used in the present invention may also include transglutaminase, formylglycine generating enzyme, tyrosinase and asparagine ligase.

In some embodiments, transglutaminase (TGase) catalyzes the reaction of glutamine with lysine and its derivatives, and the targeting moiety of the present invention can be achieved by TGase. Site-specific coupling with the load unit. TGase cannot recognize the naturally occurring glutamine in the constant region of glycosylated antibodies and has high specificity. TGase transfers the transglutaminase receptor substrate recognition structure contained in the load unit to the transglutaminase donor substrate recognition structure. In some embodiments, the targeting moiety Containing the LLQG (SEQ ID NO: 21) peptide segment, TGase can specifically recognize the glutamine in the LLQG peptide segment sequence, so that the targeting portion and the load unit are coupled. In some embodiments, under the action of the ligase, the targeting portion of formula (I) By reacting with La _' to form the loading unit _La , the targeting moiety and L _a' respectively comprise a transglutaminase donor substrate recognition structure or a transglutaminase acceptor substrate recognition structure. In some embodiments, the transglutaminase donor substrate recognition structure comprises glutamine. In some embodiments, the targeting moiety Contains glutamine. In some embodiments, the targeting moiety Modification is performed by introducing glutamine. In some embodiments, the modified targeting moiety Contains peptide LLQG. In some embodiments, the transglutaminase receptor substrate recognition structure is -NH _2. In some embodiments, L _a' comprises -NH ₂ , for example, L _a' comprises -C _1-10 alkylene-NH ₂ or lysine. In other embodiments, the targeting moiety Contains glutamine.

Formylglycine generating enzyme (FGE) can specifically recognize the CX ₃ PX ₄ R pentapeptide sequence, wherein X ₃ and X ₄ are any natural or non-natural amino acids, and the cysteine residue is replaced by an aldehyde group. The aldehyde group can further react with the substrate recognition structure of the formylglycine generating enzyme donor to generate a stable structure. For example, the aldehyde group reacts with dimethylated 2-(hydrazinomethyl)-3-indole to form a stable carbon-carbon bond through tetrahydroisoquinoline synthesis (HIPS) reaction at a pH close to neutral. In some embodiments, under the action of the ligase, the targeting portion of formula (I) By reacting with La _' to form the loading unit _La , the targeting moiety In some embodiments, the targeting moiety comprises a C-terminal or N-terminal modification, which in turn comprises a spacer (SP) and a ligase donor substrate recognition sequence. and L _a' respectively comprise a formylglycine generating enzyme donor substrate recognition structure or a formylglycine generating enzyme acceptor substrate recognition structure. In some embodiments, the formylglycine generating enzyme donor substrate recognition structure comprises a recognition sequence CX ₃ PX ₄ R, wherein X ₃ and X ₄ are any natural or unnatural amino acids. In some embodiments, the formylglycine generating enzyme acceptor substrate recognition structure comprises a structure that can form a stable reaction product with an aldehyde group. In some embodiments, L _a' comprises The wavy lines represent sites of attachment to other structures of the loading unit. It comprises a recognition sequence CX ₃ PX ₄ R, wherein X ₃ and X ₄ are any natural or unnatural amino acids.

Tyrosinase oxidizes tyrosine to 1,2-quinone, which can undergo cycloaddition reactions with various structures. For example, cycloaddition reactions occur with various bicyclo[6.1.0]nonyne (BCN) derivatives. In some embodiments, under the action of the ligase, the targeting moiety of formula (I) By reacting with La _' to form the loading unit _La , the targeting moiety In some embodiments, the modified targeting moiety comprises a ligase donor substrate recognition sequence. and L _a' respectively comprise a tyrosinase donor substrate recognition structure or a tyrosinase acceptor substrate recognition structure. In some embodiments, the tyrosinase donor substrate recognition structure comprises tyrosine. In some embodiments, the targeting moiety Contains tyrosine. In some embodiments, the targeting moiety Modification is performed by introducing tyrosine. In some embodiments, the modified targeting moiety Contains tyrosine. In some embodiments, the tyrosine receptor substrate recognition structure includes any structure that can undergo a cycloaddition reaction with 1,2-quinone to form a stable product. In some embodiments, L _a' comprises a bicyclo[6.1.0]nonyne structure. In other embodiments, the targeting moiety Contains tyrosine.

The asparagine ligase of the present invention includes Singzyme and butelase. Singzyme specifically recognizes the ligase donor substrate recognition sequence NX ₅ L, wherein X ₅ is any natural or unnatural amino acid, so that it can be ligated with the ligase acceptor substrate recognition sequence GI under its mediation.

Butelase is an asparagine ligase derived from butterfly pea. It can specifically recognize the Asn-His-Val (NHV) amino acid sequence at the carboxyl terminus of a polypeptide and catalyze the ligation reaction between the Asn residue on this sequence and any type of amino acid residue at the amino terminus of the same or another polypeptide to form a peptide bond.

In some embodiments, under the action of a ligase, the targeting moiety of formula (I) By reacting with La _' to form the loading unit _La , the targeting moiety and La _' respectively comprise an asparagine ligase donor substrate recognition structure or an asparagine ligase acceptor substrate recognition structure. In some embodiments, the targeting moiety The C-terminus or N-terminus of the asparagine ligase is modified to include a spacer (SP) and a ligase donor substrate recognition sequence. In some embodiments, the asparagine ligase donor substrate recognition structure includes a recognition sequence NX ₅ L, wherein X ₅ is any natural or unnatural amino acid, and a recognition sequence NHV. In other embodiments, the asparagine ligase acceptor substrate recognition structure includes an amino acid fragment GI. In some embodiments, L _a' includes an amino acid fragment GI. In other embodiments, the targeting moiety It comprises recognition sequences NX ₅ L and NHV, wherein X ₅ is any natural or unnatural amino acid.

The targeting moiety of formula (I) of the present invention The target moiety and the load unit can also form a covalent bond by chemical coupling. By reacting with La _' to form the loading unit _La , the targeting moiety Contains lysine and is chemically coupled to L _a' through it. L _a' contains a group capable of reacting with an amino group, such as a carboxyl group, a carbonyl group, an allyl group, a hydroxyl group, a thiol group, an activated ester, etc. In some embodiments, L _a' comprises the following structure:

The wavy lines indicate the sites of connection to other structures of the payload unit.

In other embodiments, the targeting moiety By reacting with La _' to form the loading unit _La , the targeting moiety Contains cysteine and is chemically coupled to L _a' through cysteine. L _a' contains a group capable of reacting with a sulfhydryl group, for example, a hydroxyl group, a carboxyl group, a maleimide group, etc. In some embodiments, L _a' comprises the following structure:

In some embodiments, the targeting moiety is selected from a ligand, polypeptide, antibody or antigen-binding fragment thereof that specifically binds to the target; preferably, the targeting moiety is an antibody or an antigen-binding fragment thereof; more preferably, the targeting moiety In a specific embodiment, the targeting moiety is selected from a single domain antibody or a single chain antibody. is an anti-prostate-specific membrane antigen (PSMA) antibody; preferably, is an anti-PSMA single domain antibody. In a specific embodiment, the targeting moiety is an anti-epidermal growth factor receptor 2 (HER2) antibody. In another specific embodiment, the targeting moiety It is an anti-Delta-like ligand 3 (DLL3) antibody.

In some embodiments, the targeting moiety It comprises HCDR1 as shown in SEQ ID NO: 1, HCDR2 as shown in SEQ ID NO: 2 and HCDR3 as shown in SEQ ID NO: 3.

In some embodiments, the targeting moiety It comprises HCDR1 as shown in SEQ ID NO:4, HCDR2 as shown in SEQ ID NO:5 and HCDR3 as shown in SEQ ID NO:6.

In some embodiments, the targeting moiety It comprises HCDR1 as shown in SEQ ID NO:7, HCDR2 as shown in SEQ ID NO:8 and HCDR3 as shown in SEQ ID NO:9.

In some embodiments, the targeting moiety It comprises HCDR1 as shown in SEQ ID NO: 23, HCDR2 as shown in SEQ ID NO: 24 and HCDR3 as shown in SEQ ID NO: 25.

In some embodiments, the targeting moiety comprising the amino acid sequence as shown in SEQ ID NO: 10 or SEQ ID NO: 11, or comprising the amino acid sequence as shown in positions 1 to 127 of SEQ ID NO: 12, or comprising the amino acid sequence as shown in positions 1 to 115 of SEQ ID NO: 22. In other embodiments, the targeting moiety comprising an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence set forth in SEQ ID NO: 10 or SEQ ID NO: 11. In yet other embodiments, the targeting moiety comprising an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identical to the amino acid sequence shown at positions 1 to 127 of SEQ ID NO: 12. In other embodiments, the targeting moiety comprising an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identical to the amino acid sequence shown at positions 1 to 115 of SEQ ID NO: 22.

In some embodiments, the targeting moiety comprising the amino acid sequence shown in SEQ ID NO: 10. In some embodiments, the targeting moiety comprising the amino acid sequence shown in SEQ ID NO: 11. In some embodiments, the targeting moiety comprising the amino acid sequence shown at positions 1 to 127 of SEQ ID NO: 12. In other embodiments, the targeting moiety It comprises the amino acid sequence shown at positions 1 to 115 in SEQ ID NO: 22.

In some embodiments, the modified targeting moiety comprising the amino acid sequence shown in SEQ ID NO: 12. In some embodiments, when the targeting moiety When linked to Gly in formula (I), its C-terminal amino acid sequence GGHHHHHH (SEQ ID NO: 19) is removed by the Sortase enzyme. In some embodiments, the modified targeting moiety It comprises the amino acid sequence shown at positions 1 to 133 in SEQ ID NO: 12.

In some embodiments, the modified targeting moiety comprising the amino acid sequence shown in SEQ ID NO: 13. In some embodiments, when the targeting moiety When linked to Gly in formula (I) or (II), its C-terminal amino acid sequence GG is removed by the Sortase enzyme. In some embodiments, the modified targeting moiety It comprises the amino acid sequence shown at positions 1 to 141 in SEQ ID NO: 13.

In some embodiments, the modified targeting moiety comprising the amino acid sequence shown in SEQ ID NO: 22. In some embodiments, when the targeting moiety When linked to Gly in formula (I) or (II), its C-terminal amino acid sequence GGHHHHHH (SEQ ID NO: 19) is removed by the Sortase enzyme. In some embodiments, the modified targeting moiety It comprises the amino acid sequence shown at positions 1 to 121 in SEQ ID NO: 22.

In some embodiments, each _La is independently selected from the following structures:

-(Gly) _n -, wherein n is an integer selected from 2 to 20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, preferably an integer from 2 to 10, more preferably 3;

-NH-C _1-10 alkylene-(CO)-, preferably -NH-(CH ₂ ) ₄ -(CO)-;

C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -(CO)-, C _2-6 alkynyl, C _6-10 arylene, 6-10 membered heteroarylene; preferably, L _a is each independently The wavy line with * indicates the target part The wavy line indicates the site of attachment to G of the cargo unit; and

C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -(CO)- and 3-10 membered heterocycloalkylene; preferably, L _a is each independently The wavy line with * indicates the target part The wavy line indicates the site of attachment to G of the cargo unit.

In some specific embodiments, each _La is independently selected from the following structures:

-(Gly) ₃ -, -NH-(CH ₂ ) ₄ -(CO)-, The wavy line with * indicates the target part The wavy line indicates the site of attachment to G of the cargo unit.

In some embodiments, G is each independently selected from the combination of 3) and 4) below:

3) one or more natural amino acids or unnatural amino acids or oligomeric natural or unnatural amino acids having a degree of polymerization of 2-20; 4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl.

In some specific embodiments, each G is independently selected from the following structures:

wherein g is an integer selected from 1-20, preferably an integer from 1-5;

Preferably,

wherein g is an integer selected from 1-20, preferably an integer from 1-5;

More preferably,

Further preferably,

Among them, the wavy line with * indicates the site connected to L _a , the wavy line with # indicates the site connected to L _c or L _b , and the wavy line indicates the site connected to L _b or L _c .

In some embodiments, ^G1 and ^G3 are each independently selected from a chemical bond or the following structure:

In some preferred embodiments, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,

The end of the wavy line with * is close to one end.

In some more preferred embodiments, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,

The end of the wavy line with * is close to one end.

In some embodiments, PEG is -( _CH2CH2O ) _x- or _- ( _OCH2CH2 ) _y- , where x or y is an integer of 1-10, preferably an integer of 2-6, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or ₁₀ .

In some embodiments, L _b is each independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, and C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl.

In some specific embodiments, _Lb are each independently selected from a chemical bond,

The wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some embodiments, L _c is a chemical bond. In other embodiments, L _c is Among them, the wavy line with * indicates the site connected to Q, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some embodiments, Q is a small molecule binder. In other embodiments, Q is independently selected from the following structures:

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy.

In some specific embodiments, Q is independently selected from

In some embodiments, D is a chelating group for a radionuclide. In other embodiments, D is independently selected from

Bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl-(hydroxy)amino]- 4-oxobutyryl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo, [6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4 ,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane- 4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3 (1-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7- triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneamine tetraacetic acid (TMT), 1,4,7-triazacyclononane-1 ,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid and triethylenetetraaminehexaacetic acid (TTHA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide.

In some specific embodiments, each D is independently selected from 1,4,7,10-tetraazacyclododecane-N,N',N",N'"-tetraacetic acid, 1,4,7-triazacyclononanetriacetic acid (NOTA), and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide.

In some embodiments, the radionuclide is selected from any one of the radioactive cations or anions of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At, and Er. Preferably, the radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴¹ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; more preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu.

In some embodiments, j is an integer selected from 1-10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. In other embodiments, k is an integer selected from 1-10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. In still other embodiments, o is an integer greater than 0 and less than 10 or a non-integer.

In some embodiments, Formula (I) is selected from the following structures:

Preferably,

Preferably,

More preferably,

Among them, -S- and -GA-LPET- in the above structure are contained in the targeting part Part of the amino acids in.

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, _Lb is a chemical bond, _Lc is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 2, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is

L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In another embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, _Lb is a chemical bond, _Lc is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is

L _c is a chemical bond, G is D is N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is

L _c is a chemical bond, G is D is 1,4,7-triazacyclononane triacetic acid (NOTA), Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -NH-( _CH2 ) _4- (CO)-, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

Wherein, Q represents the target moiety of glutamine).

In a specific embodiment, j is 1, k is 1, o is 1, and _La is L _b is

L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

Wherein, s represents the target part The sulfur atom in the cysteine (or

In a specific embodiment, j is 1, k is 1, o is 1, and _La is L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

Wherein, s represents the target part The sulfur atom in the cysteine (or

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, _Lb is a chemical bond, _Lc is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

In a specific embodiment, j is 1, k is 1, o is 1, _La is -(Gly) ₃ -, and _Lb is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is

In a specific embodiment, the compound of formula (I) has the following structure:

The present invention also relates to a conjugate comprising a structure of formula (I'):

in,

Q is the albumin binding unit;

D and D' are each independently a chelating group for a radionuclide;

A is a targeting moiety, which comprises an antibody or an antigen-binding fragment thereof; preferably, the antibody is a single domain antibody or a single chain antibody;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

Each of L ₁ , L ₂ , L _1′ and L _2′ is independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl;

m is an integer selected from 0-20;

n is an integer selected from 2 to 20;

z is an integer selected from 1-20.

The present invention can use ligase-dependent conjugation (LDC) technology to couple A with the rest of the compound of formula (I). Here, the ligase refers to a transpeptidase, including but not limited to various natural sortase enzymes (including A, B, C, D, and L. plantarum sortase, etc., see patents US20110321183A and WO2022160156A for details) and various novel transpeptidases that have been optimized and modified. The coupling reaction is achieved by means of biological enzyme catalysis, and the reaction conditions are mild, which reduces the physical and chemical damage to the antibody during the coupling process. The preparation process and process are more optimized, easy to industrialize and upgrade, and conducive to the quality control of the coupled product.

In some embodiments, the A terminus is modified and coupled to the (Gly) _n portion of formula (I) under the action of a ligase.

In some embodiments, the ligase is a Sortase enzyme. In some embodiments, A comprises a C-terminally modified or N-terminally modified antibody. In some embodiments, the antibody, spacer (SP), and ligase donor substrate recognition sequence are sequentially connected. In some embodiments, the antibody and ligase donor substrate recognition sequence are sequentially connected.

In some embodiments, the spacer is selected from GA, GGGGS, GGGGSGGGGS, or GGGGSGGGGSGGGGS; preferably, the spacer is GA.

In some embodiments, the ligase donor substrate recognition sequence is LPX ₁ TGX ₂ (SEQ ID NO: 17), wherein X ₁ is any natural or unnatural amino acid, and X ₂ is absent or is an amino acid fragment comprising 1-10 amino acids. In particular, the ligase donor substrate recognition sequence is LPETGG (SEQ ID NO: 18).

In some embodiments, Antibody A is an anti-prostate-specific membrane antigen (PSMA) antibody; preferably, Antibody A is an anti-PSMA single domain antibody. In other embodiments, Antibody A is an anti-epidermal growth factor receptor 2 (HER2) antibody. In yet other embodiments, Antibody A is an anti-Delta-like ligand 3 (DLL3) antibody.

In some embodiments, antibody A comprises HCDR1 as shown in SEQ ID NO:1, HCDR2 as shown in SEQ ID NO:2, and HCDR3 as shown in SEQ ID NO:3.

In some embodiments, antibody A comprises HCDR1 as shown in SEQ ID NO:4, HCDR2 as shown in SEQ ID NO:5 and HCDR3 as shown in SEQ ID NO:6.

In some embodiments, antibody A comprises HCDR1 as shown in SEQ ID NO:7, HCDR2 as shown in SEQ ID NO:8 and HCDR3 as shown in SEQ ID NO:9.

In some embodiments, antibody A comprises HCDR1 as shown in SEQ ID NO:23, HCDR2 as shown in SEQ ID NO:24 and HCDR3 as shown in SEQ ID NO:25.

In some embodiments, antibody A comprises the amino acid sequence set forth in SEQ ID NO: 10 or SEQ ID NO: 11, or comprises the amino acid sequence set forth in positions 1 to 127 of SEQ ID NO: 12, or comprises the amino acid sequence set forth in positions 1 to 115 of SEQ ID NO: 22. In some embodiments, antibody A comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence set forth in SEQ ID NO: 10 or SEQ ID NO: 11. In some embodiments, antibody A comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence set forth in positions 1 to 127 of SEQ ID NO: 12. In some embodiments, antibody A comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence set forth in SEQ ID NO: 22 at positions 1 to 115. In some embodiments, antibody A comprises the amino acid sequence set forth in SEQ ID NO: 10. In some embodiments, antibody A comprises the amino acid sequence set forth in SEQ ID NO: 11. In some embodiments, antibody A comprises the amino acid sequence set forth in SEQ ID NO: 12 at positions 1 to 127. In some embodiments, antibody A comprises the amino acid sequence set forth in SEQ ID NO: 22 at positions 1 to 115.

In some embodiments, the modified antibody A comprises the amino acid sequence as shown in SEQ ID NO: 12. In some embodiments, when antibody A is linked to Gly in formula (I'), its C-terminal amino acid sequence GGHHHHHH (SEQ ID NO: 19) is removed by the Sortase enzyme. In some embodiments, the modified antibody A comprises the amino acid sequence as shown in positions 1 to 133 of SEQ ID NO: 12.

