WO2025224095A1

WO2025224095A1 - Use of inhibitors of il-6 or il-6r for treating graft versus host disease in a subject

Info

Publication number: WO2025224095A1
Application number: PCT/EP2025/060913
Authority: WO
Inventors: Emanuele AMMATUNA
Original assignee: Recordati Netherlands BV
Current assignee: Recordati Netherlands BV
Priority date: 2024-04-22
Filing date: 2025-04-22
Publication date: 2025-10-30
Anticipated expiration: 2026-10-22

Abstract

This invention relates to the use of inhibitors of IL-6 or IL-6R for treating graft-versus-host disease (GVHD) in a subject, including acute GVHD (aGVHD) or chronic GVHD (cGVHD). In particular, this invention relates to methods of treatment of GVHD in a subject in need thereof, wherein the treatment is a first-line treatment of GVHD, the method comprising a combination therapy of (i) administration to the subject of an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6 receptor; and (ii) administration to the subject of a corticosteroid; wherein the administration of the antibody or fragment is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

Description

USE OF INHIBITORS OF IL-6 OR IL-6R FOR TREATING GRAFT VERSUS HOST DISEASE IN A SUBJECT

REFERENCE TO A SEQUENCE LISTING

This application contains a Sequence Listing XML, which has been submitted electronically and is hereby incorporated by reference in its entirety.

FIELD

This invention relates to the use of inhibitors of IL-6 or IL-6R for treating graft-versus- host disease (GVHD) in a subject, including acute GVHD (aGVHD) or chronic GVHD (cGVHD). In particular, this invention relates to methods of treatment of GVHD in a subject in need thereof, wherein the treatment is a first-line treatment of GVHD, the method comprising a combination therapy of (i) administration to the subject of an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6 receptor; and (ii) administration to the subject of a corticosteroid; wherein the administration of the antibody or fragment is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

BACKGROUND

Graft-versus-host disease (GVHD) continues to be a major complication of allogeneic haematopoietic cell transplantation (HOT), including allogeneic haematopoietic stem cell transplantation (HSCT) and is associated with significant morbidity and mortality [1].

GVHD is a reaction of donor immune cells against host tissues: donor immune cells in the graft attack healthy cells in the patient (the host). GVHD can be acute (aGVHD) or chronic (cGHVD). aGVHD typically occurs within the first 10-100 days after transplantation, whereas cGVHD typically occurs more than 100 days after transplantation.

The three main tissues that aGVHD affects are the skin, liver and gastrointestinal tract. Certain risk factors, such as human leukocyte antigen mismatch, using unrelated donors, older patients and using female donor to male recipient, are usually associated with increased change of moderate to severe aGVHD. Despite more than five decades of research, there is no FDA-approved agent for frontline treatment of aGvHD and prednisone 2 mg/kg/day (or equivalent) is nearly universally used for grade II— IV aGvHD [2]. Response to standard frontline treatment (durable complete response [CR]) is <40% [3] and the patients who fail to respond to front line steroids experience an excessive mortality (>70%)> [4]. In particular, the outcomes in patients with steroid -refractory GVHD involving visceral organs is even worse as nearly all cases of severe GI GVHD are fatal [5]. For this reason more effective strategies are desirable.

There remains a need for further treatments of aGVHD to improve patient outcomes, avoid the toxicity of prolonged administration of steroids and, in turn, reduce the probability of relapse of the haematological disease and infections due to prolonged immunosuppression.

Interleukin (IL)-6 is an important, multifunctional, cytokine that regulates inflammatory response and immune reaction. It has been implicated in the physiology of numerous immune-mediated diseases. Biologic functions of IL-6 include critical roles in B- and T-cell differentiation as well as promoting recruitment and antiapoptosis of T lymphocytes [6]. IL-6 signaling also serves as an important mediator of immune cell trafficking to inflamed tissues and lymphoid organs [7]. Overproduction of IL-6 is pathologically involved in inflammatory autoimmune diseases such as rheumatoid arthritis (RA), juvenile idiopathic arthritis, and cytokine release syndrome after CAR-T cell therapy and therefore, blocking IL-6 activity is one of therapeutic options for these diseases. There are no known off-target effects.

Importantly, levels of IL-6 and IL-6 receptor (IL-6R) have been found to be increased in mice with GVHD, with the highest expression observed in the visceral organs (liver and gastro-intestinal tract) [8]. Blockade of IL-6 receptor signaling resulted in a reduction in GVHD-related mortality in murine models [9]. It resulted in a significant increased Treg levels in the spleen. In this model, the increased Treg levels were not dependent on an intact thymus; rather the IL-6 blockade increased peripheral generation of Treg cells and reduced the levels of the pro-inflammatory Th 1 and Th 17 cells [8].

Several reports describe testing of IL-6 or IL-6R inhibitors for the treatment of steroid refractory GVHD after HOT [10-13], i.e. only as a second-line treatment for GVHD itself. Clearly, identifying better treatment regimens for GVHD is a critical unmet need for allogeneic haematopoietic transplant recipients. All documents referred to herein are incorporated by reference in their entirety.

The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

SUMMARY

An object of the invention is to provide a treatment for graft-versus-host-disease in a subject in need thereof.

In a first aspect, the present invention provides a method of treatment of graft-versus- host disease in a subject in need thereof, wherein the treatment is a first-line treatment of graft-versus-host disease, the method comprising a combination therapy of: (i) administration to the subject of an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6 receptor; and (ii) administration to the subject of a corticosteroid; wherein the administration of the antibody or fragment is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

In a second aspect, the present invention provides an anti-IL-6 or anti-IL-6-receptor antibody or fragment for use in first-line treatment of graft-versus-host disease, wherein the first-line treatment comprises a combination therapy of administration of the antibody or fragment and administration of a corticosteroid, and wherein the administration of the antibody or fragment is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

In a third aspect, the present invention provides a use of an anti-IL-6 or anti-IL-6- receptor antibody or fragment in first-line treatment of graft-versus-host disease, wherein the first-line treatment comprises a combination therapy of administration of the antibody or fragment and administration of a corticosteroid, and wherein the administration of the antibody or fragment is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid. In a fourth aspect, the present invention provides a use of an anti-IL-6 or anti-IL-6- receptor antibody or fragment for the manufacture of a medicament for first-line treatment of graft-versus-host disease, wherein the medicament is to be administered in a combination therapy with administration of a corticosteroid, and wherein the administration of the medicament is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

The inventors have surprisingly found that blocking IL-6 signalling may be a potential therapeutic approach for first-line treatment of GVHD in patients, i.e. wherein antibody administration is in combination with corticosteroid administration and begins within the period 24 hours before or after initiation thereof.

DETAILED DESCRIPTION

As discussed above, there is an unmet need for improved treatments of GVHD in patients receiving allogeneic haematopoietic cell transplant, such as transplant of bone marrow or stem cells from a donor. The present invention relies on the use of IL-6 or IL-6R inhibitors, such as but not limited to Siltuximab (anti IL-6) or Tocilizumab (anti- IL-6R), to treat, inhibit, or block GVHD in such patients. These IL-6 or IL-6R inhibitors, such as Siltuximab or Tocilizumab, are to be used as a first-line treatment of GVHD in combination with corticosteroid administration. The GVHD can be aGVHD or cGVHD.

These and other aspects of the disclosure are described in detail below.

Unless indicated otherwise, all technical and scientific terms used herein will have their common meaning as understood by one of ordinary skill in the art to which this invention pertains.

It is contemplated that any method, use or treatment described herein can be implemented with respect to any other method, use or treatment described herein. All features disclosed herein in connection with any particular aspect are applicable to each of the other aspects, mutatis mutandis. In particular, all features disclosed herein in connection with the first aspect are applicable to each of the second to fourth aspects, mutatis mutandis. Other objects, features and advantages of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.

The term "comprises" or "comprising" will take its usual meaning in the art, namely indicating that the component includes but is not limited to the relevant features (i.e. including, among other things). As such, the term "comprises" will include references to the component consisting essentially of (such as consisting of) the relevant features. The term "consists of" or "consisting of" will take its usual meaning in the art, namely indicating that the component includes and is limited to the relevant features.

The use of the word "a" or "an" when used in conjunction with the term "comprising" in the claims and/or the specification may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one." The word "about" means plus or minus 5% of the stated number.

Where a numerical range is provided herein for any parameter, it is understood that all numerical subsets of that numerical range, and all the individual integer values contained therein, are provided as part of the invention.

As used herein, the term "optionally" means that the subsequently described event(s) may or may not occur, and includes both event(s) which occur, and events that do not occur.

Methods of Treatment

The first aspect of the invention is a method of treatment of graft-versus-host disease (GVHD) in a subject in need thereof, wherein the treatment is a first-line treatment of graft-versus-host disease, the method comprising a combination therapy of:

(i) administration to the subject of an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6 receptor (IL-6R); and

(ii) administration to the subject of a corticosteroid; wherein the administration of the antibody or fragment is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

The term "treatment", "treat" or "treating" as used herein, refers to therapeutic (curative) treatment including amelioration. Treatment also includes stopping the disease from developing or slowing further progression of the disease. For example, treatment may include preventing symptoms from worsening. The terms "prevention", "prevent" and "preventing" as used herein, refers to prophylaxis treatment i.e., action taken to prevent disease.