In some embodiments, the modified antibody A comprises the amino acid sequence as shown in SEQ ID NO: 13. In some embodiments, when antibody A is linked to Gly in formula (I'), its C-terminal amino acid sequence GG is removed by the Sortase enzyme. In some embodiments, the modified antibody A comprises the amino acid sequence as shown in positions 1 to 141 of SEQ ID NO: 13.

In some embodiments, the modified antibody A comprises the amino acid sequence as shown in SEQ ID NO: 22. In some embodiments, when antibody A is linked to Gly in formula (I'), its C-terminal amino acid sequence GGHHHHHH (SEQ ID NO: 19) is removed by the Sortase enzyme. In some embodiments, the modified antibody A comprises the amino acid sequence as shown in positions 1 to 121 of SEQ ID NO: 22.

In some embodiments, Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)-, or -NH-(PEG) _i -(CO)-, wherein the (PEG) _i comprises 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and optionally, a C 1-10 alkylene is attached to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. In some embodiments, i 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, Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and optionally a C _1-10 alkylene group is connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit; preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; more preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-, -NH-PEG ₃ -C ₂ H ₄ -(CO)- or -NH-PEG ₄ -C ₃ H ₆ -(CO)-; further preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. In some embodiments, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, wherein i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. In some embodiments, Ld is -NH-(PEG) _i -(CO)-, wherein i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. In some embodiments, Ld is -NH-PEG ₄ -(CO)-.

In some embodiments, _L1 and L1 _' are each independently selected from any one of a chemical bond, a _C1-10 alkylene group, -NH-, and -(CO)-, or any combination thereof; preferably, _L1 is selected from -( _CH2 ) _4- NH-, -CO-NH- _{C2H4 -NH-} , or -NH-, and L1 _' is selected from a chemical bond, -( _CH2 ) _4- NH-, -CO-NH- _{C2H4 -} NH-, or -NH-. In some embodiments, _L1 and L1 _' are the same. In some embodiments, _L2 and L2 _' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a _C1-10 alkylene group, and -NH-, or any combination thereof; preferably, _L2 is selected from -(CO)-, -( _CH2 ) _4- NH-, -CO-an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-, and L2 _' is selected from a chemical bond, -(CO)-, -( _CH2 ) ₄ -NH-, -CO-an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-. In some embodiments, _L2 and L2 _' are the same.

In some embodiments, m is an integer selected from 0-10; preferably, m is 0, 1 or 2; more preferably, m is 0 or 1. In some embodiments, n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3. In some embodiments, z is an integer selected from 1-10, preferably, z is 1, 2, 3 or 4; more preferably, z is 1.

In some embodiments, D and D' are each independently selected from bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl] -(hydroxy)amino]-4-oxobutanoyl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4,7,1 0-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine -N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane-4,7,10-triacetate (HP-DOA3), 6-hydrazino-N- Methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridinone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7-triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecaproic acid (4,7-diacetic acid), ... alkane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneaminetetraacetic acid) (TMT), 1,4,7-triazacyclononane-1,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (T Preferably, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid; D' is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid.

In some embodiments, the radionuclide is selected from any one of the radioactive cations or anions of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At, and Er. Preferably, the radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu.

In some embodiments, Q is selected from

The wavy line indicates the site of binding to _L2 in formula (I');

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, halogen is fluorine, chlorine, bromine or iodine; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; preferably, halogen is fluorine, chlorine, bromine or iodine; preferably, Q is selected from

In some embodiments, m is 0, and the conjugate of formula (I') has the structure shown in formula (I"):

wherein each group is as defined in formula (I') of the present invention.

In a specific embodiment, m is 0, n is 3, z is 1, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -(CH ₂ ) ₄ -NH-, L ₂ is -(CO)-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (I') has the following structure:

In a specific embodiment, m is 1, n is 3, z is 1, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ and L _1' are -(CH ₂ ) ₄ -NH-, L ₂ and L _2' are -(CO)-, D and D' are 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (I') has the following structure:

In a specific embodiment, m is 0, n is 3, z is 1, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (I') has the following structure:

In a specific embodiment, m is 0, n is 3, z is 1, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (I') has the following structure:

Another aspect of the present invention provides a compound comprising the following structure:

in,

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

L _a' is selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20.

In another aspect, the present invention also provides a compound comprising the following structure:

in,

Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each L _a' is independently selected from the following 1), 2) or a combination thereof:

1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, and k2 are each independently an integer of 0-10.

In some embodiments, L _a' is selected from the following structures:

(Gly) _n -, wherein n is an integer selected from 2 to 20, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, preferably an integer from 2 to 10, more preferably 3;

C _1-10 alkyl-(CO)-, wherein the alkyl is substituted with an amino substituent; preferably NH ₂ -(CH ₂ ) ₄ -(CO)-;

_C1-10 alkyl, wherein the carbon chain unit of the alkyl is optionally replaced by a substituent selected from -(CO)-, _C2-6 alkynyl and/or a 5-10 membered heteroarylene, wherein the heteroarylene is substituted by a sulfonyl- _C1-10 alkyl substituent; preferably wherein the wavy line indicates the site of attachment to G or ^G1 ; and

C _1-10 alkyl, wherein the carbon chain unit of the alkyl is optionally replaced by a -(CO)- substituent, and the alkyl is substituted by a 3-10 membered heterocycloalkyl; preferably The wavy line indicates the site of attachment to G or ^G1 ;

_C1-10 alkyl, wherein the carbon chain unit of the alkyl is optionally replaced by at least one substituent selected from -(CO)-, and the alkyl is substituted by at least one amino group; preferably The wavy line indicates the site of attachment to G or ^G1 .

In some specific embodiments, L _a' is selected from the following structures:

(Gly) ₃ -, NH ₂ -(CH ₂ ) ₄ -(CO)-, The wavy line indicates the site of attachment to G or ^G1 .

In some embodiments, G is selected from the combination of 3) and 4) below:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids having a degree of polymerization of 2-20; 4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl.

In some specific embodiments, G is selected from the following structures:

wherein g is an integer selected from 1-20, preferably an integer from 1-5;

Preferably,

wherein g is an integer selected from 1-20, preferably an integer from 1-5;

More preferably,

Further preferably,

Among them, the wavy line with * indicates the site connected to L _a' , the wavy line with # indicates the site connected to L _c , and the wavy line indicates the site connected to L _b .

In some embodiments, ^G1 and ^G3 are each independently selected from a chemical bond or the following structure:

In some embodiments, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,

The end of the wavy line with * is the end closer to L _a' .

In some embodiments, when n2 is 0, ^G2 and ^G3 are absent, and ^G4 is selected from the following structural fragments,

The wavy line with * indicates the site of connection with ^G1 .

In other embodiments, when n2 is not 0, ^G2 and ^G4 are both the following structural fragments,

The wavy line with * indicates the site connected to ^G1 or ^G3 .

In some embodiments, L _b is each independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, and C _6-10 arylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl group.

In some specific embodiments, _Lb are each independently selected from a chemical bond, The wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some embodiments, L _c is a chemical bond. In other embodiments, L _c is Among them, the wavy line with * indicates the site connected to Q, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some embodiments, Q is a small molecule binder. In other embodiments, Q is independently selected from the following structures:

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy.

In some specific embodiments, Q is independently selected from

In some embodiments, each D is independently selected from

Bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl-(hydroxy)amino]- 4-oxobutyryl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo, [6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4 ,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane- 4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3 (1-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7- triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneamine tetraacetic acid (TMT), 1,4,7-triazacyclononane-1 ,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid and triethylenetetraaminehexaacetic acid (TTHA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide.

In some specific embodiments, each D is independently selected from 1,4,7,10-tetraazacyclododecane-N,N',N",N'"-tetraacetic acid, 1,4,7-triazacyclononanetriacetic acid (NOTA), and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide.

In some embodiments, the radionuclide is selected from any one of the radioactive cations or anions of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At, and Er. Preferably, the radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; more preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu.

In some embodiments, the compound of formula (III) has the following structure:

Preferably,

Preferably,

More preferably,

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, L _b is a chemical bond, L _c is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 2, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In another embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, L _b is a chemical bond, L _c is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7-triazacyclononane triacetic acid (NOTA), Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is NH ₂ -(CH ₂ ) ₄ -(CO)-, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, and L _a' is L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, and L _a' is L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, L _b is a chemical bond, L _c is a chemical bond, and G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

In a specific embodiment, j is 1, k is 1, L _a' is (Gly) ₃ -, and L _b is L _c is a chemical bond, G is D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, Q is In a specific embodiment, the compound of formula (III) has the following structure:

Another aspect of the present invention provides a compound comprising the following structure:

in,

Q is the albumin binding unit;

D and D' are each independently a chelating group for a radionuclide;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by a substituent selected from -O-, -NH- and -(CO)-;

L ₁ , L ₂ , each of L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and C _1-10 alkyl;

m is an integer selected from 0-20;

n is an integer selected from 2-20.

In some embodiments, Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)-, or -NH-(PEG) _i -(CO)-, wherein the (PEG) _i comprises 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and optionally, a C 1-10 alkylene is attached to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. In some embodiments, i 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, Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and optionally a C _1-10 alkylene group is connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit; preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; more preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-, -NH-PEG ₃ -C ₂ H ₄ -(CO)- or -NH-PEG ₄ -C ₃ H ₆ -(CO)-; further preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. In some embodiments, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, wherein i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. In some embodiments, Ld is -NH-PEG ₄ -(CO)-.

In some embodiments, _L1 and L1 _' are each independently selected from any one of a chemical bond, a _C1-10 alkylene group, -NH-, and -(CO)-, or any combination thereof; preferably, _L1 is selected from -( _CH2 ) _4- NH-, -CO-NH- _{C2H4 -NH-} , or -NH-, and L1 _' is selected from a chemical bond, -( _CH2 ) _4- NH-, -CO-NH- _{C2H4 -} NH-, or -NH-. In some embodiments, _L1 and L1 _' are the same.

In some embodiments, _L2 and L2 _' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a _C1-10 alkylene group, and -NH-, or any combination thereof; preferably, _L2 is selected from -(CO)-, -( _CH2 ) _4- NH-, -CO-an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-, and L2 _' is selected from a chemical bond, -(CO)-, -( _CH2 ) ₄ -NH-, -CO-an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-. In some embodiments, _L1 and L1 _' are the same.

In some embodiments, m is an integer selected from 0-10; preferably, m is 0, 1 or 2; more preferably, m is 0 or 1. In some embodiments, n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3.

In some embodiments, D and D' are each independently selected from bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl] -(hydroxy)amino]-4-oxobutanoyl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4,7,1 0-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine -N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane-4,7,10-triacetate (HP-DOA3), 6-hydrazino-N- Methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridinone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7-triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecaproic acid (4,7-diacetic acid), ... alkane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneaminetetraacetic acid) (TMT), 1,4,7-triazacyclononane-1,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (T Preferably, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid; D' is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid.

In some embodiments, the radionuclide is selected from any one of the radioactive cations or anions of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At, and Er; preferably, the radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ^{212 Bi} , ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu.

In some embodiments, Q is selected from

The wavy line indicates the binding site to L ₂ in formula (II');

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, halogen is fluorine, chlorine, bromine or iodine; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; preferably, halogen is fluorine, chlorine, bromine or iodine;

Preferably, Q is selected from

In some embodiments, Formula (II') is selected from the following structures:

Preferably,

In some embodiments, m is 0, and the compound of formula (II') has the structure shown in formula (II"):

wherein each group is as defined in formula (II') of the present invention.

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -(CH ₂ ) ₄ -NH-, L ₂ is -(CO)-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 1, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ and L _1' are -(CH ₂ ) ₄ -NH-, L ₂ and L _2' are -(CO)-, D and D' are 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In another aspect, the present invention further provides a conjugate comprising the following structure of formula (III):

in,

Ab is a targeting moiety, which comprises an antibody or an antigen-binding fragment thereof; preferably, the antibody is a single domain antibody or a single chain antibody;

Gly is a glycine residue; -(PEG) _i - is optionally present between the carboxyl group of any one glycine and the amino group of another glycine, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and a C _1-10 alkylene group is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the alkylene group is optionally replaced by a substituent selected from -O-, -NH- and -(CO)-;

Each X ₁ is independently lysine (Lys), and the X ₁ is further connected to D;

Each X ₂ is independently Lys, and said X ₂ is further connected to D' and Q;

Each of D and D' is independently a chelating group for a radionuclide;

Each Q is independently an albumin binding unit;

m is an integer selected from 0-20;

n is an integer selected from 2 to 20;

z is an integer selected from 1-20.

In some embodiments, Gly in formula (III") of the present invention has the following structure:

Wherein, * indicates the site of connection with Ab, represents the site of attachment to _X1 or Ld.

In some embodiments, Ld is a chemical bond.

In some embodiments, Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and optionally a C _1-10 alkylene group is connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit; preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; more preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-, -NH-PEG ₃ -C ₂ H ₄ -(CO)- or -NH-PEG ₄ -C ₃ H ₆ -(CO)-; further preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. In some embodiments, i 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, the end of Ab is modified and coupled to -(Gly) _n - in formula (III") under the action of a ligase.

In some embodiments, the ligase is a Sortase enzyme. In some embodiments, the Ab comprises a C-terminally modified or N-terminally modified antibody. In some embodiments, the antibody, spacer (SP), and ligase donor substrate recognition sequence are sequentially connected. In some embodiments, the antibody and ligase donor substrate recognition sequence are sequentially connected.

In some embodiments, the spacer is selected from GA, GGGGS, GGGGSGGGGS or GGGGSGGGGSGGGGS; preferably, the spacer is GA. In particular, the ligase donor substrate recognition sequence is LPETGG.

In some embodiments, the ligase donor substrate recognition sequence is LPX ₁ TGX ₂ , wherein X ₁ is any natural or unnatural amino acid, and X ₂ does not exist or is an amino acid fragment comprising 1-10 amino acids.

In some embodiments, the Ab is an anti-prostate specific membrane antigen (PSMA) antibody; preferably, the Ab is an anti-PSMA single domain antibody. In some embodiments, the Ab is an anti-epidermal growth factor receptor 2 (HER2) antibody. In yet other embodiments, the Ab is an anti-Delta-like ligand 3 (DLL3) antibody.

In some embodiments, the antibody Ab comprises HCDR1 as shown in SEQ ID NO:1, HCDR2 as shown in SEQ ID NO:2, and HCDR3 as shown in SEQ ID NO:3.

In some embodiments, the antibody Ab comprises HCDR1 as shown in SEQ ID NO:4, HCDR2 as shown in SEQ ID NO:5, and HCDR3 as shown in SEQ ID NO:6.

In some embodiments, the antibody Ab comprises HCDR1 as shown in SEQ ID NO:7, HCDR2 as shown in SEQ ID NO:8, and HCDR3 as shown in SEQ ID NO:9.

In some embodiments, the antibody Ab comprises HCDR1 as shown in SEQ ID NO:23, HCDR2 as shown in SEQ ID NO:24, and HCDR3 as shown in SEQ ID NO:25.

In some embodiments, the antibody Ab comprises the amino acid sequence as set forth in SEQ ID NO: 10 or SEQ ID NO: 11, or comprises the amino acid sequence as set forth in positions 1 to 127 of SEQ ID NO: 12, or comprises the amino acid sequence as set forth in positions 1 to 115 of SEQ ID NO: 22. In some embodiments, the antibody Ab comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence as set forth in SEQ ID NO: 10 or SEQ ID NO: 11. In some embodiments, the antibody Ab comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to the amino acid sequence as set forth in positions 1 to 127 of SEQ ID NO: 12. In other embodiments, antibody Ab comprises an amino acid sequence that is at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% identical to the amino acid sequence shown at positions 1 to 115 of SEQ ID NO:22.

In some embodiments, the antibody Ab comprises the amino acid sequence set forth in SEQ ID NO: 10. In some embodiments, the antibody Ab comprises the amino acid sequence set forth in SEQ ID NO: 11. In some embodiments, the antibody Ab comprises the amino acid sequence set forth in positions 1 to 127 of SEQ ID NO: 12. In other embodiments, the antibody Ab comprises the amino acid sequence set forth in positions 1 to 115 of SEQ ID NO: 22.

In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown in SEQ ID NO: 12. In some embodiments, when the antibody Ab is linked to Gly in formula (III"), its C-terminal amino acid sequence GGHHHHHH is removed by the Sortase enzyme. In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown at positions 1 to 133 in SEQ ID NO: 12.

In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown in SEQ ID NO: 13. In some embodiments, when the antibody Ab is linked to Gly in formula (III"), its C-terminal amino acid sequence GG is removed by the Sortase enzyme. In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown in positions 1 to 141 in SEQ ID NO: 13.

In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown in SEQ ID NO:22. In some embodiments, when the modified antibody Ab is linked to Gly in formula (III"), its C-terminal amino acid sequence GGHHHHHH (SEQ ID NO:19) is removed by Sortase enzyme. In some embodiments, the modified antibody Ab comprises the amino acid sequence as shown at positions 1 to 121 in SEQ ID NO:22.

In some embodiments, X ₁ has the following structure:

wherein D is as defined in formula (II') of the present invention.

In some embodiments, X ₂ has the following structure:

in,

D', _L2 and Q are as defined in formula (II') of the present invention.

In some embodiments, X ₂ has the following structure:

in,

D', _L1 and Q are as defined in formula ( _II ') of the present invention. In some embodiments, _L1 is _-NHCH2CH2NH- .

In some embodiments, in formula (III") of the present invention, m is 0, z is 1, Ld is -NH-(C ₂ H ₄ -O) _i -C ₂ H ₄ -(CO)-, and X ₂ is formula (IV-1), which has the following structure of formula (V-1):

in,

Ab is as defined in formula (III") of the present invention;

i, D _' , _L2 and Q are as defined in formula (II') of the present invention. In some embodiments, _L2 is _-NHCH2CH2NH- .

In some embodiments, in formula (III") of the present invention, m is 0, z is 1, Ld is -NH-(C ₂ H ₄ -O) _i -C ₂ H ₄ -(CO)-, and X ₂ is formula (IV-2), which has the following structure of formula (V-2):

in,

Ab is as defined in formula (III") of the present invention;

i, D', _L1 and Q are as defined in formula (II') of the present invention.

In another aspect, the present invention provides a compound having the following formula (III'):

in,

X ₁ , X ₂ , Ld, n and z are as defined in formula (III") of the present invention.

In another aspect, the present invention relates to a radionuclide conjugate comprising a radionuclide conjugate represented by formula (I), (I'), (I"), (II) or (III") and a radionuclide.

Targeting moiety ( A or Ab)

In the conjugate of the present invention, A is a targeting moiety that targets a specific target. By including a targeting moiety in the conjugate of the present invention, excellent cell/tissue targeting function can be achieved. "Targeting moiety" refers to having affinity for a specific target (e.g., receptor, cell surface protein, cytokine, tumor-specific antigen, etc.). The targeting molecule can deliver the payload to a specific site in the body through targeted delivery. The targeting moiety can recognize one or more targets. The specific target is defined by the target it recognizes. For example, a receptor-targeting targeting moiety can deliver the portion of the chelated radionuclide to a site containing a large number of receptors.

In some embodiments, A is a targeting moiety that targets prostate-specific membrane antigen (PSMA). PSMA is expressed on malignant cancer cells. As used herein, the term "cancer" refers to a neoplasm characterized by uncontrolled, often rapidly proliferating cells that tend to invade surrounding tissues and metastasize to distant body sites; this includes both benign and malignant neoplasms. Malignant tumors of cancer are often characterized by anaplasia, invasion, and metastasis; whereas benign malignant tumors generally do not possess these characteristics. Specifically, PSMA may optionally be highly expressed in prostate cancer cells, pancreatic cancer cells, renal cancer cells, or bladder cancer cells. The presence of cells or tissues expressing PSMA can be indicative of a prostate tumor (cell), a metastatic prostate tumor (cell), a renal tumor (cell), a pancreatic tumor (cell), a bladder tumor (cell), and combinations thereof. Therefore, the radionuclide conjugates, pharmaceutical compositions, and kits of the present invention can be used to diagnose and, optionally, delay or treat prostate cancer, renal cancer, pancreatic cancer, or bladder cancer. In other embodiments, A is a targeting moiety that targets epidermal growth factor receptor 2 (HER2). In yet other embodiments, A is a targeting moiety that targets Delta-like ligand 3 (DLL3).

In one embodiment, A is a targeting moiety comprising an antibody or an antigen-binding fragment thereof, wherein the antibody is a single domain antibody.

Linker Compounds and Linker Compound Fragments

In addition to the targeting moiety (A), the conjugate of the present invention also comprises a loading unit having the structure of formula (III):

in,

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

L _a' is selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, a C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, the arylene group, and the heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof:

3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20.

In some embodiments, in addition to the targeting moiety (A), the conjugate of the present invention further comprises a cargo-linker moiety (LP) having the structure of formula (II'):

in,

Q is the albumin binding unit;

D and D' are each independently a chelating group for a radionuclide;

A is a targeting moiety, which comprises an antibody or an antigen-binding fragment thereof; preferably, the antibody is a single domain antibody or a single chain antibody;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

Each of L ₁ , L ₂ , L _1′ and L _2′ is independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl;

m is an integer selected from 0-20;

n is an integer selected from 2-20.

In some embodiments, the radionuclide conjugate of the present invention further comprises a compound fragment of formula (V):

in,

Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, a C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, the arylene group, and the heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, wherein G is selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkyl group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30; preferably an integer from 1-10; more preferably an integer from 1-5;

k is an integer selected from 1-20; preferably an integer of 1-10; more preferably an integer of 1-5.

In some embodiments, the albumin binding unit is a small molecule.

In some embodiments, the radioconjugate of the present invention further comprises a compound fragment of formula (VI):

in,

Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, a C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, the arylene group, and the heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer of 0-10; preferably an integer of 0-5; for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10;

j1, j2, k1, k2 are each independently an integer of 0-10, preferably an integer of 0-5, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

In some embodiments, the albumin binding unit is a small molecule.

In some embodiments, the chelating group and albumin binding unit are as defined herein.

In some embodiments, G is selected from the following structures:

wherein g is an integer selected from 1-20; preferably an integer from 1-5; for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20;

Preferably,

wherein g is an integer selected from 1-20; preferably an integer from 1-5; for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20;

More preferably,

Further preferably,

Among them, the wavy line with # indicates the site connected to L _c or L _b , and the wavy line indicates the site connected to L _b or L _c .

In some embodiments, ^G1 and ^G3 are each independently selected from a chemical bond or the following structure:

In some embodiments, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,

The end of the wavy line with * is the end closer to ^G1 or ^G3 .

In some embodiments, when n2 is 0, ^G2 and ^G3 are absent, and ^G4 is selected from the following structural fragments:

In other embodiments, when n2 is not 0, ^G2 and ^G4 are both the following structural fragments:

The wavy line with * indicates the site connected to ^G1 or ^G3 .

In some specific embodiments, each L _b is independently selected from the following structures:

Chemical bonds;

Among them, the wavy line with * indicates the site of connection with the chelating group, and the wavy line indicates the site of connection with G, ^G2 , or ^G4 ;

Wherein, the wavy line with * indicates the site of connection with the chelating group, and the wavy line indicates the site of connection with G, ^G2 or ^G4 ; or

The wavy line with * indicates the site connected to the chelating group, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some specific embodiments, L _c is a chemical bond; or

The wavy line with * indicates the site connected to the albumin binding unit, and the wavy line indicates the site connected to G, ^G2 , or ^G4 .

In some embodiments, the radionuclide conjugate of the present invention is a compound fragment of formula (III'):

in,

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

L ₁ , L ₂ , each L _1′ and L _2′ are each independently covalently linked to a chelating group or an albumin-binding unit; wherein L ₁ , L ₂ , each L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl;

m is an integer selected from 0-20.

In some embodiments, Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)-, and -NH-(PEG) _i -(CO)-, wherein the (PEG) _i comprises 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and optionally, a C _1-10 alkylene group is attached to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. In some embodiments, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, and i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5, or 6; more preferably, i is 4.

In some specific embodiments, Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and optionally, a C _1-10 alkylene group is connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. In some preferred embodiments, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-. In a more preferred embodiment, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-. In a further preferred embodiment, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-.

In some embodiments, L ₁ and L _1′ are each independently covalently linked to a chelating group, and L ₂ and L _2′ are each independently covalently linked to an albumin-binding unit. In some embodiments, the albumin-binding unit is a small molecule.

In some embodiments, L ₁ and L _1' are each independently selected from any one of a chemical bond, a C _1-10 alkylene group, -NH-, and -(CO)-, or any combination thereof. In some preferred embodiments, L ₁ is selected from -(CH ₂ ) ₄ -NH-, -CO-NH-C ₂ H ₄ -NH-, or -NH-. In other preferred embodiments, L _1' is selected from a chemical bond, -(CH ₂ ) ₄ -NH-, -CO-NH-C ₂ H ₄ -NH-, or -NH-.

In some embodiments, _L2 and L2 _' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a _C1-10 alkylene group, and -NH-, or any combination thereof. In some preferred embodiments, _L2 is selected from -(CO)-, -( _CH2 ) ₄ -NH-, or -CO- an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-; preferably, _L2 is -CO-Lys-. In other preferred embodiments, L2 _' is selected from a chemical bond, -(CO)-, -( _CH2 ) ₄ -NH-, or -CO- an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-; preferably, L2 _' is -CO-Lys-.

In some embodiments, m is an integer selected from 0-10; preferably, m is 0, 1 or 2; more preferably, m is 0 or 1. In some embodiments, n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3.

In some embodiments, the radionuclide conjugates of the present invention comprise a compound fragment of the structure of formula (VII):

in,

Ld' is selected from C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

^RA and ^RB are each independently optionally covalently linked to a chelating group and/or an albumin binding unit; wherein ^RA and ^RB are each independently selected from hydrogen or one or a combination of the following groups: _C1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and _C1-10 alkyl; wherein ^RA and ^RB are not simultaneously hydrogen;

^RC is optionally covalently linked to a chelating group, an albumin binding unit, or a combination thereof; wherein ^RC is selected from one or a combination of the following: a hydroxyl group, a natural or non-natural amino acid fragment, and a C _1-30 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NR ⁴ -, -(CO)-, -(C=S)-, and a C _6-10 arylene group, and the alkyl and arylene groups are optionally substituted by at least one substituent selected from the group consisting of hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

Said ^R4 is selected from hydrogen or _C1-10 alkyl, wherein the carbon chain unit of said alkyl is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, and said alkyl is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amino and sulfonyl- _C1-10 alkyl.

In some embodiments, the albumin binding unit is a small molecule.

In some embodiments, Ld' is selected from -(PEG) _i- and _C1-10 alkylene, wherein ( _PEG ) _i is 1-10 consecutive -( _OC2H4 )- or -( _{C2H4 -} O)- structural units, and optionally a _C1-10 alkylene is attached to at least one end of _the -( _OC2H4 )- or -( _C2H4 - _O )- structural unit. In a preferred embodiment, Ld' is selected from -( _C2H4 -O) _{4 - C2H4- and C5} alkylene.

In some embodiments, ^RA and ^RB are each independently selected from hydrogen or _C1-10 alkylene, wherein the alkylene is substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and _C1-10 alkyl; wherein ^RA and ^RB are not both hydrogen.

In some preferred embodiments, ^RA and ^RB are each independently hydrogen and C _1-10 alkylene, wherein the alkylene is substituted with amino; wherein ^RA and ^RB are not both hydrogen. In some more preferred embodiments, ^RA and ^RB are each independently hydrogen and

In some embodiments, ^RC is selected from hydroxyl,

In some embodiments, Formula (VII) is selected from the following structures:

Preferably,

In some embodiments, the present invention further provides a radionuclide conjugate comprising a structure of formula (V'):

in,

Each Q is independently an albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 1), 2) or a combination thereof:

1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20;

2) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkyl group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

j is an integer selected from 1-30;

k is an integer selected from 1-20.

In some embodiments, the present invention also provides a radionuclide conjugate comprising a structure of formula (VI'):

in,

Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit;

Each D is independently a chelating group for a radionuclide;

Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group;

Each G ¹ or G ³ , when present, is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl;

Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups:

1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl;

n1 and n2 are each independently an integer from 0 to 10;

j1, j2, k1, and k2 are each independently an integer of 0-10.

In some embodiments, Formula (V') is selected from the following structures:

Preferably,

In some embodiments, the present invention also provides a radionuclide conjugate comprising a structure of formula (VII'):

in,

Ld' is selected from C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

Said RA ^' , RB ^' and RC ^' each independently optionally comprise a chelating group and/or an albumin binding unit;

RA ^' and ^RB' are each independently selected from hydrogen or one or a combination of the following groups: _C1-10 alkyl, -NH- and -(CO)-, wherein the alkyl group is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and _C1-10 alkyl; wherein RA ^' and RB ^' are not hydrogen at the same time;

RC ^' comprises one or a combination selected from the following: a hydroxyl group, a natural or non-natural amino acid fragment, and a _C1-30 alkyl group, wherein the carbon chain unit of the alkyl group is optionally replaced by at least one substituent selected from -O-, ^-NR4- , -(CO)-, -(C=S)-, and a _C6-10 arylene group, and the alkyl group and the arylene group are optionally substituted by at least one substituent selected from the group consisting of hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, and sulfonyl- _C1-10 alkyl;

Said ^R4 is selected from hydrogen or _C1-10 alkyl, wherein the carbon chain unit of said alkyl is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, and said alkyl is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amino and sulfonyl- _C1-10 alkyl.

In some embodiments, the present invention provides a radionuclide conjugate comprising the structure of formula (II'):

in,

Q is the albumin binding unit;

D and D' are each independently a chelating group for a radionuclide;

Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-;

L ₁ , L ₂ , each of L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and C _1-10 alkyl;

m is an integer selected from 0-20.

The pharmacological effects of radionuclide conjugates require an appropriate half-life and tumor retention time. For example, drugs using small molecules and peptides as targeting carriers have too rapid blood clearance, leading to excretion before they are fully accumulated in tumors. Insufficient tumor accumulation and a short tumor retention time can result in a short-lasting therapeutic effect. However, due to the large molecular size of monoclonal antibodies, radionuclide conjugates using monoclonal antibodies as targeting carriers have slow tissue and tumor penetration, which in turn affects their tumor accumulation. Furthermore, their prolonged exposure to the bloodstream and normal tissues can lead to increased hematotoxicity and off-target toxicity. Compared to existing technologies, the radionuclide conjugates of the present invention, through the combination of a suitable targeting moiety and an albumin-binding unit, achieve an appropriate blood circulation half-life, thereby increasing tumor accumulation and prolonging tumor retention. At the same dose or even lower, the radionuclide conjugates of the present invention exhibit higher antitumor activity without any significant toxicity, significantly broadening the potential therapeutic window for this class of RDC drugs. A variety of enzyme site-directed conjugation and chemical conjugation have further broadened the selection of therapeutic targets for RDC drugs.

Albumin binding unit (Q)

In the conjugate of the present invention, Q is an albumin binding unit, in particular, specifically binds to human serum albumin (HSA).

Human serum albumin (HSA) is an abundant protein in human plasma. As used herein, the term "human serum albumin" or "HSA" preferably refers to serum albumin encoded by the human ALB gene or a functional variant, isoform, fragment or derivative thereof.

Without wishing to be bound by a particular theory, it is believed that the albumin binding unit (Q) in the conjugates of the present invention can preferably extend the circulation half-life of the radioconjugate and affect its partitioning in the blood, improving delivery to target cells or tissues. Therefore, the presence of the albumin binding unit (Q) improves the pharmacokinetic properties of the radioconjugates of the present invention and preferably does not interfere with (reduce or eliminate) the desired functions of the chelating group and the targeting moiety. The albumin binding unit can generally bind to albumin (such as HSA) with a relatively high affinity, preferably non-covalently. For example, the albumin binding unit can preferably non-covalently bind to albumin with a binding affinity of less than about 100 μM, such as about 3-50 μM.

In one embodiment, the albumin binding unit may preferably include straight-chain and branched lipophilic groups, for example, may include 1-40 carbon atoms and a distal acidic group.

In some embodiments, Q is a small molecule binder to HSA. In other embodiments, Q is independently selected from the following structures:

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy;

Preferably, Q is selected from In some embodiments, Q is selected from The wavy line indicates the site of binding to L ₂ in formula (II);

in,

R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, halogen is fluorine, chlorine, bromine or iodine; preferably, R ¹ is selected from methyl or iodine;

R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; preferably, halogen is fluorine, chlorine, bromine or iodine.

In one embodiment, Q is selected from

Chelating groups for radionuclides (D and D’)

In the conjugates of the present invention, D and D' are each independently a chelating group for a radionuclide. In some embodiments, D and D' are the same.

The terms "chelating agent," "chelating group," or "chelating moiety" are used interchangeably herein to refer to a ligand capable of forming two or more coordination bonds with a central (metal) ion. Such one or more molecules that share an electron pair may also be referred to as a "Lewis base." The central (metal) ion is typically coordinated to the chelating agent through two or more electron pairs. Typically, the electron pairs of the chelating agent form coordination bonds with a single central (metal) ion; however, in some cases, a chelating agent may form coordination bonds with more than one metal ion, and a variety of binding modes are possible.

The term "coordination" refers to an interaction in which a multi-electron pair donor binds to a central (metal) ion in a coordinative manner, i.e., shares two or more unshared electron pairs with a central (metal) ion. Chelating agents are preferably selected based on their ability to coordinate the desired central (metal) ion, which in one embodiment is a radionuclide as described herein.

In one embodiment, the chelating group of the radionuclide is selected from bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5- [[4-[5-aminopentyl-(hydroxy)amino]-4-oxobutanoyl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4, 7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid )phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7, 10-tetraazacyclodecane-4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-( (bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1, 4,7-Triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneaminetetraacetic acid) (TMT), 1,4,7-triazacyclononane -1,4,7-tris[methylene(2-carboxyethyl)phosphinic acid](TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid and triethylenetetraaminehexaacetic acid (TTHA) and N ^1- (5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide; preferably 1,4,7,10-tetraazacyclododecane-N,N′,N″,N″′-tetraacetic acid, 1,4,7-triazacyclononanetriacetic acid (NOTA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide.

The choice of radionuclide may depend on the chemical structure and chelating capacity of the chelating groups D and D' and the intended application (eg, diagnostics versus therapy). In one embodiment, the radionuclide is selected from any one of the radioactive cations or anions of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At and Er; preferably, the radionuclide ^is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu.

In a specific embodiment, the chelating group of the present invention is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and the radionuclide is ⁶⁸ Ga. In a specific embodiment, the chelating group of the present invention is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and the radionuclide is ⁶⁴ Cu. In a specific embodiment, the chelating group of the present invention is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and the radionuclide is ¹⁷⁷ Lu.

In some embodiments, Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)-, or -NH-(PEG) _i -(CO)-, wherein the (PEG) _i comprises 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and optionally, a C 1-10 alkylene is attached to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. In some embodiments, i 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, Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and optionally a C _1-10 alkylene group is connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit; preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; more preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-, -NH-PEG ₃ -C ₂ H ₄ -(CO)- or -NH-PEG ₄ -C ₃ H ₆ -(CO)-; further preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. In some embodiments, Ld is -NH-(PEG) _i -C _{1- 10} alkylene-(CO)-, wherein i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. In some embodiments, Ld is -NH-PEG ₄ -(CO)-.

In some embodiments, _L1 and L1 _' are each independently selected from any one of a chemical bond, a _C1-10 alkylene group, -NH-, and -(CO)-, or any combination thereof; preferably, _L1 is selected from -( _CH2 ) _4- NH- or -CO-NH- _{C2H4 -} NH-, and L1 _' is selected from a chemical bond, -( _CH2 ) _{4- NH-} , or -CO-NH- _C2H4 -NH-. In some embodiments, _L1 and L1 _' are the same.

In some embodiments, _L2 and L2 _' are each independently selected from any one of a chemical bond, -(CO)-, _C1-10 alkylene, and -NH-, or any combination thereof; preferably, _L2 is selected from -(CO)- or -( _CH2 ) ₄ -NH-, and L2 _' is selected from a chemical bond, -(CO)-, or -( _CH2 ) ₄ -NH-. In some embodiments, _L2 and L2 _' are the same.

In some embodiments, m is 0. In some embodiments, n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3. In some embodiments, z is an integer selected from 1-10, preferably, z is 1, 2, 3 or 4; more preferably, z is 1.

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -(CH ₂ ) ₄ -NH-, L ₂ is -(CO)-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 1, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ and L _1' are -(CH ₂ ) ₄ -NH-, L ₂ and L _2' are -(CO)-, D and D' are 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

In a specific embodiment, m is 0, n is 3, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-, L ₁ is -CO-NH-C ₂ H ₄ -NH-, L ₂ is -(CH ₂ ) ₄ -NH-, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid, and Q is In a specific embodiment, the compound of formula (II') has the following structure:

Pharmaceutical composition

Another object of the present invention is to provide a pharmaceutical composition comprising a preventively or therapeutically effective amount of the nuclide conjugate of the present invention, and optionally at least one pharmaceutically acceptable carrier.

The pharmaceutical composition of the present invention can be administered in any manner as long as it achieves the effect of preventing, alleviating, preventing or treating the symptoms of humans or animals. For example, various suitable dosage forms can be prepared according to the route of administration, particularly injections such as lyophilized powder injections, injections or sterile injection powders.

The term "pharmaceutically acceptable" means that it does not produce undue toxicity, irritation or allergic reaction when in contact with patient tissues within the scope of normal medical judgment, has a reasonable ratio of advantages to disadvantages, and is effective for the intended use.

The term "pharmaceutically acceptable carrier" refers to any carrier material that is pharmaceutically acceptable and does not interfere with the biological activity and performance of the nuclide conjugates of the present invention. Examples of aqueous carriers include, but are not limited to, buffered saline. Pharmaceutically acceptable carriers also include substances that allow the composition to approach physiological conditions, such as pH adjusters and buffers, toxicity modifiers, sodium acetate, sodium chloride, potassium chloride, calcium chloride, sodium lactate, and the like.