The terms "patient", "recipient" and "subject" are used interchangeably. By "a patient", "a subject" or "a recipient" we intend a human patient, subject or recipient. Typically the patient is an adult i.e. > 18 years old at the commencement of the treatment. Alternatively the patient may be a paediatric patient i.e. < 18 years old at the commencement of the treatment.

In a preferred embodiment of any of the aspects of the invention, the subject is a human.

By "first-line treatment of graft-versus-host disease", we include that the patient has not received a previous treatment for the GVHD before the combination therapy of the invention. Importantly, first-line treatment of GVHD is distinct from treatment of steroid -refractory GVHD, in which the existence of the status of being steroid refractory indicates that the patient has had a previous (unsuccessful) course of treatment of GVHD with corticosteroids. First-line treatment of GVHD indicates that the patient already exhibits symptoms of GVHD such that treatment of GVHD is deemed necessary, in contrast to prophylactic administration before a state of GVHD exists. For example, a maintenance level of immunosuppression may already have been administered as part of the overall medical procedures for the transplant, before the patient developed GVHD. Maintenance immunosuppressive therapy typically includes one or more of calcineurin inhibitors (cyclosporine and tacrolimus), mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus), antiproliferative agents (azathioprine and mycophenolic acid), co-stimulatory blockers (belatacept), and corticosteroids. The present invention relates to first-line treatment as the course of action prescribed as a result of the diagnosis of GVHD. This includes as a first-line treatment prescribed as a result of the diagnosis of aGVHD or as a result of the diagnosis of cGVHD.

In the context of this invention, "combination therapy" means that both (i) an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R; and (ii) a corticosteroid, are administered in combination as a treatment to the patient. By "in combination" we do not necessarily mean that the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R is administered at the same time as the corticosteroid. Nevertheless, the administration of the antibody or fragment is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid. After a first treatment dose of the antibody or fragment, the administration of any further treatment dose of the antibody of fragment may be independent of the administration of the corticosteroid, both in terms of length and timing of the treatment.

In a particular embodiment of any aspect of the invention, the subject has not previously received corticosteroid treatment for GVHD. Where the treatment is first- line treatment for aGVHD, this means that the subject has not previously received a course of corticosteroid treatment for aGVHD. Where the treatment is first-line treatment for cGVHD, this means that the subject has not previously received a course of corticosteroid treatment for cGVHD. As it is possible for a patient to experience aGVHD and, at a later point, develop cGVHD, the patient may still receive a first-line treatment for cGVHD once diagnosed, regardless of any corticosteroid treatment that may have been administered when the patient had aGVHD. For the avoidance of doubt, the present invention encompasses wherein the corticosteroid administration in the combination therapy is permitted to precede the administration of the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R by up to 24 hours; these nevertheless are a combination therapy.

By "first treatment dose", we include the first dose of a treatment to be given as part of the combination therapy. In some embodiments, the first treatment dose will be the only treatment dose of that component of the combination therapy, e.g. the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be given only once within the course of the combination therapy. In other embodiments, the first treatment dose will be the first of multiple treatment doses, such as the first of two doses, first of three doses, first of four doses etc.

Haematopoietic transplantation

In a particular embodiment of any aspect of the invention, the method is initiated after transplant of haematopoietic cells, haematopoetic stem cells, haematopoietic tissue, a haematopoetic organ, bone marrow or stem cells from a donor.

Hematopoietic stem cells (HSC) are cells in the blood-forming tissues that may give rise to all blood cell types and that may self-renew to produce more HSC. In mouse and human, HSC may represent up to 0.05% of cells in the bone marrow. Haematopoiesis is the process by which all mature blood cells are produced. The process balances enormous production needs (the average person produces more than 500 billion blood cells every day) with the need to regulate the number of each blood cell type in the circulation. In vertebrates, the vast majority of hematopoiesis occurs in the bone marrow and is derived from a limited number of hematopoietic stem cells that are multipotent and capable of extensive self-renewal.

Hematopoietic stem cells may give rise to different types of blood cells, in lines called myeloid and lymphoid. Myeloid and lymphoid lineages both are involved in dendritic cell formation. Myeloid cells include monocytes, macrophages, neutrophils, basophils, eosinophils, erythrocytes, and megakaryocytes to platelets. Lymphoid cells include T cells, B cells, natural killer cells, and innate lymphoid cells. Hematopoietic stem cells may be round, non-adherent, with a rounded nucleus and low cytoplasm-to-nucleus ratio. In shape, hematopoietic stem cells may resemble lymphocytes.