In one embodiment, the pharmaceutical composition of the invention has a nuclide/antibody ratio (DAR) of an integer or non-integer between 0 and 20, such as about 0 to about 10, about 0 to about 8, about 0 to about 6, about 0 to about 4, about 0 to about 3, about 0 to about 2, or about 0 to about 1. In a particular embodiment, the antibody-drug conjugate of the invention has a DAR of about 0.70, about 0.72, about 0.73, or about 0.83.

Treatment methods and uses

The radionuclide-conjugated pharmaceuticals of the present invention can be used for medical treatment and/or diagnosis of related diseases. Related diseases susceptible to treatment with the radionuclide conjugates of the present invention include tumors characterized by specific tumor-associated antigens or cell surface receptors. These tumor cells can be recognized by the targeting moiety of the radionuclide conjugates of the present invention and can be killed by the radionuclide in the radionuclide conjugates.

Therefore, in another aspect, the present invention also provides use of the radionuclide conjugate of the present invention or the pharmaceutical composition of the present invention in the preparation of therapeutic nuclear medicines and/or diagnostic nuclear medicines for diagnosing or treating related diseases.

In another aspect, the present invention provides the radionuclide conjugate of the present invention or the pharmaceutical composition of the present invention for use in diagnosing or treating related diseases.

In a further aspect, the present invention provides a method for diagnosing, delaying or treating a disease, comprising administering to a subject in need thereof an effective amount of the radionuclide conjugate of the present invention or the pharmaceutical composition of the present invention.

In one embodiment, the disease is an autoimmune disease or a tumor. In some embodiments, the related diseases described herein include malignant lymphoma, testicular seminoma, Wilms' tumor, neuroblastoma, medulloblastoma, Ewing sarcoma, small cell lung cancer, head and neck squamous cell carcinoma, esophageal squamous cell carcinoma, lung squamous cell carcinoma, breast cancer, cervical cancer, skin cancer, gastrointestinal adenocarcinoma, pancreatic cancer, prostate cancer, fibrosarcoma, liposarcoma, and rhabdomyosarcoma.

The dosage of the antibody-drug conjugate administered to a subject can be adjusted to a considerable extent. The dosage can vary depending on the specific route of administration and the needs of the subject and can be subject to the judgment of a healthcare professional.

Dosage and kit

The conjugates, radionuclide conjugates and pharmaceutical compositions according to the present invention will be administered alone or in combination with additional therapeutic agents in an effective amount by any common and acceptable means known in the art. The effective amount may vary depending on the severity of the disease, the age and relative health of the subject, the potency of the compound used, and other factors known to those skilled in the art.

As a general example, a daily dosage of about 0.001 to about 100 mg/kg body weight can be used, or more particularly about 0.03 to 2.5 mg/kg body weight. In larger mammals, such as humans, the daily dosage can be in the range of about 0.5 mg to about 2000 mg.

As another example, about 5.6 GBq (150 mCi) to about 9.3 GBq (250 mCi) can be used every six weeks, or in particular, about 7.4 GBq (200 mCi) can be used every six weeks. Wherein, Becquerel (Bq) is the international unit of radioactivity, which represents the radioactivity intensity of one nucleus decaying per second. Curie (Ci) is the original unit of radioactivity, 1 Curie (Ci) = 3.7×10 ¹⁰ Becquerel (Bq). The conjugates, radionuclide conjugates and pharmaceutical compositions of the present invention are generally administered in the form of pharmaceutical compositions comprising a pharmaceutically active ingredient and various other pharmaceutically acceptable components, for example, see Remington's Pharmaceutical Science (15th ed., Mack Publishing Company, Easton, Pa., 1980). The preferred or desired form depends on the intended mode of administration and therapeutic application. Depending on the desired formulation, the composition may also include a pharmaceutically acceptable non-toxic carrier or diluent, which is defined as a carrier commonly used to formulate a pharmaceutical composition for administration to animals or humans. The choice of diluent does not affect the biological activity of the combination. Examples of diluents include, but are not limited to, distilled water, physiological phosphate-buffered saline, Ringer's solution, dextrose solution, and Hank's solution. In addition, the pharmaceutical composition or formulation may also include other carriers, adjuvants, or non-toxic, non-therapeutic, non-immunogenic stabilizers.

The conjugates, radionuclide conjugates and pharmaceutical compositions of the present invention can be administered in the form of pharmaceutical compositions by any conventional route; for example, enterally, such as orally, for example in the form of tablets or capsules; parenterally, for example in the form of injectable solutions or suspensions; or topically, for example, ophthalmically or nasally, for example in the form of emulsions, gels, ointments, creams or suppositories.

In one embodiment, the pharmaceutical composition is a solution of the active ingredient, including a suspension or dispersion, such as an isotonic aqueous solution. For a lyophilized composition comprising only the active ingredient or comprising the active ingredient and a carrier (such as mannitol), a dispersion or suspension can be prepared before use.

The limiting examples of carriers include fillers, such as sugars, such as lactose, sucrose, mannitol or sorbitol, cellulose preparations and/or calcium phosphates, such as tricalcium phosphate or calcium hydrogen phosphate, and binders, such as starches, such as corn, wheat, rice or potato starch, methylcellulose, hydroxypropyl methylcellulose, sodium carboxymethylcellulose and/or polyvinyl pyrrolidone, and/or if necessary, disintegrants, such as the above-mentioned starches, carboxymethyl starch, cross-linked polyvinyl pyrrolidones, alginic acid or its salts, such as sodium alginate. Other carriers include, but are not limited to, rheology modifiers and lubricants, such as silicic acid, talc, stearic acid or its salts, such as magnesium or calcium stearate, and/or polyethylene glycol or its derivatives.

The present invention also provides a pharmaceutical combination, such as a kit, comprising a) a first agent, which is a radionuclide conjugate according to the present invention or a pharmaceutically acceptable salt thereof, and b) instructions for administration.

Beneficial effects

The present invention provides a novel radionuclide conjugate that can achieve one-step, site-specific coupling of an albumin-binding unit and a chelating group to an engineered targeting moiety (such as Fab, scFv, nanobody, and sdAb) via ligase-catalyzed site-specific coupling to produce the corresponding conjugate. The conjugate of the present invention has a uniform and stable structure, retaining the antigen-binding ability of the original targeting moiety and exhibiting excellent in vitro stability. Furthermore, the conjugation process is simple and easily scalable.

Compared to existing technologies, the radionuclide conjugates of the present invention possess an appropriate blood circulation half-life, exhibit higher tumor accumulation, and have a longer tumor retention time, demonstrating enhanced anti-tumor activity. Furthermore, the radionuclide conjugates of the present invention have a stable structure, a low off-target rate, and significantly reduced toxic side effects. In particular, only a moderate amount of radionuclide is required to achieve the desired therapeutic effect, resulting in a lower total absorbed radiation dose for the patient. Furthermore, manufacturing costs are reduced while also alleviating environmental burdens.

Example

The solution of the present invention is further described in detail below with reference to specific embodiments.

It should be noted that the following examples are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the present invention. For those skilled in the art, other variations or modifications may be made based on the description of the present invention. It is not necessary and is not possible to exhaustively enumerate all embodiments herein, and the obvious variations or modifications derived therefrom are still within the scope of protection of the present invention. Unless otherwise indicated, the instruments, equipment, and reagents used herein are all commercially available.

Example 1: Synthesis of compound LP0

1.1 Synthesis of intermediate compound LP0a

Step 1: Swelling and condensation of the resin

Weigh 2-CTC-Resin (CAS No. 42074-68-0, 1.9 g, 2.0 mmol) into a solid-phase synthesis tube, add dichloromethane (20 mL), stir to mix, and allow to swell for 30 minutes before filtering. Weigh Fmoc-Lys(Dde)-OH (CAS No. 150629-67-7, 3.2 g) into a conical flask, add dichloromethane (20 mL), and shake to dissolve completely. Subsequently, add diisopropylethylamine (0.78 g) to the conical flask and mix thoroughly. Pour the solution from the conical flask into the solid-phase synthesis tube and stir to mix thoroughly. After bubbling nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours, add a methanol/diisopropylethylamine mixture (6 mL, v/v = 5:1) to the system and cap it for 30 minutes. Subsequently, the reaction system was filtered and washed once with dichloromethane (20 mL) and three times with N,N'-dimethylformamide, each time using 20 mL.

Step 2: Deprotection and condensation

Add the Fmoc protection removal reagent solution (N, N'-dimethylformamide/piperidine = 4:1, containing 1% 1-hydroxybenzotriazole (HOBt, 20 mL) to the solid phase synthesis tube in the previous step and stir to react for 10 minutes, and the reaction system is completely filtered. Then add the same Fmoc protection reagent solution (20 mL) and stir to react for 10 minutes, and the reaction system is completely filtered. Subsequently, the resin is washed four times with N, N'-dimethylformamide, each time using 20 mL. The resin is detected with ninhydrin and appears dark blue.

Weigh Fmoc-PEG ₄ -CH ₂ CH ₂ COOH (CAS No. 557756-85-1, 2.9 g) and Oxyma (CAS No. 57361-81-6, 0.8 g) into a conical flask. Add N,N'-dimethylformamide (20 mL) and shake to dissolve completely. Add N,N'-diisopropylcarbodiimide (DIC, 0.75 g) to the conical flask, mix thoroughly, and activate at 0-10°C for 3-5 minutes. Then, add the solution from the conical flask to the solid-phase synthesis tube described above and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Detect the resin using ninhydrin until it is essentially colorless. Drain the solvent from the reaction system and wash with N,N'-dimethylformamide three times, using 20 mL each wash.

Step 3: Deprotection and condensation

Add the Fmoc protection removal reagent solution (N, N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt (20 mL) to the solid phase synthesis tube in the previous step, stir and react for 10 minutes, and filter the reaction system completely. Add the same Fmoc protection reagent solution (20 mL) and stir and react for 10 minutes, and filter the reaction system completely. Subsequently, wash the resin four times with N, N'-dimethylformamide, using 20 mL each time. The resin is detected with ninhydrin, and it appears dark blue.

Weigh Boc-Gly-Gly-Gly-OH (CAS No. 28320-73-2, 1.7 g) and Oxyma (CAS No. 57361-81-6, 0.8 g) into an Erlenmeyer flask. Add N,N'-dimethylformamide (20 mL) and shake to dissolve completely. Add DIC (0.75 g) to the Erlenmeyer flask, mix thoroughly, and activate at 0-10°C for 3-5 minutes. Then, add the solution from the Erlenmeyer flask to the solid-phase synthesis tube described above and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Check the resin with ninhydrin until it is essentially colorless. Drain the solvent from the reaction system and wash twice with 20 mL of N,N'-dimethylformamide and three times with 20 mL of dichloromethane. Drain the solvent from the reaction system and air-dry the resin until it becomes a quicksand.

Step 4: Cleavage and purification

To a round-bottom flask, add dichloromethane (28 mL) and hexafluoroisopropanol (12 mL), mix thoroughly, and add the resin obtained in the previous step to the solution. Stir and react for approximately 2 hours. The reaction system is filtered, and the resin is washed with a small amount of dichloromethane. The resulting filtrate is concentrated under reduced pressure and purified using reverse-phase high-performance liquid chromatography (RP-HPLC). The resulting product is lyophilized to obtain pure LP0a (1.4 g) in an 85% yield. LC-MS analysis reveals [M+H] ⁺ = 829.44.

1.2 Synthesis of intermediate compound LP0b

(E)-4-amino-6-(((4'-amino-3,3'-dimethyl-[1,1'-biphenyl]-4-yl)diazenyl)-5-hydroxynaphthalene-1,3-disulfonic acid (EB-NH ₂ , 0.3 g, 1.0 eq.) and LP0a (1.37 g, 3.0 eq.) were weighed into a round-bottom flask, and N,N'-dimethylformamide (12 mL) was added and stirred to dissolve completely. Subsequently, 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU, 0.84 g, 4.0 eq.) and diisopropylethylamine (548 μL, 6.0 eq.) were added to the system. The reaction system was stirred at room temperature overnight, and the EB-NH 2 reaction was monitored by high performance liquid chromatography (HPLC). ₂ until the reaction is substantially complete. The product was purified by reverse-phase high performance liquid chromatography and lyophilized to obtain pure LP0b (0.36 g) in a 49% yield. LC-MS analysis showed [M+H] ⁺ = 1352.55.

1.3 Synthesis of intermediate compound LP0c

Step 1: Deprotection

Compound LP0b (0.36 g) was weighed into a round-bottom flask, purified water (8 mL) was added, and the mixture was stirred thoroughly. Hydrazine hydrate (0.4 mL) was then added, and the reaction system was stirred at room temperature for 1 hour. The reaction was monitored by HPLC until nearly complete. The product was purified by reverse-phase HPLC and lyophilized to obtain pure LP0b-1 (0.15 g) in a 47% yield. LC-MS analysis revealed [M+H] ⁺ = 1189.6.

Step 2: Condensation

Compound LP0b-1 (0.15 g, 1.0 eq.) and tri-tert-butyl 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA-(COO ^t Bu) ₃ , 80 mg, 1.1 eq.) were weighed into a round-bottom flask. N,N'-dimethylformamide (6 mL) was added and stirred until completely dissolved. HATU (72 mg, 1.5 eq.) and diisopropylethylamine (63 μL, 3.0 eq.) were then added. The reaction was stirred at room temperature overnight and monitored by HPLC until nearly complete. The product was purified by reverse-phase HPLC and lyophilized to obtain pure LP0c (0.125 g) in a 60% yield. LC-MS analysis revealed [1/2 M+H] ⁺ = 872.89.

1.4 Synthesis of compound LP0

Compound LP0c (0.12 g) was weighed into a round-bottom flask and a mixture of purified water and trifluoroacetic acid (2 mL, v/v = 5:95) was added and stirred. The mixture was allowed to react at room temperature for 2 hours and monitored by HPLC until nearly complete. The product was purified by reverse-phase HPLC and lyophilized to obtain pure LP0 (74 mg) in a 73% yield. LC-MS analysis revealed [M+H] ⁺ = 1476.4.

Example 2: Synthesis of compound LP1

Step 1: Swelling and condensation of the resin

Weigh 2-CTC-Resin (CAS No. 42074-68-0, 1.9 g, 2.0 mmol) into a solid-phase synthesis tube, add dichloromethane (20 mL), stir to mix, and allow to swell for 30 minutes before filtering. Weigh Fmoc-Lys(Dde)-OH (CAS No. 150629-67-7, 3.2 g) into a conical flask, add dichloromethane (20 mL), and shake to dissolve completely. Subsequently, add diisopropylethylamine (0.78 g) to the conical flask and mix thoroughly. Pour the solution from the conical flask into the solid-phase synthesis tube and stir to mix thoroughly. After bubbling nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours, add a methanol/diisopropylethylamine mixture (6 mL, v/v = 5:1) to the system and cap it for 30 minutes. Subsequently, the reaction system was filtered and washed once with dichloromethane (20 mL) and three times with N,N'-dimethylformamide, each time using 20 mL.

Step 2: Deprotection and condensation

Add the Fmoc protection removal reagent solution (N, N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt (20 mL) to the solid phase synthesis tube in the previous step, stir and react for 10 minutes, and filter the reaction system completely. Add the same Fmoc protection reagent solution (20 mL) and stir and react for 10 minutes, and filter the reaction system completely. Subsequently, wash the resin four times with N, N'-dimethylformamide, using 20 mL each time. The resin is detected with ninhydrin, and it appears dark blue.

Weigh p-toluenebutyric acid (1.07 g) and Oxyma (0.8 g) into a conical flask, add N,N’-dimethylformamide (20 mL), and shake to dissolve completely. Then add DIC (0.75 g) to the conical flask, mix well, and place at 0-10°C for activation for 3-5 minutes. Subsequently, add the solution in the conical flask to the above-mentioned solid phase synthesis tube and stir to mix. Then, bubble nitrogen from the bottom of the solid phase synthesis tube to react for about 2 hours, and use ninhydrin to detect the resin until it is basically colorless. Drain the solvent in the reaction system and wash three times with N,N’-dimethylformamide, using 20 mL each time.

Step 3: Deprotection and condensation

Add Dde protection reagent solution (N,N'-dimethylformamide/hydrazine hydrate = 95:5, 20 mL) to the solid-phase synthesis tube in the previous step, stir and react for 10 minutes, and filter the reaction system completely. Add the same Dde protection reagent solution (20 mL) and stir and react for 10 minutes, and filter the reaction system completely. Subsequently, wash the resin four times with N,N'-dimethylformamide, using 20 mL each time. Use ninhydrin to detect the resin, and it will appear dark blue.

Weigh Fmoc-PEG ₄ -CH ₂ CH ₂ COOH (2.9 g) and Oxyma (0.8 g) into a conical flask, add N,N'-dimethylformamide (20 mL), and shake to dissolve completely. Add DIC (0.75 g) to the conical flask, mix thoroughly, and activate at 0-10°C for 3-5 minutes. Then, add the solution in the conical flask to the solid-phase synthesis tube described above and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Check the resin with ninhydrin until it is essentially colorless. Drain the solvent from the reaction system and wash three times with 20 mL of N,N'-dimethylformamide each time.

Step 4: Deprotection and condensation

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 20 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. The reaction system was then completely filtered. The same Fmoc deprotection reagent solution (20 mL) was added and stirred for 10 minutes. The reaction system was then completely filtered. Subsequently, the resin was washed four times with N,N'-dimethylformamide, using 20 mL each time. The resin was detected with ninhydrin, which indicated a dark blue color.

Weigh Boc-Gly-Gly-Gly-OH (1.7 g) and Oxyma (0.8 g) into a conical flask, add N,N’-dimethylformamide (20 mL), and shake to dissolve completely. Add DIC (0.75 g) to the conical flask, mix thoroughly, and activate at 0-10°C for 3-5 minutes. Subsequently, add the solution in the conical flask to the solid-phase synthesis tube described above and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Check the resin with ninhydrin until it is essentially colorless. Drain the solvent from the reaction system and wash twice with N,N’-dimethylformamide, using 20 mL each time, and then wash three times with dichloromethane, using 20 mL each time. Drain the solvent from the reaction system and air-dry the resin until it becomes a quicksand.

Step 5: Cleavage and purification

To a round-bottom flask, add dichloromethane (28 mL) and hexafluoroisopropanol (12 mL), mix thoroughly, and add the resin obtained in the previous step to the solution. Stir and react for approximately 2 hours. The reaction system is filtered, and the resin is washed with a small amount of dichloromethane. The resulting filtrate is concentrated under reduced pressure and purified by reverse-phase high-performance liquid chromatography. The resulting product is lyophilized to obtain pure LP1a (1.3 g) in a yield of 79%. LC-MS analysis shows [M+H] ⁺ = 825.37.

2.2 Synthesis of intermediate compound LP1b

LP1a (0.78 g, 1.0 eq.) and Fmoc-ethylenediamine hydrochloride (0.3 g, 1.0 eq.) were weighed into a round-bottom flask. N,N'-dimethylformamide (10 mL) was added and stirred until completely dissolved. Diisopropylethylamine (620 μL, 4.0 eq.) was then added. HATU (0.54 g, 1.5 eq.) was then added, and the reaction system was stirred at room temperature for approximately 2 hours. The reaction was monitored for near completion by HPLC. The product was purified by reverse-phase HPLC and lyophilized to obtain pure LP1b (0.94 g) in a 92% yield. LC-MS analysis revealed [M+H] ⁺ = 1089.53.

2.3 Synthesis of intermediate compound LP1c

Compound LP1b (0.5 g, 1.0 eq.) was weighed into a round-bottom flask, and N,N'-dimethylformamide (5 mL) was added and stirred until completely dissolved. Subsequently, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 35 μL, 0.5 eq.) was added to the mixture, and the mixture was stirred at room temperature for 1.5 hours. The reaction was monitored by HPLC until nearly complete. DOTA-(COO ^t Bu) ₃ (0.26 g, 1.0 eq.) and HATU (0.26 g, 1.5 eq.) were then added and stirred to dissolve. Diisopropylethylamine (305 μL, 4.0 eq.) was then added, and the reaction was stirred at room temperature overnight. The reaction was monitored by HPLC until nearly complete. The product was purified by reverse-phase HPLC and lyophilized to yield pure LP1c (0.33 g) in a 51% yield. The result of LC-MS detection was [M+H] ⁺ =1421.77.

2.4 Synthesis of compound LP1

Compound LP1c (0.23 g) was weighed into a round-bottom flask and a mixture of purified water and trifluoroacetic acid (2.5 mL, v/v = 5:95) was added and stirred. The reaction was allowed to react at room temperature for 3 hours and monitored by HPLC until nearly complete. The product was purified by reverse-phase HPLC and lyophilized to obtain pure LP1 (115 mg) in a 62% yield. LC-MS analysis revealed [M+H] ⁺ = 1153.6.

Example 3: Synthesis of Compound LP2

Referring to the synthesis method of compound LP1 in Example 2, compound LP2 was prepared by using 4-(4-iodophenyl)butyric acid instead of p-tolylbutyric acid to obtain pure compound LP2 (150 mg). The LC-MS detection result was [M+H] ⁺ =1265.44.

Example 4: Synthesis of Compound LP3 (Control)

Referring to the synthesis method of compound LP1 in Example 2, compound LP3 was prepared by using acetic acid instead of p-toluenebutyric acid, and finally pure compound LP3 (140 mg) was obtained. The LC-MS detection result was [M+H] ⁺ =1035.51.

Example 5: Synthesis of Compound LP4

(1) Resin swelling and coupling with ethylenediamine:

Weigh 450 mg of 2-CTC-Resin into a solid-phase synthesis tube, add dichloromethane (6 mL), stir to mix, and allow to swell for 30 minutes before draining the solvent. Measure 107 μL of ethylenediamine into an EP tube, add dichloromethane (6 mL), and shake to dissolve completely. Then, add diisopropylethylamine (600 μL) to a conical flask and mix thoroughly. Add the above solution to the solid-phase synthesis tube and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Then, add a methanol/diisopropylethylamine mixture (3 mL, v/v = 5:1) to the system and cap it for 30 minutes. Then, filter and wash once with dichloromethane (10 mL) and three times with 10 mL of N,N'-dimethylformamide.

(2) Coupling of Fmoc-Lys(Dde)-OH:

Weigh Fmoc-Lys(Dde)-OH (920 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(3) Deprotection and coupling of Fmoc-PEG ₄ -OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-PEG ₄ -OH (585 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(4) Deprotection and coupling with Fmoc-Gly-Gly-OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-Gly-Gly-OH (567 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(5) Deprotection and condensation of Boc-Gly-OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Boc-Gly-OH (280 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube, add DMF (12 mL), and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(6) Deprotection and coupling of ibuprofen

Add the DDE protecting agent solution (N,N'-dimethylformamide/hydrazine hydrate = 95:5, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Then, filter thoroughly, add the same DDE protecting agent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Then, wash four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh ibuprofen (330 mg) and Oxyma (432 mg) into a PE tube, add N,N'-dimethylformamide (6 mL), and mix thoroughly to dissolve. Finally, add DIC (300 μL), shake thoroughly, and add the solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which is essentially colorless. Drain the solvent and wash twice with N,N'-dimethylformamide (10 mL each) and three times with dichloromethane (10 mL each). Drain the solvent and air-dry the resin until it becomes a quicksand.

(7) Cutting

Add dichloromethane (7 mL) and hexafluoroisopropanol (3 mL) to a round-bottom flask and mix thoroughly. Add the resin obtained in the previous step to the solution and stir for approximately 2 hours. Filter and wash the resin with a small amount of dichloromethane. Concentrate the filtrate under reduced pressure to obtain the crude peptide as an oil, which is then weighed.

(8) Coupling of DOTA

Weigh DOTA (916 mg) and HOBt (212 mg) into a PE tube, add N,N'-dimethylformamide (1 mL), and mix thoroughly to dissolve. Add the above solution to a 50 mL round-bottom flask containing the crude peptide, add dichloromethane (5 mL), and shake evenly. Slowly add DIC (300 μL) dropwise. Stir the reaction overnight, then dry the solution on a rotary evaporator to obtain the pure product.

(9) Deprotection and purification

Prepare 10 mL of conventional cutting solution: phenol (500 mg), tips (1 mL), purified water (0.5 mL), and dilute to 10 mL with TFA. Pour the above deprotection solution into the pure product obtained in (8) and stir to react for 2 hours. Add ice ether (20 mL) and fully precipitate. Then centrifuge at 3500 rpm for 3 minutes; after centrifugation, discard the supernatant and centrifuge three times. Dry at room temperature. The obtained pure product was separated by semi-preparative liquid chromatography and lyophilized to obtain compound LP4 (20 mg, purity 99.74%) with a total yield of 11%. The LC-MS test result was [M+H] ⁺ = 1182.4, which was consistent with the theory.

Example 6: Synthesis of Compound LP5

Compound LP5 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. The LC-MS result showed [M+H] ⁺ =1277.35, which was consistent with the theoretical value.

Example 7: Synthesis of Compound LP6

Compound LP6 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [M+H] ⁺ = 1120.25, consistent with theoretical results.

Example 8: Synthesis of Compound LP7

Compound LP7 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [1/2M+H] ⁺ = 630.6, consistent with theoretical results.

Example 9: Synthesis of Compound LP8

Compound LP8 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [M+H] ⁺ = 1279.85, consistent with theoretical results.

Example 10: Synthesis of Compound LP9

Compound LP9 was synthesized according to the above-described route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [M+H] ⁺ = 1131.45, consistent with theoretical results.

Example 11: Synthesis of Compound LP10

Compound LP10 was synthesized according to the above-described route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [1/2M+H] ⁺ = 676.70, consistent with theoretical results.

Example 12: Synthesis of Compound LP11

(1) Resin swelling and coupling with ethylenediamine:

Weigh 450 mg of 2-CTC-Resin into a solid-phase synthesis tube, add dichloromethane (6 mL), stir to mix, and allow to swell for 30 minutes before draining the solvent. Measure 107 μL of ethylenediamine into an EP tube, add dichloromethane (6 mL), and shake to dissolve completely. Then, add diisopropylethylamine (600 μL) to a conical flask and mix thoroughly. Add the above solution to the solid-phase synthesis tube and stir to mix thoroughly. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Then, add a methanol/diisopropylethylamine mixture (3 mL, v/v = 5:1) to the system and cap it for 30 minutes. Then, filter and wash once with dichloromethane (10 mL) and three times with 10 mL of N,N'-dimethylformamide.

(2) Coupling of Fmoc-Lys(Dde)-OH:

Weigh Fmoc-Lys(Dde)-OH (920 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(3) Deprotection and coupling of Fmoc-PEG ₄ -OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-PEG ₄ -OH (585 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(4) Deprotection and coupling with Fmoc-Lys(Dde)-OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-Lys(Dde)-OH (920 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(5) Deprotection and coupling of Fmoc-PEG ₄ -OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-PEG ₄ -OH (585 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(6) Deprotection and coupling with Fmoc-Gly-Gly-OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes, then filter completely. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes, then filter completely. Subsequently, wash the mixture four times with 20 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Fmoc-Gly-Gly-OH (567 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube. Add DMF (12 mL) and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(7) Deprotection and condensation of Boc-Gly-OH

Add the Fmoc deprotection reagent solution (N,N'-dimethylformamide/piperidine = 4:1, containing 1% HOBt, 10 mL) to the previous solid-phase synthesis tube and stir for 10 minutes. Filter thoroughly. Add the same Fmoc deprotection reagent solution (10 mL) and stir for 10 minutes. Filter thoroughly. Subsequently, wash the mixture four times with 10 mL of N,N'-dimethylformamide. Detect the resin with ninhydrin, which should yield a dark blue color.

Weigh Boc-Gly-OH (280 mg), HATU (576 mg), and HOAT (208 mg) into a PE tube, add DMF (12 mL), and mix thoroughly to dissolve. Finally, add diisopropylethylamine (600 μL) and shake thoroughly. Add the resulting solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube for approximately 2 hours. Ninhydrin is used to detect the resin, which remains essentially colorless. Drain the solvent and wash the mixture three times with 10 mL of N,N'-dimethylformamide.

(8) Deprotection and coupling with p-iodophenylbutyric acid

Add Dde protection reagent solution (N,N'-dimethylformamide/hydrazine hydrate = 95:5, 10 mL) to the solid phase synthesis tube in the previous step and stir for 10 minutes. Then, filter completely with suction, add the same Dde protection reagent solution (10 mL) and stir for 10 minutes, and filter completely with suction. Subsequently, wash with N,N'-dimethylformamide four times, 10 mL each time. Use ninhydrin to detect the resin, and it will turn dark blue.

Weigh p-iodophenylbutyric acid (696 mg) and Oxyma (864 mg) into a PE tube, add N,N'-dimethylformamide (10 mL), and mix thoroughly to dissolve. Finally, add DIC (600 μL), shake thoroughly, and add the solution to a synthesis tube. Then, bubble nitrogen through the bottom of the solid-phase synthesis tube to react for approximately 2 hours. Ninhydrin is used to detect the resin, which is essentially colorless. Drain the solvent and wash twice with N,N'-dimethylformamide (10 mL each) and three times with dichloromethane (10 mL each). Drain the solvent and air-dry the resin until it becomes a quicksand.

(9) Cutting

Add dichloromethane (7 mL) and hexafluoroisopropanol (3 mL) to a round-bottom flask and mix thoroughly. Add the resin obtained in the previous step to the solution and stir for approximately 2 hours. Filter and wash the resin with a small amount of dichloromethane. Concentrate the filtrate under reduced pressure to obtain the crude peptide as an oil, which is then weighed.

(10) Coupling of DOTA

Weigh DOTA (916 mg) and HOBt (212 mg) into a PE tube, add N,N'-dimethylformamide (1 mL), and mix thoroughly to dissolve. Add the above solution to a 50 mL round-bottom flask containing the crude peptide, add dichloromethane (5 mL), and shake evenly. Slowly add DIC (300 μL) dropwise. Stir the reaction overnight, then dry the solution on a rotary evaporator to obtain the pure product.

(11) Deprotection and purification

Prepare 10 mL of conventional cutting solution: phenol (500 mg), tips (1 mL), purified water (0.5 mL), and dilute to 10 mL with TFA. Pour the above deprotection solution into the pure product obtained in (8) and stir to react for 2 hours. Add ice ether (20 mL) and fully precipitate. Then centrifuge at 3500 rpm for 3 minutes; after centrifugation, discard the supernatant and centrifuge three times. Dry at room temperature. The obtained pure product was separated by semi-preparative liquid chromatography and lyophilized to obtain LP11 (20 mg, purity 96.46%). The LC-MS test result was [1/2M+H] ⁺ = 957.25, which was consistent with the theory.

Example 13: Synthesis of Compound LP12

Referring to the synthesis method of compound LP4 in Example 5, compound LP12 was synthesized according to the above route. LC-MS analysis was consistent with the theoretical results.

Example 14: Synthesis of Compound LP13

Compound LP13 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [1/2M+H] ⁺ = 816.70, consistent with theoretical results.

Example 15: Synthesis of Compound LP14

Compound LP14 was synthesized according to the above route, referring to the synthesis method of compound LP4 in Example 5. LC-MS analysis showed [1/2M+H] ⁺ = 665.50, consistent with theoretical results.

Example 16: Synthesis of Compound H0274

A positive control targeted radionuclide conjugate precursor, H0274, was synthesized using the method described in Mol. Pharmaceutics 2018, 15, 934-946. LC-MS analysis revealed [M+H] ⁺ = 1330.95, consistent with theoretical results.

Example 17: Preparation of a monoclonal single-domain antibody specifically targeting human prostate-specific membrane antigen (PSMA)

17.1 Vector Construction and Expression

A monoclonal single-domain antibody with high affinity and specificity targeting human PSMA was selected, and its sequence is shown in the table below.

Note: Antibodies Ab60 and Ab61 are unmodified VHH; antibody Ab62 is a modified VHH: its C-terminus is sequentially connected with a linker sequence (GA), a sortase enzyme donor substrate recognition sequence (LPETGG, SEQ ID NO: 18) and a purification sequence (HHHHHH, SEQ ID NO: 20); Ab62 antibody removes the sequence GGHHHHHH (SEQ ID NO: 19) under the action of sortase enzyme and connects it to the glycine in formula (I); antibody Ab63 is a modified VHH: its C-terminus is sequentially connected with a linker sequence (GGGGSGGGGS, SEQ ID NO: 15) and a sortase enzyme donor substrate recognition sequence (LPETGG, SEQ ID NO: 18); Ab63 antibody removes the sequence GG under the action of sortase enzyme and connects it to the glycine in formula (I).

To generate an expression vector encoding an anti-human PSMA single-domain antibody, the nucleic acid sequence for the single-domain antibody was cloned into the pCDNA 3.4 vector. This was then transformed into competent E. coli cells via ligation, and single clones were isolated and sequenced. Positive clones were cultured and amplified, and plasmids were extracted to obtain a eukaryotic expression plasmid for the antibody. This plasmid was then transformed into suspension-adapted Chinese hamster ovary (CHO) cells by electroporation. Following electroporation, cells were evenly distributed into shake flasks containing 100 ml of culture medium and incubated statically for 40 minutes. Following incubation, the shake flasks were incubated at 37°C, 120 rpm, and 8% _CO₂ for antibody harvest.

17.2 Antibody Purification

The antibody was purified by Ni affinity chromatography. First, 20 ml 1x PBS was used at a flow rate of 1 ml/min to equilibrate the column. After loading, the column was washed with 20 ml 1x PBS, 5 mM imidazole (pH 8.0) at a flow rate of 1 ml/min. The sample was then eluted with 150 mM imidazole (pH 8.0) at 1 ml/min and collected in separate tubes. The absorbance at 280 nm was read using a NanoDrop instrument. The high-concentration protein was transferred to a dialysis bag and placed in a beaker of 50 mM Tris + 150 mM NaCl, pH 8.0 for dialysis.

Example 18: Preparation of Conjugate Ab62-LP1

18.1 Experimental Principles

Immobilized Sortase specifically recognizes and cleaves the enzyme recognition site (e.g., LPETGG) on engineered small antibody fragments (such as Fab, scFv, nanobody, sdAb, and affibody), and site-specifically couples the fragment to a structure (i.e., Formula II) to which a radionuclide chelating group is attached, thereby forming a corresponding conjugate.

18.2 Preparation of Immobilized Sortase

Halo-Sortase and Chloro resin (see WO2022160156A) are mixed and incubated at room temperature for 10 minutes to 24 hours. The mixture is then eluted with 20mM Tris-HCl, 150mM NaCl, pH 6.0-10.0 buffer. The immobilized Sortase is tested for activity. If qualified, the immobilized ligase (i.e., Sortase enzyme) resin is washed with 20mM Tris-HCl, 150mM NaCl and stored at 4°C until use.

18.3 Coupling and Purification

The single-domain antibody Ab62 is treated by ultrafiltration, dialysis or desalting column method, and its buffer is replaced with a solution of 50mM Tris-HCl, 150mM NaCl, pH=5.0-8.0.

The single-domain antibody Ab62 and the compound LP1 are thoroughly mixed in an appropriate molar ratio (1:1 to 1:100), added to a certain amount of immobilized Sortase enzyme, and a certain amount of buffer solution and _CaCl2 solution are added and mixed evenly. The above system is coupled at 4-40°C for 0.5-20 hours. After the reaction is completed, centrifuge and take the supernatant. Add an appropriate amount of EDTA solution to the supernatant and incubate at room temperature for 0.1-5 hours. Subsequently, it is purified, ultrafiltered or dialyzed to remove unreacted small molecules. The purified conjugate Ab62-LP1 is stored in acetate buffer at an appropriate pH value at 4°C or -80°C until use.

18.4 Detection of the number of chelating groups (DAR value) in the conjugate Ab62-LP1

HIC-HPLC was used to detect the number of structures (DAR value) of chelating groups connected to radionuclides coupled to the single-domain antibody in the conjugate Ab62-LP1. The specific method is as follows:

Chromatographic column: Proteomix HIC Butyl-NP5, 4.6*100mm, 5μm, Non-Porous chromatographic column (Manufacturer: Saifen, PN: 431NP5-4610);

Mobile phase A: 1.5 M ammonium sulfate + 20 mM phosphate buffer, pH 7.0;

Mobile phase B: a mixture of 20 mM phosphate buffer, pH 7.0, and isopropanol in a 7:3 volume ratio.

Flow rate: 0.8 mL/min;

Detection wavelength: 280nm

Elution gradient: 0-8 min, phase B increased from 10% to 100%;

The test results are shown in Figure 1. Based on the peak area, it can be calculated that an average of approximately 0.79 structures of chelating groups connected to radionuclides are coupled to a single domain antibody Ab62, that is, the DAR of the conjugate Ab62-LP1 is 0.79.

18.5 Purity Testing of Conjugate Ab62-LP1

The purity of the conjugate Ab62-LP1 was tested using SEC-HPLC. The specific method is as follows:

Chromatographic column: TSKgel G3000SWXL 7.8mm I.D.*30cm, 5μm chromatographic column (Manufacturer: Tosoh, PN: 0008541);

Mobile phase: a mixture of 2× PBS and acetonitrile, with a volume ratio of 90:10;

Flow rate: 1.0 mL/min;

Detection wavelength: 280nm

The test results are shown in FIG2 . Based on the peak area, it can be calculated that the purity of the conjugate Ab62-LP1 is close to 100%.

Example 19: Preparation of Conjugates Ab62-LP0, Ab62-LP2, Ab62-LP3 and Ab63-LP1

Referring to the preparation method of Example 18, compound LP1 was replaced with compound LP0, compound LP2, and compound LP3 to prepare conjugates Ab62-LP0, Ab62-LP2, and Ab62-LP3, respectively; single-domain antibody Ab62 was replaced with single-domain antibody Ab63 to prepare conjugate Ab63-LP1. The resulting conjugates were further purified and subjected to DAR testing. The results are shown in the following table:

Example 20: Conjugate affinity detection (SPR method)

The affinity of the single-domain antibody Ab62 and its conjugates (Ab62-LP1, Ab62-LP2, and Ab62-LP3) for human PSMA was measured on a Biacore T200 molecular interaction instrument.

First, a 1× HBS-EP solution was prepared as the running buffer for the entire assay system. Human PSMA protein was diluted to 15 μg/mL in 10 mM sodium acetate (pH 4.5) and coupled to channels 2-4 of a Series S CM5 biochip using the amino coupling reagent EDC-NHS at approximately 2500 RU. Subsequently, the protein was quenched in 1 M ethanolamine (pH 8.5). Channel 1 was left untreated as a blank subtraction channel. The single-domain antibodies and conjugates to be tested were diluted twofold in 1× HBS-EP solution, starting at 10 nM and continuing to 0.625 nM. The affinity of these samples to the human PSMA-coupled Series S CM5 biochip was measured sequentially in single-cycle mode, starting from the lowest analyte concentration and increasing in affinity. The analysis temperature was 25°C, the data acquisition frequency was 10 Hz, the flow rate was 30 μL/min, and the association and dissociation times were 120 s and 600 s, respectively. After data acquisition, the sensorgram traces of each sample were blank-subtracted using Biacore T200 Evaluation Software 3.2.1. Kinetic analysis using a 1:1 binding model was performed using the subtracted sensorgram traces to calculate the binding affinity of the single-domain antibody and conjugate to the human PSMA antigen. The results are shown in the following table:

According to the results in the above table, the affinities of conjugates Ab62-LP1, Ab62-LP2 and Ab62-LP3 are not significantly different from those of Ab62, indicating that conjugation of different load-linkers does not affect the affinity of the single-domain antibody.

Example 21: Conjugate affinity detection (FACS method)

Using the PSMA ⁺ PC-3 tumor cell line, conventional FACS methods were used to determine the affinity of conjugates Ab62-LP1, Ab62-LP2, Ab62-LP3, and the single-domain antibody Ab62 for PSMA-positive tumor cells. The results are shown in Figure 3. It can be seen that conjugation of different cargo-linkers does not affect the affinity of the single-domain antibodies for tumor cells.

Example 22: Detection of endocytic activity of conjugates

Using the PSMA ⁺ PC-3 tumor cell line and conventional endocytosis activity assays, the endocytosis activity of PSMA-positive tumor cells towards conjugates Ab62-LP1, Ab62-LP2, Ab62-LP3, and the single-domain antibody Ab62 was determined, as shown in Figure 4. It can be seen that conjugation of different cargo-linkers did not affect the endocytosis of the single-domain antibody by PSMA-positive tumor cells.

Example 23: Preparation of Radionuclide Conjugate ⁶⁸ Ga-Ab62-LP1

The conjugate Ab62-LP1 (approximately 288 μg) was diluted in approximately 200 μL of 1 M NaOAc buffer (pH approximately 4.5), and a [ ⁶⁸ Ga]Ga ³⁺ solution (5 mCi, approximately 1 mL) was added to the system. The mixture was then incubated at 20-50°C for 10-120 minutes. The reaction solution was purified by SEC using a PD-10 desalting column and eluted with 0.01 M sterile PBS buffer (pH approximately 7.4), and the desired fractions were collected. The specific activity was approximately 0.01 mCi/μg, and the chemical purity and radioactive purity were determined by radio-HPLC. The results are shown in Figures 5 and 6, respectively.

Example 24: Preparation of Radionuclide Conjugate ¹⁷⁷ Lu-Ab62-LP1

Preparation 1: Dilute the conjugate Ab62-LP1 (approximately 200-1000 μg) in approximately 200-500 μL of 0.5 M _NH₄OAc buffer (pH approximately 4.0) and add [ ^⁻¹⁷Lu ]Lu⁻³ ⁺ solution (5-250 mCi). Incubate at 20-50°C for 10-120 minutes. Purify the reaction solution by SEC using a PD-10 desalting column and elute with 0.01 M sterile PBS buffer (pH approximately 7.4). Collect the desired fractions. The specific activity was approximately 10-150 mCi/mg. Chemical purity and radioactivity purity were determined by radio-HPLC. The results are shown in Figures 7 and 8, respectively.

Preparation 2: The conjugate Ab62-LP1 (approximately 300 μg) was diluted in approximately 500 μL of 1 M NaOAc buffer (pH approximately 4.5), and [ ¹⁷⁷ Lu]Lu ³⁺ solution (20-25 mCi) was added to the system. The mixture was then incubated at 20-50°C for 10-120 minutes. The reaction solution was purified by SEC using a PD-10 desalting column and eluted with 0.01 M sterile PBS buffer (pH approximately 7.4). The desired fractions were collected to obtain the conjugate ¹⁷⁷ Lu-Ab62-LP1, and an appropriate amount of NaVc solution (100 mg/mL) was added to the solution. The specific activity was approximately 0.04 mCi/μg. The chemical purity and radioactivity purity were determined by radio-HPLC, and the results are shown in Figures 9 and 10, respectively.

Example 25: Preparation of Radionuclide Conjugates ¹⁷⁷ Lu-Ab62-LP2, ¹⁷⁷ Lu-Ab62-LP3 and ¹⁷⁷ Lu-PSMA-617

Preparation 1: Referring to the method of Preparation 1 in Example 24, the conjugate Ab62-LP1 was replaced with conjugate Ab62-LP2, conjugate Ab62-LP3 and PSMA-617 (CAS: 1702967-37-0), respectively, to obtain conjugates ^177Lu -Ab62-LP2, ^177Lu -Ab62-LP3 and ^177Lu -PSMA-617, respectively. After purification, the chemical purity and radioactive purity were detected by radio-HPLC, both of which met the requirements of subsequent testing.

Preparation 2: Referring to the method of Preparation 2 in Example 24, the conjugate Ab62-LP1 was replaced with conjugate Ab62-LP2, conjugate Ab62-LP3 and PSMA-617 (CAS: 1702967-37-0), respectively, to obtain conjugates ^177Lu -Ab62-LP2, ^177Lu -Ab62-LP3 and ^177Lu -PSMA-617, respectively. After purification, the chemical purity and radioactive purity were detected by radio-HPLC, both of which met the requirements of subsequent testing.

Example 26: Serum Stability Test of Radionuclide Conjugates ¹⁷⁷ Lu-Ab62-LP1, ¹⁷⁷ Lu-Ab62-LP2, ¹⁷⁷ Lu-Ab62-LP3, and ¹⁷⁷ Lu-PSMA-617

20-50 μL of the radionuclide conjugates ^177Lu -Ab62-LP1, ^177Lu -Ab62-LP2, ^177Lu -Ab62-LP3, and ^177Lu -PSMA-617, prepared by the methods of Preparation 2 in Example 24 and Preparation 2 in Example 25, were added to an equal volume of mouse serum, pipetted and mixed thoroughly, and then incubated in a 37°C incubator. Samples were collected at 0, 8, and 24 hours of incubation for radioactive thin-layer chromatography analysis to determine the radioactivity purity of the system.

Test results showed that the radioactive purity of the radionuclide conjugate ^177Lu -PSMA-617 was 99.2% at 0h, slightly decreasing to 99.1% at 8h, but dropping to 97.0% at 24h. In contrast, the radioactive purity of the radionuclide conjugates ^177Lu -Ab62-LP1, ^177Lu -Ab62-LP2, and ^177Lu -Ab62-LP3 remained unchanged at 100% after incubation in serum for 0h, 8h, and 24h. Compared to the radionuclide conjugate ^177Lu -PSMA-617, the radionuclide conjugates ^177Lu -Ab62-LP1, ^177Lu -Ab62-LP2, and ^177Lu -Ab62-LP3 exhibited greater stability.

Example 27: Evaluation of In Vivo Antitumor Activity of Different ¹⁷⁷ Lu-Labeled Radionuclide Conjugates in PSMA ⁺ LNCaP Tumor-Bearing Mouse Model

The radionuclide conjugates ^177Lu -Ab62-LP1, ^177Lu -Ab62-LP2, ^177Lu -Ab62-LP3 (control 1) and the radionuclide conjugate ^177Lu -PSMA-617 (control 2) prepared by the methods of Preparation 2 in Example 24 and Preparation 2 in Example 25 were respectively injected into PSMA ⁺ LNCaP tumor-bearing mice, and the changes in tumor volume and body weight of the mice were recorded at different time points, as shown in the table below.

It can be seen that the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP2 showed the highest anti-tumor activity, and the activity of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP1 was also higher than that of the radionuclide conjugate ¹⁷⁷ Lu-Ab62-LP3 (control 1) and the radionuclide conjugate ¹⁷⁷ Lu-PSMA-617 (control 2).

The body weight of the mice subsequently recovered, indicating that the RDC of this application is safe and tolerable.

Example 28: Preparation of Radionuclide Conjugate ⁶⁴ Cu-Ab62-LP2

The conjugate Ab62-LP2 (approximately 100 μg) was diluted in approximately 200 μL of 1 M NaOAc buffer (pH approximately 4.5). [ ⁶⁴ Cu]Cu ²⁺ solution (6 mCi, approximately 300 μL) was added to the system and incubated at 20-50°C for 10-120 minutes. The reaction solution was purified by SEC using a PD-10 desalting column and eluted with 0.01 M sterile PBS buffer (pH approximately 7.4). The desired fractions were collected to obtain the radionuclide conjugate ⁶⁴ Cu-Ab62-LP2. The specific activity was approximately 0.19 mCi/μg. The chemical purity and radioactivity purity were determined by radio-HPLC, and the results are shown in Figures 11 and 12, respectively.

Example 29: Preparation of Radionuclide Conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP3 and ⁶⁴ Cu-PSMA-617

Referring to the method of Example 28, the conjugate Ab62-LP2 was replaced with the conjugate Ab62-LP1, the conjugate Ab62-LP3, and PSMA-617 (CAS: 1702967-37-0), respectively, to obtain radionuclide conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP3, and ⁶⁴ Cu-PSMA-617, respectively. After purification, the chemical purity and radioactive purity were both approximately 100% as determined by radio-HPLC.

Example 30: Stability of Radionuclide Conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, ⁶⁴ Cu-Ab62-LP3 and ⁶⁴ Cu-PSMA-617 in Mouse Serum

A certain amount of radionuclide conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, ⁶⁴ Cu-Ab62-LP3, and ⁶⁴ Cu-PSMA-617 were mixed and incubated with mouse serum, and samples were taken at 0 h, 8 h, and 24 h to detect the radiochemical purity of the samples using Radio-iTLC. The results are shown in Figure 13. It can be seen that compared with ⁶⁴ Cu-PSMA-617, the radionuclide conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, and ⁶⁴ Cu-Ab62-LP3 exhibited higher stability and almost no degradation.

Example 31: Uptake and Internalization of Radionuclide Conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, ⁶⁴ Cu-Ab62-LP3, and ⁶⁴ Cu-PSMA-617 in Tumor Cells

PSMA ⁺ LNCaP and PSMA- PC ^- 3 tumor cells were seeded into multiwell plates and allowed to adhere and grow overnight. The cells were washed with PBS, and a predetermined amount of culture medium was added to each well. Subsequently, the radionuclide conjugates ^64Cu -Ab62-LP1, ^64Cu -Ab62-LP2, ^64Cu -Ab62-LP3, and ^64Cu -PSMA-617 were added to each well, with duplicate wells for each sample. The samples were then diluted with saline and incubated for 4 hours. To test the uptake of the radionuclide conjugates by tumor cells, the cells were washed three times with ice-cold PBS, followed by addition of NaOH lysis buffer and measurement in a gamma counter. To test the internalization of each conjugate by tumor cells, the cells were first washed with ice-cold PBS, incubated in acidic buffer for 10 minutes, and then washed with ice-cold PBS. The samples were then added with NaOH lysis buffer and measured in a gamma counter. The results are shown in Figure 14 , which shows that the uptake and endocytosis activities of the three single-domain antibody radionuclide conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, and ⁶⁴ Cu-Ab62-LP3 in PSMA ⁺ LNCaP tumor cells were comparable to those of ⁶⁴ Cu-PSMA-617, and were hardly taken up by PSMA ^- PC-3 tumor cells.

Example 32: Positron Emission Tomography (PET) Imaging Study of Different ⁶⁴ Cu-Labeled Radionuclide Conjugates in PSMA ⁺ LNCaP Tumor-Bearing Mouse Model

Radionuclide conjugates ⁶⁴ Cu-Ab62-LP1, ⁶⁴ Cu-Ab62-LP2, ⁶⁴ Cu-Ab62-LP3 (control 3) and radionuclide conjugate ⁶⁴ Cu-PSMA-617 (control 4) were injected into PSMA ⁺ LNCaP tumor-bearing mice, respectively. The tumor-bearing mice were then scanned using PET/CT at different time points, and the corresponding images and the amount of ⁶⁴ Cu in tumors and key organ tissues were collected. The results are shown in the table below.

As can be seen, compared to ^64Cu -Ab62-LP3 (Control 3) and the conjugate ^64Cu -PSMA-617 (Control 4), ^64Cu -Ab62-LP1 and ^64Cu -Ab62-LP2 showed higher ^64Cu accumulation in tumors (AUC _1-48h ) and longer retention times. Furthermore, compared to the other three radionuclide conjugates, the ratio of ^64Cu accumulation in tumors to blood and key normal tissues for ^64Cu -Ab62-LP2 was significantly improved at both 24h and 48h.

Example 33: Preparation of conjugates Ab62-LP5, Ab62-LP6, Ab62-LP10 and Ab62-LP11

Referring to the preparation method of Example 18, compound LP1 was replaced with compound LP5, compound LP6, compound LP10, and compound LP11 to prepare conjugates Ab62-LP5, Ab62-LP6, Ab62-LP10, and Ab62-LP11, respectively. The resulting conjugates were further purified and subjected to DAR testing. The measured DAR values and purity analysis (monomer rate) results are shown in the following table:

Example 34: Preparation of Radionuclide Conjugates ⁶⁴ Cu-Ab62-LP5, ⁶⁴ Cu-Ab62-LP6, ⁶⁴ Cu-Ab62-LP10 and ⁶⁴ Cu-Ab62-LP11

Referring to the method of Example 28, the conjugate Ab62-LP2 was replaced with conjugates Ab62-LP5, Ab62-LP6, Ab62-LP10 and Ab62-LP11, respectively, to obtain radionuclide conjugates ⁶⁴ Cu-Ab62-LP5, ⁶⁴ Cu-Ab62-LP6, ⁶⁴ Cu-Ab62-LP10 and ⁶⁴ Cu-Ab62-LP11, respectively. After purification, the chemical purity and radioactive purity were both approximately 100% as determined by radio-HPLC.

Example 35: Positron Emission Tomography (PET) Imaging Study of Different ⁶⁴ Cu-Labeled Radionuclide Conjugates in PSMA ⁺ LNCaP Tumor-Bearing Mouse Model

The radionuclide conjugates ⁶⁴ Cu-Ab62-LP2, ⁶⁴ Cu-Ab62-LP5, ⁶⁴ Cu-Ab62-LP6, ⁶⁴ Cu-Ab62-LP10, and ⁶⁴ Cu-Ab62-LP11 were injected into PSMA ⁺ LNCaP tumor-bearing mice, respectively. The tumor-bearing mice were then scanned using PET/CT at different time points, and the corresponding images and the amount of ⁶⁴ Cu in tumors and key organ tissues were collected. The results are shown in the table below.

As can be seen, the radionuclide conjugates ⁶⁴ Cu-Ab62-LP5, ⁶⁴ Cu-Ab62-LP6, ⁶⁴ Cu-Ab62-LP10, and ⁶⁴ Cu-Ab62-LP11 all showed relatively high ⁶⁴ Cu accumulation (AUC) in tumors. In this tumor-bearing mouse model, from 1 to 72 hours after administration, the order of ⁶⁴ Cu accumulation in the blood was: ⁶⁴ Cu-Ab62-LP11 > ⁶⁴ Cu-Ab62-LP10 > ⁶⁴ Cu-Ab0362-LP5 > ⁶⁴ Cu-Ab0362-LP6. The order of ⁶⁴ Cu accumulation in tumors was identical to that in blood, and there was no significant difference in ⁶⁴ Cu accumulation in the kidneys among these four radionuclide conjugates.

Example 36: Preparation of a monoclonal single-domain antibody specifically targeting human epidermal growth factor receptor 2 (HER2)

36.1 Vector Construction and Expression

A monoclonal single-domain antibody with high affinity and specificity targeting human HER2 was selected, and its sequence is shown in the following table.

To generate an expression vector encoding an anti-human HER2 single-domain antibody, the nucleic acid sequence of the single-domain antibody was cloned into the pCDNA 3.4 vector; the cells were transformed into competent Escherichia coli cells via ligation, from which single clones were selected for sequencing confirmation. Positive clones were cultured and amplified for plasmid extraction to obtain a eukaryotic expression plasmid for the antibody, which was then transformed into Chinese hamster ovary cells (CHO cells) adapted to suspension growth by electroporation. After electroporation, the cells in the electroporated tubes were evenly distributed into shake flasks containing 100 ml of culture medium and incubated statically for 40 minutes. After incubation, the shake flasks were incubated at 37°C, 120 rpm, and 8% _CO2 to harvest the antibodies.

36.2 Antibody Purification

The antibody was purified by Ni affinity chromatography. First, 20 ml 1x PBS was used at a flow rate of 1 ml/min to equilibrate the column. After loading, the column was washed with 20 ml 1x PBS, 5 mM imidazole (pH 8.0) at a flow rate of 1 ml/min. The sample was then eluted with 150 mM imidazole (pH 8.0) at 1 ml/min and collected in separate tubes. The absorbance at 280 nm was read using a NanoDrop instrument. The high-concentration protein was transferred to a dialysis bag and placed in a beaker of 50 mM Tris + 150 mM NaCl, pH 8.0 for dialysis.

Example 37: Preparation of Conjugate Ab5-LP10

Referring to the preparation method of Example 18, compound LP1 was replaced with compound LP10, and single-domain antibody Ab62 was replaced with single-domain antibody Ab5 to prepare conjugate Ab5-LP10. The resulting conjugate was further purified and subjected to DAR testing. The measured DAR value and purity analysis (monomer rate) results are shown in the following table:

Example 38: Affinity detection (SPR method)

Referring to the method of Example 20, the human PSMA protein was replaced with the human HER2 protein, and the single-domain antibody Ab62 was replaced with the single-domain antibody Ab5, and their affinity strength was tested. The results are shown in the following table:

Example 39: Preparation of Radionuclide Conjugate ⁶⁴ Cu-Ab5-LP10

Referring to the preparation method of Example 28, the conjugate Ab62-LP2 was replaced with the conjugate Ab5-LP10 to prepare the radionuclide conjugate ⁶⁴ Cu-Ab5-LP10. After purification, the chemical purity and radioactivity purity were detected by radio-HPLC, and both met the requirements of subsequent tests.

Example 40: Positron Emission Tomography (PET) Imaging Study of ⁶⁴ Cu-Labeled Radionuclide Conjugates in the HER2 Highly Expressing Tumor-Bearing Mouse Model SKOV-3

The radionuclide conjugate ⁶⁴ Cu-Ab5-LP10 was injected into HER2-highly expressed SKOV-3 tumor-bearing mice. The tumor-bearing mice were then scanned using PET/CT at different time points. The corresponding images and the amount of ⁶⁴ Cu in the tumor and key organ tissues were collected. The results are shown in the table below.

It can be seen that, similar to ⁶⁴ Cu-Ab62-LP1 and ⁶⁴ Cu-Ab62-LP2 in Example 32, the radionuclide conjugate ⁶⁴ Cu-Ab5-LP10 has a high ⁶⁴ Cu accumulation in tumors (AUC _1-72h ) and a long retention time.

Example 41: Preparation of DLL3-targeted conjugates Ab12-LP10 and Ab9-LP5

Referring to the preparation method of Example 18, compound LP1 was replaced with compounds LP10 and LP5, and single-domain antibody Ab62 was replaced with anti-DLL3 single-domain antibody Ab12 and scFv fragment Ab9, respectively, to prepare conjugates Ab12-LP10 and Ab9-LP5. The resulting conjugates were further purified and subjected to DAR testing. The measured DAR values and purity analysis (monomer content) are shown in the table below. Ab9 is an scFv, and Ab12 is a VHH.

Example 42: Preparation of Radionuclide Conjugates ⁶⁴ Cu-Ab12-LP10 and ⁶⁴ Cu-Ab9-LP5

Referring to the preparation method of Example 28, the conjugate Ab62-LP2 was replaced with the targeted conjugates Ab12-LP10 and Ab9-LP5 to prepare radionuclide conjugates ⁶⁴ Cu-Ab12-LP10 and ⁶⁴ Cu-Ab9-LP5. After purification, the chemical purity and radioactive purity were detected by radio-HPLC, and both met the requirements of subsequent testing.

Example 43: Positron Emission Tomography (PET) Imaging Study of ⁶⁴ Cu-Labeled Radionuclide Conjugates in the DLL3-Expressing Tumor-Bearing Mouse Model H82

The radionuclide conjugate ⁶⁴ Cu-Ab12-LP10 was injected into DLL3-expressing H82 tumor-bearing mice. PET/CT scans of the tumor-bearing mice were then performed at different time points. The corresponding images and the amount of ⁶⁴ Cu in the tumor and key organ tissues were collected. The ratio of ⁶⁴ Cu in the tumor to that in the blood and muscle was calculated. The results are shown in the following table:

It can be seen that ⁶⁴ Cu-Ab12-LP10 can better enrich the tumor site.

Claims (74)

A radionuclide conjugate comprising the following structure:
in, is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling; Each Q is independently an albumin binding unit; Each D is independently a chelating group for a radionuclide; _La is connected to the targeting moiety and the coupling unit of G, each _La is independently selected from the following 1), 2) or a combination thereof: 1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, C _2-6 alkynyl, C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group; G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof: 3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; j is an integer selected from 1-30; k is an integer selected from 1-20; o is an integer or non-integer greater than 0 and less than 20. The radionuclide conjugate according to claim 1, wherein The targeting moiety Forming a covalent bond with the load unit by enzyme coupling; j is an integer selected from 1-10; k is an integer selected from 1-10; o is an integer greater than 0 and less than 10 or a non-integer. A radionuclide conjugate comprising the following structure:
in, is the targeting portion, and the rest is the loading unit, wherein the targeting portion Forming a covalent bond with the load unit by enzyme coupling or chemical coupling; Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit; Each D is independently a chelating group for a radionuclide; Each _La is independently selected from the following 1), 2) or a combination thereof: 1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 2) a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, C _2-6 alkynyl, C _3-10 cycloalkylene, 3-10 membered heterocycloalkylene, C _6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, sulfonyl-C _1-10 alkyl and 3-10 membered heterocycloalkyl; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group; Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20; Preferably, ^G1 and ^G3 are independently selected from a chemical bond or the following structures:
Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups: 1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl; Preferably, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,
The end of the wavy line with * is close to one end; n1 and n2 are each independently an integer from 0 to 10; j1, j2, k1, k2 are each independently an integer from 0 to 10; o is an integer greater than 0 and less than 10 or a non-integer. The radionuclide conjugate according to claim 3, wherein The targeting moiety Forming a covalent bond with the load unit by enzyme coupling; The PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-10; Preferably, ^G1 and ^G3 are independently selected from a chemical bond or the following structures:
Preferably, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof, The end of the wavy line with * is close to one end. The radionuclide conjugate according to any one of claims 1 to 4, wherein The targeting moiety is selected from a ligand, polypeptide, antibody or antigen-binding fragment thereof that specifically binds to the target; preferably, the targeting moiety is an antibody or an antigen-binding fragment thereof; more preferably, the targeting moiety Selected from single domain antibodies or single chain antibodies. The radionuclide conjugate according to any one of claims 1 to 5, wherein The targeting moiety These are anti-prostate-specific membrane antigen (PSMA) antibodies, anti-epidermal growth factor receptor 2 (HER2) antibodies, or anti-Delta-like ligand 3 (DLL3) antibodies. The radionuclide conjugate according to claim 6, wherein The targeting moiety comprising HCDR1 as shown in SEQ ID NO: 1, HCDR2 as shown in SEQ ID NO: 2, and HCDR3 as shown in SEQ ID NO: 3; or The targeting moiety comprising HCDR1 as shown in SEQ ID NO:4, HCDR2 as shown in SEQ ID NO:5 and HCDR3 as shown in SEQ ID NO:6; or The targeting moiety comprising HCDR1 as shown in SEQ ID NO:7, HCDR2 as shown in SEQ ID NO:8 and HCDR3 as shown in SEQ ID NO:9; or The targeting moiety It comprises HCDR1 as shown in SEQ ID NO: 23, HCDR2 as shown in SEQ ID NO: 24 and HCDR3 as shown in SEQ ID NO: 25. The radionuclide conjugate according to claim 6, wherein The targeting moiety comprising the amino acid sequence as shown in SEQ ID NO: 10 or SEQ ID NO: 11, or comprising the amino acid sequence as shown in positions 1 to 127 of SEQ ID NO: 12, or comprising the amino acid sequence as shown in positions 1 to 115 of SEQ ID NO: 22; or The targeting moiety An amino acid sequence that is at least 85% identical to the amino acid sequence shown in SEQ ID NO: 10 or SEQ ID NO: 11, or an amino acid sequence that is at least 85% identical to the amino acid sequence shown in positions 1 to 127 of SEQ ID NO: 12, or an amino acid sequence that is at least 85% identical to the amino acid sequence shown in positions 1 to 115 of SEQ ID NO: 22. The radionuclide conjugate according to any one of claims 1 to 4, wherein The targeting moiety The target unit is coupled to the target substance unit by enzyme coupling, and the enzyme used in the enzyme coupling is a ligase, and the ligase is selected from sortase, transglutaminase, formylglycine generating enzyme, tyrosinase and asparagine ligase; under the action of the ligase, the target portion _La forming the load unit by reacting with La _' ; Preferably, the targeting moiety Contains a ligase recognition substrate, and L _a' contains a ligase recognition substrate; preferably, the targeting portion Contains a ligase donor recognition substrate, L _a' contains a ligase receptor recognition substrate; preferably, L _a' contains a ligase donor recognition substrate, the targeting portion Contains a ligase receptor that recognizes a substrate. The radionuclide conjugate according to claim 9, wherein The targeting moiety The target unit forms a covalent bond with the load unit by enzyme coupling; under the action of the ligase, the target unit _La forming the load unit by reacting with La _' ; The ligase is a Sortase enzyme, and the targeting portion and La _' respectively comprise a Sortase enzyme donor substrate recognition sequence or an acceptor substrate sequence; preferably, the donor substrate recognition sequence is _LPX1TGX2 , _and the acceptor substrate recognition sequence is (Gly) _n , wherein _X1 is any natural or unnatural amino acid, _X2 is absent or is an amino acid fragment comprising 1-10 amino acids, and n is an integer of 2-20; or The ligase is transglutaminase, and the targeting moiety and La _' respectively comprise a transglutaminase donor substrate recognition structure or a transglutaminase acceptor substrate recognition structure; preferably, the La _' comprises -NH ₂ , the targeting moiety Contains glutamine; more preferably, said L _a' contains C _1-10 alkylene-NH ₂ or lysine; or The ligase is a formylglycine generating enzyme, and the targeting moiety and L _a' respectively comprise a formylglycine generating enzyme donor substrate recognition structure or a formylglycine generating enzyme acceptor substrate recognition structure; preferably, the L _a' comprises The wavy line indicates the site of connection with G or ^G1 or ^G2 of the loading unit, and the targeting moiety Containing the recognition sequence CX ₃ PX ₄ R, wherein X ₃ and X ₄ are any natural or unnatural amino acids; or The ligase is tyrosinase, and the targeting moiety and L _a' respectively comprise a tyrosinase donor substrate recognition structure or a tyrosinase acceptor substrate recognition structure; preferably, said L _a' comprises a bicyclo[6.1.0]nonyne structure, said targeting moiety contains tyrosine; or The ligase is asparagine ligase, and the targeting moiety and La _' respectively contain an asparagine ligase donor substrate recognition structure or an asparagine ligase acceptor substrate recognition structure; preferably, the asparagine ligase is Singzyme, the La _' contains an amino acid fragment GI, and the targeting moiety Contains a recognition sequence NX ₅ L, wherein X ₅ is any natural or unnatural amino acid; or, the asparagine ligase is butelase, the L _a' comprises an amino acid fragment GI, and the targeting moiety Contains the recognition sequence NHV. The radionuclide conjugate according to any one of claims 1 to 4, wherein The _La are each independently selected from the following structures: -(Gly) _n -, wherein n is an integer selected from 2 to 20, preferably an integer from 2 to 10, and more preferably 3; -NH-C _1-10 alkylene-(CO)-, preferably -NH-(CH ₂ ) ₄ -(CO)-. The radionuclide conjugate according to claim 1 or 2, wherein The G's are each independently selected from the following structures:

wherein g is an integer selected from 1-20, preferably an integer from 1-5; Further preferably,

Among them, the wavy line with * indicates the site connected to L _a , the wavy line with # indicates the site connected to L _c or L _b , and the wavy line indicates the site connected to L _b or L _c . The radionuclide conjugate according to claim 3, wherein When n2 is 0, ^G2 and ^G3 are absent, and ^G4 is selected from the following structural fragments,
When n2 is not 0, ^G2 and ^G4 are both the following structural fragments,
The wavy line with * indicates the site connected to ^G1 or ^G3 . The radionuclide conjugate according to any one of claims 1 to 4, wherein The L _b are each independently selected from the following structures: Chemical bonds; Among them, the wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 ; Wherein, the wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 or ^G4 ; or The wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . The radionuclide conjugate according to any one of claims 1 to 4, wherein The L _c is a chemical bond; or Among them, the wavy line with * indicates the site connected to Q, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . The radionuclide conjugate according to any one of claims 1 to 4, wherein The Q is a small molecule binder; preferably, the Q is independently selected from the following structures:
in, R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine; R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; Preferably, Q is each independently selected from The radionuclide conjugate according to any one of claims 1 to 4, wherein The D's are each independently selected from Bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl-(hydroxy)amino]- 4-oxobutyryl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo, [6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4 ,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane- 4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3 (1-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7- triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneamine tetraacetic acid (TMT), 1,4,7-triazacyclononane-1 ,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid and triethylenetetraaminehexaacetic acid (TTHA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide; Preferably, Each D is independently selected from 1,4,7,10-tetraazacyclododecane-N,N',N",N'-tetraacetic acid, 1,4,7-triazacyclononanetriacetic acid (NOTA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide. The radionuclide conjugate according to any one of claims 1 to 4, wherein The radionuclide is selected from any one radioactive cation or anion of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At and Er; Preferably, The radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; More preferably, The radionuclide is selected from ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu. The radionuclide conjugate according to claim 1, wherein The radionuclide conjugate comprises a structure selected from the group consisting of:



More preferably,


Among them, -S- and -GA-LPET- in the above structure are contained in the targeting part Part of the amino acids in. The radionuclide conjugate according to any one of claims 1 to 4, comprising the following formula (I'):
in, Q is the albumin binding unit; D and D' are each independently a chelating group for a radionuclide; A is a single-domain antibody or single-chain antibody, or an antigen-binding fragment thereof; Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-; Each of L ₁ , L ₂ , L ₁ ′ and L ₂ ′ is independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl; m is an integer selected from 0-20; n is an integer selected from 2 to 20; z is an integer selected from 1-20. The radionuclide conjugate according to claim 20, wherein The A terminal is modified and coupled with (Gly) _n in formula (I') under the action of ligase. The radionuclide conjugate according to claim 21, wherein The ligase is a Sortase enzyme; and/or A. An antibody comprising a C-terminal modification: an antibody, a spacer (SP), and a ligase donor substrate recognition sequence are sequentially linked, or an antibody and a ligase donor substrate recognition sequence are sequentially linked; and/or The SP is selected from GA, GGGGS, GGGGSGGGGS and GGGGSGGGGSGGGGS; and/or The ligase donor substrate recognition sequence is LPX ₁ TGX ₂ , wherein X ₁ is any natural or non-natural amino acid, and X ₂ does not exist or is an amino acid fragment containing 1-10 amino acids. The radionuclide conjugate according to any one of claims 20 to 22, wherein Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)- and -NH-(PEG) _i -(CO)-, wherein the (PEG) _i includes 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and a C _1-10 alkylene is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. The radionuclide conjugate according to any one of claims 20 to 22, wherein Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and a C 1-10 alkylene group is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O) _- structural unit; Preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; More preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-; More preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. The radionuclide conjugate according to any one of claims 20 to 22, wherein L ₁ and L _1' are each independently selected from any one of a chemical bond, a C _1-10 alkylene group, -NH- and -(CO)-, or any combination thereof; Preferably, L ₁ is selected from -(CH ₂ ) ₄ -NH-, -CO-NH-C ₂ H ₄ -NH- or -NH-; Preferably, L _1′ is selected from a chemical bond, —(CH ₂ ) ₄ —NH—, —CO—NH—C ₂ H ₄ —NH—, or —NH—. The radionuclide conjugate according to any one of claims 20 to 22, wherein L ₂ and L _2' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a C _1-10 alkylene group, and -NH-, or any combination thereof; Preferably, L ₂ is selected from -(CO)-, -(CH ₂ ) ₄ -NH-, -CO- an amino acid fragment with a degree of polymerization of 1-10 - or -CO-Lys-; Preferably, L _2' is selected from a chemical bond, -(CO)-, -(CH ₂ ) ₄ -NH-, -CO-, an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-. The radionuclide conjugate according to any one of claims 20 to 22, wherein m is an integer selected from 0-10, preferably, m is 0, 1 or 2; more preferably, it is 0 or 1; n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3; and/or When Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4; and/or z is an integer selected from 1-10, preferably, z is 1, 2, 3 or 4; more preferably, z is 1. The radionuclide conjugate according to any one of claims 20 to 22, wherein Said D and D' are each independently selected from bis (carboxymethyl) -1,4,8,11-tetraazabicyclo [6.6.2] hexadecane (CBTE2a), cyclohexyl -1,2-diaminetetraacetic acid (CDTA), 4- (1,4,8,11-tetraazacyclo tetradec-1-yl) -methylbenzoic acid (CPTA), N'- [5- [acetyl (hydroxy) amino] pentyl] -N- [5- [[4- [5-amino [4-Hydroxypentyl-(hydroxy)amino]-4-oxobutanoyl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane Heterocyclododecane-1,4,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetra Azacyclodecane-4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridinone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis (2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4 ,7-triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneaminetetraacetic acid) (TMT), 1,4,7-triazacyclononane -1,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid, and triethylenetetraaminehexaacetic acid (TTHA); Preferably, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid; D’ is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid. The radionuclide conjugate according to any one of claims 20 to 22, wherein The radionuclide is selected from any one radioactive cation or anion of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At and Er; Preferably, The radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At. The radionuclide conjugate according to any one of claims 20 to 22, wherein The Q is selected from
in, R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine; R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; Preferably, Q is selected from The radionuclide conjugate according to any one of claims 20 to 22, wherein A is an anti-prostate-specific membrane antigen (PSMA) antibody, an anti-epidermal growth factor receptor 2 (HER2) antibody, or an anti-Delta-like ligand 3 (DLL3) antibody. A compound comprising the following structure:
in, Each Q is independently an albumin binding unit; Each D is independently a chelating group for a radionuclide; L _a' is selected from the following 1), 2) or a combination thereof: 1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group; G is a branch portion having a branching function, directly or indirectly connected to Q and D; wherein each G is independently selected from the following 3), 4) or a combination thereof: 3) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 4) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; j is an integer selected from 1-30; k is an integer selected from 1-20. A compound comprising the following structure:
in, Each Q is independently an albumin binding unit; preferably, the albumin binding unit is a small molecule albumin binding unit; Each D is independently a chelating group for a radionuclide; Each L _a' is independently selected from the following 1), 2) or a combination thereof: 1) natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 2) _C1-20 alkyl, wherein the carbon chain units of the alkyl are optionally replaced by at least one substituent selected from -O-, -S-, -NH-, -(CO)-, _C2-6 alkynyl, _C3-10 cycloalkylene, _3-10 membered heterocycloalkylene, C6-10 arylene and 5-10 membered heteroarylene, wherein the alkylene, alkynyl, cycloalkylene, heterocycloalkylene, arylene and heteroarylene are optionally substituted by at least one substituent selected from hydroxy, halogen, amino, thiol, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amine, sulfonyl- _C1-10 alkyl and 3-10 membered heterocycloalkyl; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _{1-10 alkyl} group; Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20; Preferably, ^G1 and ^G3 are independently selected from a chemical bond or the following structures:
Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups: 1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent _{is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10 alkyl, C 1-10 alkoxy ,} amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl; Preferably, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,
The end of the wavy line with * is the end close to L _a' ; n1 and n2 are each independently an integer from 0 to 10; j1, j2, k1, and k2 are each independently an integer of 0-10. The compound according to claim 32 or 33, wherein L _a' is selected from the following structures: (Gly) _n , wherein n is an integer selected from 2-20, preferably an integer from 2-10, more preferably 3; C _1-10 alkyl-(CO)-, wherein the alkyl is substituted by an amino substituent; preferably NH ₂ -(CH ₂ ) ₄ -(CO)-. The compound according to claim 32, wherein The G is selected from the following structures:

wherein g is an integer selected from 1-20, preferably an integer from 1-5; Further preferably,

The wavy line with * indicates the site connected to L _a' , the wavy line with # indicates the site connected to L _c , and the wavy line indicates the site connected to L _b . The compound according to claim 33, wherein When n2 is 0, ^G2 and ^G3 are absent, and ^G4 is selected from the following structural fragments,
When n2 is not 0, ^G2 and ^G4 are both the following structural fragments,
The wavy line with * indicates the site connected to ^G1 or ^G3 . The compound according to claim 32 or 33, wherein The L _b are each independently selected from the following structures: Chemical bonds; Among them, the wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 ; Wherein, the wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 or ^G4 ; or The wavy line with * indicates the site connected to D, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . The compound according to claim 32 or 33, wherein The L _c is a chemical bond; or Among them, the wavy line with * indicates the site connected to Q, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . The compound according to claim 32 or 33, wherein The Q is a small molecule binder; preferably, the Q is independently selected from the following structures:

in, R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine; R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; Preferably, Q is selected from The compound according to claim 32 or 33, wherein The D's are each independently selected from Bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CBTE2a), cyclohexyl-1,2-diaminetetraacetic acid (CDTA), 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methylbenzoic acid (CPTA), N'-[5-[acetyl(hydroxy)amino]pentyl]-N-[5-[[4-[5-aminopentyl-(hydroxy)amino]- 4-oxobutyryl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo, [6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane-1,4 ,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10-tetraazacyclodecane- 4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-((bis(2-(3 (1-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1,4,7- triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneamine tetraacetic acid (TMT), 1,4,7-triazacyclononane-1 ,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid and triethylenetetraaminehexaacetic acid (TTHA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide; Preferably, Each D is independently selected from 1,4,7,10-tetraazacyclododecane-N,N',N",N'-tetraacetic acid, 1,4,7-triazacyclononanetriacetic acid (NOTA) and N ¹ -(5-aminopentyl)-N ¹ -hydroxy-N ⁴ -(5-(N-hydroxy-4-((5-(N-hydroxyacetamido)pentyl)amino)-4-oxobutanamido)pentyl)succinamide. The compound according to claim 32 or 33, wherein The radionuclide is selected from any one radioactive cation or anion of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At and Er; Preferably, The radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; More preferably, The radionuclide is selected from ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu. The compound according to claim 32 or 33, wherein The compound is selected from



More preferably,




A compound comprising the following structure:
in, Q is the albumin binding unit; D and D' are each independently a chelating group for a radionuclide; Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-; L ₁ , L ₂ , each of L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and C _1-10 alkyl; m is an integer selected from 0-20; n is an integer selected from 2-20. The compound according to claim 43, wherein Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)- and -NH-(PEG) _i -(CO)-, wherein the (PEG) _i includes 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and a C _1-10 alkylene is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. The compound of claim 44, wherein Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and a C 1-10 alkylene group is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O) _- structural unit; Preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; Preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-; more preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. The compound according to any one of claims 43 to 45, wherein L ₁ and L _1' are each independently selected from any one of a chemical bond, a C _1-10 alkylene group, -NH- and -(CO)-, or any combination thereof; Preferably, L ₁ is selected from -(CH ₂ ) ₄ -NH-, -CO-NH-C ₂ H ₄ -NH- or -NH-; Preferably, L _1′ is selected from a chemical bond, —(CH ₂ ) ₄ —NH—, —CO—NH—C ₂ H ₄ —NH—, or —NH—. The compound according to any one of claims 43 to 45, wherein L ₂ and L _2' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a C _1-10 alkylene group, and -NH-, or any combination thereof; Preferably, L ₂ is selected from -(CO)-, -(CH ₂ ) ₄ -NH-, -CO- an amino acid fragment with a degree of polymerization of 1-10 - or -CO-Lys-; Preferably, L _2' is selected from a chemical bond, -(CO)-, -(CH ₂ ) ₄ -NH-, -CO-, an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-. The compound according to any one of claims 43 to 45, wherein m is an integer selected from 0-10, preferably, m is 0, 1 or 2; more preferably, m is 0 or 1; n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3; and/or When Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. The compound according to any one of claims 43 to 45, wherein Said D and D' are each independently selected from bis (carboxymethyl) -1,4,8,11-tetraazabicyclo [6.6.2] hexadecane (CBTE2a), cyclohexyl -1,2-diaminetetraacetic acid (CDTA), 4- (1,4,8,11-tetraazacyclo tetradec-1-yl) -methylbenzoic acid (CPTA), N'- [5- [acetyl (hydroxy) amino] pentyl] -N- [5- [[4- [5-amino [4-Hydroxypentyl-(hydroxy)amino]-4-oxobutanoyl]amino]pentyl]-N-hydroxysuccinamide (DFO), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (DO2A), 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), α-(2-carboxyethyl)-1,4,7,10-tetraazacyclododecane Azacyclododecane-1,4,7,10-tetraacetic acid (DOTAGA), 1,4,7,10-azacyclododecane-N,N',N",N"'-1,4,7,10-tetra(methylene)phosphonic acid (DOTMP), N,N'-dipyridyloxyethylenediamine-N,N'-diacetic acid-5,5"-bis(phosphate) (DPDP), diethylenetriamine N,N',N"-penta(methylene)phosphonic acid (DTMP), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-tetraacetic acid (EDTA), ethylene glycol-O,O-bis(2-aminoethyl)-N,N,N",N"-tetraacetic acid (EGTA), N,N-bis(hydroxybenzyl)-ethylenediamine-N,N"-diacetic acid (HBED), hydroxyethylethylenediaminetriacetic acid (HEDTA), 1-(p-nitrobenzyl)-1,4,7,10- Tetraazacyclodecane-4,7,10-triacetate (HP-DOA3), 6-hydrazino-N-methylpyridine-3-carboxamide (HYNIC), tetrakis 3-hydroxy-N-methyl-2-pyridone chelating agent abbreviated as Me-3,2-HOPO (4-((4-(3-(bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)-2-(( Bis(2-(3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamido)ethyl)amino)methyl)propyl)phenyl)amino)-4-oxobutanoic acid), 1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1-(1-carboxy-3-carboxypropyl)-4,7-(carboxy)-1,4,7-triazacyclononane (NODAGA), 1, 4,7-Triazacyclononane triacetic acid (NOTA), 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (TE2A), 1,4,8,11-tetraazacyclododecane-1,4,8,11-tetraacetic acid (TETA), tris(hydroxypyridone) (THP), terpyridine-bis(methyleneamine tetraacetic acid (TMT), 1,4,7-triazacyclononane 1,4,7-tris[methylene(2-carboxyethyl)phosphinic acid] (TRAP), 1,4,7,10-tetraazacyclotridecane-N,N',N",N"'-tetraacetic acid (TRITA), 3-[[4,7-bis[[2-carboxyethyl(hydroxy)phosphoryl]methyl]-1,4,7-triazacyclononan-1-yl]methyl-hydroxy-phosphoryl]propionic acid, and triethylenetetraaminehexaacetic acid (TTHA) Preferably, D is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid; D’ is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid. The compound according to any one of claims 43 to 45, wherein The radionuclide is selected from any one radioactive cation or anion of F, Br, I, Sc, Cu, Ga, Y, In, Lu, Tc, Sm, Sr, Ra, Tb, Ho, Re, Pb, Bi, Ac, Th, Co, Gd, Dy, Zr, At and Er; Preferably, The radionuclide is selected from ¹⁸ F, ⁷⁷ Br, ¹³¹ I, ¹²⁵ I, ⁴³ Sc, ⁴⁴ Sc, ⁴⁷ Sc, ⁶⁴ Cu, ⁶⁷ Cu, ⁶⁷ Ga, ⁶⁸ Ga, ⁸⁶ Y, ⁹⁰ Y, ⁹⁰ In, ¹¹¹ In, ¹⁷⁷ Lu, ⁹⁴ Tc, ⁹⁹ Tc, ¹⁵³ Sm, ⁸⁹ Sr, ²²³ Ra, ¹⁵¹ Tb, ¹⁶⁶ Ho, ¹⁸⁶ Re, ¹⁸⁸ Re, ²¹² Pb, ²¹³ Bi, ²¹² Bi, ²²⁵ Ac, ²²⁷ Th, ⁵⁵ Co, ⁵⁷ Co, ¹⁵² Gd, ¹⁵³ Gd, ¹⁵⁷ Gd, ¹⁶⁶ Dy, ⁸⁹ Zr or ²¹¹ At; preferably ⁶⁸ Ga, ⁶⁴ Cu or ¹⁷⁷ Lu. The compound according to any one of claims 43 to 45, wherein The Q is selected from
in, R ¹ is selected from H, C _1-6 alkyl, halogen, methoxy, trifluoromethyl; preferably, R ¹ is selected from methyl or iodine; R ^a1 to R ^a11 are each independently selected from hydrogen, C _1-6 alkyl, C _1-6 alkoxy, halogen, cyano, nitro, amino or hydroxy; Preferably, Q is selected from A radionuclide conjugate comprising the following structure:
in, Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _1-10 alkyl group; G is a branch portion having a branching function, wherein G is selected from the following 1), 2) or a combination thereof: 1) one or more natural or unnatural amino acids or oligomeric natural or unnatural amino acids with a degree of polymerization of 2-20; 2) a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkyl group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; j is an integer selected from 1-30; k is an integer selected from 1-20. A radionuclide conjugate comprising the following structure:
in, Each L _b is covalently linked to a chelating group, and each L _c is covalently linked to an albumin binding unit; Each L _b and each L _c , when present, are independently a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -(CO)-, -NH-, -(C=S)-, C _6-10 arylene group, and a 5-10 membered heteroarylene group, wherein the alkylene group, arylene group, and heteroarylene group are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl group, C _1-10 alkoxy group, amine group, and sulfonyl-C _1-10 alkyl group; Each G ¹ or G ³ is independently selected from a chemical bond or a C _1-20 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, wherein the alkylene group is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl; preferably, each G ¹ or G ³ is independently selected from a chemical bond, optionally substituted -NH-(C _1-10 alkylene)-CO-, optionally substituted -NH-PEG-CO-, optionally substituted -NH-PEG-(C _1-10 alkylene)-CO-, optionally substituted -NH-(C _{1-10 alkylene)-PEG-CO-; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C 1-10} alkyl, C 1-10 alkoxy, amine and sulfonyl-C 1-10 alkyl. C _1-10 alkyl, C _1-10 alkoxy, amine and sulfonyl-C _1-10 alkyl-; the PEG is -(CH ₂ CH ₂ O) _x - or -(OCH ₂ CH ₂ ) _y -, where x or y is an integer of 1-20; Preferably, ^G1 and ^G3 are independently selected from a chemical bond or the following structures:
Each ^G2 or ^G4 is independently a branching unit when it occurs; preferably, it is selected from a combination of one or more of the following groups: 1) one or more branched natural or non-natural amino acid fragments; preferably, the branched natural or non-natural amino acid fragment has the following structure: -NH-(CR ² R ³ )-CO-, wherein R ² and R ³ are each independently selected from hydrogen, optionally substituted -(C _1-10 alkylene)-NH-, optionally substituted -(C _1-10 alkylene)-CO-; wherein R ² and R ³ are not hydrogen at the same time; more preferably, the branched natural or non-natural amino acid is a glutamic acid fragment, an aspartic acid fragment, or a lysine fragment; the substituted substituent is selected from hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl-; 2) C _1-20 straight or branched chain alkylene groups, wherein the carbon chain units of the alkylene groups are optionally replaced by at least one substituent selected from -O-, -NH-, and -(CO)-, wherein the alkylene groups are optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl; Preferably, ^G2 and ^G4 are each independently the following structural fragments or a combination thereof,
The end of the wavy line with * is the end close to G ¹ ; n1 and n2 are each independently an integer from 0 to 10; j1, j2, k1, and k2 are each independently an integer of 0-10. The radionuclide conjugate according to claim 52, wherein The G is selected from the following structures:
wherein g is an integer selected from 1-20, preferably an integer from 1-5; Further preferably,
Among them, the wavy line with # indicates the site connected to L _c or L _b , and the wavy line indicates the site connected to L _b or L _c . The radionuclide conjugate according to claim 53, wherein When n2 is 0, ^G2 does not exist, and ^G4 is selected from the following structural fragments:
When n2 is not 0, ^G2 and ^G4 are both the following structural fragments:
The wavy line with * indicates the site connected to ^G1 or ^G3 . The radionuclide conjugate according to claim 52 or 53, wherein The L _b are each independently selected from the following structures: Chemical bonds; Among them, the wavy line with * indicates the site of connection with the chelating group, and the wavy line indicates the site of connection with G, ^G2 , or ^G4 ; Wherein, the wavy line with * indicates the site of connection with the chelating group, and the wavy line indicates the site of connection with G, ^G2 or ^G4 ; or The wavy line with * indicates the site connected to the chelating group, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . The radionuclide conjugate according to claim 52 or 53, wherein The L _c is a chemical bond; or The wavy line with * indicates the site connected to the albumin binding unit, and the wavy line indicates the site connected to G, ^G2 , or ^G4 . A radionuclide conjugate comprising the following structure:
in, Ld is selected from a chemical bond or a C _1-60 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-; L ₁ , L ₂ , each L _1′ and L _2′ are each independently covalently linked to a chelating group or an albumin binding unit; wherein L ₁ , L ₂ , each L _1′ and L _2′ are each independently a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, or one or a combination thereof selected from the following divalent groups: C _1-10 alkylene, -NH- and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and C _1-10 alkyl; m is an integer selected from 0-20. The radionuclide conjugate according to claim 58, wherein Ld is selected from a chemical bond, -NH-C _1-20 alkylene-(CO)- and -NH-(PEG) _i -(CO)-, wherein the (PEG) _i includes 1-20 structural units selected from -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)-, and a C _1-10 alkylene is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural unit. The radionuclide conjugate according to claim 58, wherein Ld is -NH-(PEG) _i -(CO)-, wherein the (PEG) _i is 1-20 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and a C 1-10 alkylene group is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O) _- structural unit; Preferably, Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-; Preferably, Ld is -NH-PEG ₄ -C ₂ H ₄ -(CO)-; more preferably, Ld is -NH-(C ₂ H ₄ -O) ₄ -C ₂ H ₄ -(CO)-. The radionuclide conjugate according to any one of claims 58 to 60, wherein L ₁ and L _1' are each independently selected from any one of a chemical bond, a C _1-10 alkylene group, -NH- and -(CO)-, or any combination thereof; Preferably, L ₁ is selected from -(CH ₂ ) ₄ -NH-, -CO-NH-C ₂ H ₄ -NH- or -NH-; Preferably, L _1′ is selected from a chemical bond, —(CH ₂ ) ₄ —NH—, —CO—NH—C ₂ H ₄ —NH—, or —NH—. The radionuclide conjugate according to any one of claims 58 to 60, wherein L ₂ and L _2' are each independently selected from any one of a chemical bond, an amino acid fragment with a degree of polymerization of 1-10, -(CO)-, a C _1-10 alkylene group, and -NH-, or any combination thereof; Preferably, L ₂ is selected from -(CO)-, -(CH ₂ ) ₄ -NH- or -CO- an amino acid fragment with a degree of polymerization of 1-10 - or -CO-Lys-; preferably, L ₂ is -CO-Lys-; Preferably, L _2' is selected from a chemical bond, -(CO)-, -(CH ₂ ) ₄ -NH-, -CO-, an amino acid fragment with a degree of polymerization of 1-10, or -CO-Lys-; preferably, L _2' is -CO-Lys-. The radionuclide conjugate according to any one of claims 58 to 60, wherein m is an integer selected from 0-10, preferably, m is 0, 1 or 2; more preferably, it is 0 or 1; n is an integer selected from 2-10, preferably, n is 2, 3 or 4; more preferably, n is 3; and/or When Ld is -NH-(PEG) _i -C _1-10 alkylene-(CO)-, i is an integer selected from 1-12, preferably, i is 2, 3, 4, 5 or 6; more preferably, i is 4. A radionuclide conjugate comprising the following structure:
in, Ld' is selected from C _1-20 alkylene, wherein the carbon chain unit of the alkylene is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-; ^RA and ^RB are each independently optionally covalently linked to a chelating group and/or an albumin binding unit; wherein ^RA and ^RB are each independently selected from hydrogen or one or a combination of the following groups: _C1-10 alkylene, -NH-, and -(CO)-, wherein the alkylene is optionally substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano, and _C1-10 alkyl; wherein ^RA and ^RB are not simultaneously hydrogen; ^RC is optionally covalently linked to a chelating group, an albumin binding unit, or a combination thereof; wherein ^RC is selected from one or a combination of the following: a hydroxyl group, a natural or non-natural amino acid fragment, and a C _1-30 alkylene group, wherein the carbon chain unit of the alkylene group is optionally replaced by at least one substituent selected from -O-, -NR ⁴ -, -(CO)-, -(C=S)-, and a C _6-10 arylene group, and the alkyl and arylene groups are optionally substituted by at least one substituent selected from the group consisting of hydroxyl, halogen, amino, thiol, nitro, cyano, sulfonyl, C _1-10 alkyl, C _1-10 alkoxy, amine, and sulfonyl-C _1-10 alkyl; Said ^R4 is selected from hydrogen or _C1-10 alkyl, wherein the carbon chain unit of said alkyl is optionally replaced by at least one substituent selected from -O-, -NH- and -(CO)-, and said alkyl is optionally substituted by at least one substituent selected from hydroxyl, halogen, amino, mercapto, nitro, cyano, sulfonyl, _C1-10 alkyl, _C1-10 alkoxy, amino and sulfonyl- _C1-10 alkyl. The radionuclide conjugate according to claim 64, wherein Ld' is selected from -(PEG) _i - and C _1-10 alkylene, wherein the (PEG) _i is 1-10 consecutive -(OC ₂ H ₄ )- or -(C ₂ H ₄ -O)- structural units, and a C 1-10 alkylene is optionally connected to at least one end of the -(OC ₂ H ₄ )- or -(C ₂ H _{4 -O} )- structural unit; Preferably, Ld' is selected from -(C ₂ H ₄ -O) ₄ -C ₂ H ₄ - and C ₅ alkylene. The radionuclide conjugate according to claim 64, wherein ^RA and ^RB are each independently selected from hydrogen or _C1-10 alkylene, wherein the alkylene is substituted with at least one substituent selected from hydroxy, halogen, amino, nitro, cyano and _C1-10 alkyl; wherein ^RA and ^RB are not hydrogen at the same time; Preferably, ^RA and ^RB are each independently hydrogen and _C1-10 alkylene, wherein the alkylene is substituted by amino; wherein ^RA and ^RB are not hydrogen at the same time; More preferably, ^RA and ^RB are each independently hydrogen and The radionuclide conjugate according to claim 64, wherein R ^C is selected from hydroxyl, The radionuclide conjugate according to claim 64, wherein The formula (VII) is selected from the following structures:

Preferably,


Use of the radionuclide conjugate according to any one of claims 1 to 31, the compound according to any one of claims 32 to 51, or the radionuclide conjugate according to any one of claims 52 to 68 in the preparation of a radionuclide conjugate. A radionuclide conjugate comprising a radionuclide and the radionuclide conjugate according to any one of claims 1 to 31 or 52 to 68 or the compound according to claims 32 to 51. A pharmaceutical composition comprising the radionuclide conjugate according to claim 70, and optionally at least one pharmaceutically acceptable carrier. Use of the radionuclide conjugate according to any one of claims 1 to 31 or 52 to 68 or 70 or the pharmaceutical composition according to claim 71 for medical treatment and/or diagnosis. Use of the radionuclide conjugate of any one of claims 1 to 31 or 52 to 68 or 70 or the pharmaceutical composition of claim 72 in the preparation of a therapeutic or diagnostic nuclear medicine; The therapeutic nuclear medicine or diagnostic nuclear medicine is used to treat or diagnose malignant lymphoma, testicular seminoma, Wilms' tumor, neuroblastoma, medulloblastoma, Ewing sarcoma, small cell lung cancer, head and neck squamous cell carcinoma, esophageal squamous cell carcinoma, lung squamous cell carcinoma, breast cancer, cervical cancer, skin cancer, gastrointestinal adenocarcinoma, pancreatic cancer, prostate cancer, fibrosarcoma, liposarcoma or rhabdomyosarcoma. A method for diagnosing, delaying or treating a disease, comprising administering to a subject in need thereof an effective amount of the radionuclide conjugate of claim 1-31 or 52-68 or 70 or the pharmaceutical composition of claim 71; The diseases include malignant lymphoma, testicular seminoma, Wilms' tumor, neuroblastoma, medulloblastoma, Ewing sarcoma, small cell lung cancer, head and neck squamous cell carcinoma, esophageal squamous cell carcinoma, lung squamous cell carcinoma, breast cancer, cervical cancer, skin cancer, gastrointestinal adenocarcinoma, pancreatic cancer, prostate cancer, fibrosarcoma, liposarcoma or rhabdomyosarcoma.