Hematopoietic stem cells are essential to haematopoiesis, which is the formation of the cells within blood. Hematopoietic stem cells can replenish all blood cell types (i.e., are multipotent) and self-renew. A small number of hematopoietic stem cells can expand to generate a very large number of daughter hematopoietic stem cells. This phenomenon is used in bone marrow transplantation, when a small number of hematopoietic stem cells reconstitute the hematopoietic system. This process indicates that, subsequent to bone marrow transplantation, symmetrical cell divisions into two daughter hematopoietic stem cells may occur. Stem cell self-renewal is thought to occur in the stem cell niche in the bone marrow.

Hematopoietic stem cells mostly exist in a state of quiescence, or reversible growth arrest. The altered metabolism of quiescent HSCs helps the cells survive for extended periods of time in the hypoxic bone marrow environment. When provoked by cell death or damage, Hematopoietic stem cells exit quiescence and begin actively dividing again. The transition from dormancy to propagation and back may be regulated by the MEK/ERK pathway and PI3K/AKT/mTOR pathway. Dysregulation of these transitions can lead to stem cell exhaustion, or the gradual loss of active Hematopoietic stem cells in the blood system.

Hematopoietic stem cells may be harvested directly from the blood.

Hematopoietic stem cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood. It may be autologous (the patient's own stem cells are used), allogeneic (the stem cells come from a donor) or syngeneic (from an identical twin). In the context of the present invention, the transplantation is allogeneic, leading to the possibility of GVHD.

Hematopoietic stem cell transplantation may be performed for patients with certain cancers of the blood or bone marrow, such as multiple myeloma or leukemia. In these cases, the recipient's immune system is usually destroyed with radiation or chemotherapy before the transplantation. Infection and graft-versus-host disease (acute or chronic) are potential major complications of allogeneic HSCT.

Stem cells may be used to regenerate different types of tissues. HCT is an established as therapy for chronic myeloid leukemia, acute lymphatic leukemia, aplastic anemia, and hemoglobinopathies, in addition to acute myeloid leukemia and primary immune deficiencies. Hematopoietic system regeneration is typically achieved within 2-4 weeks post-chemo- or irradiation therapy and HCT. HSCs are being clinically tested for their use in non-hematopoietic tissue regeneration.

Acute Graft-versus-Host Disease (aGVHD)

In a particular embodiment of any aspect of the invention, the method of treatment is of acute graft-versus-host disease (aGVHD) in a subject in need thereof.

"aGVHD" and "acute graft-versus-host disease" are used interchangeably throughout this document.

It will be appreciated that definitive, presumptive or possible diagnosis of aGVHD will be within the remit of the skilled practitioner.

Suitably, diagnosis of aGVHD may be in according to the Mount Sinai Acute GVHD International Consortium (MAGIC) criteria, which are reproduced in Table 3 in the Appendix herein. These criteria assess the condition of the skin, liver, upper gastrointestinal (GI) tract and lower GI tract.

In particular, the overall clinical grade may be based upon the most severe target organ involvement, as follows:

Grade 0: No stage 1-4 of any organ.

Grade I: Stage 1-2 skin without liver; Upper GI or lower GI involvement. Grade II: Stage 3 rash and/or stage 1 liver and/or stage 1 upper GI and/or stage 1 lower GI.

Grade III: Stage 2-3 liver and/or stage 2-3 lower GI, with stage 0-3 skin and/or stage 0-1 upper GI.

Grade IV: Stage 4 skin, liver or lower GI involvement, with stage 0-1 upper GI.

Measurement and determination of each of these criteria can be achieved by any appropriate method known in the art.

In a particular embodiment of any aspect of the invention, the acute graft-versus-host- disease is grade III or grade IV according to the Mount Sinai Acute GVHD International Consortium (MAGIC) criteria.

In a particular embodiment of any aspect of the invention, the administration of one or more treatment doses of the antibody or fragment in the combination therapy reduces the severity of one or more measures of aGVHD according to the MAGIC criteria. In a particular embodiment of any aspect of the invention, the administration of the first treatment dose of the antibody or fragment in the combination therapy reduces the severity of one or more measures of aGVHD according to the MAGIC criteria. In a particular embodiment of any aspect of the invention, the administration of a second treatment dose of the antibody or fragment in the combination therapy reduces the severity of one or more measures of aGVHD according to the MAGIC criteria.

The administration of one or more treatment doses of the antibody or fragment in the combination therapy may reduce one or more symptoms by one or more stages according to the MAGIC criteria. For example, the administration of one or more treatment doses of the antibody or fragment in the combination therapy may reduce one or more symptoms by one or more stages such that the overall clinical picture reduces by one or more grades according to the MAGIC criteria, e.g. from Grade IV to Grade III, Grade II, Grade I, or Grade 0, or from Grade III to Grade II, Grade I, or Grade 0.

The administration of the combination therapy may reduce one or more symptoms by one or more stages according to the MAGIC criteria. For example, the administration of the combination therapy may reduce one or more symptoms by one or more stages such that the overall clinical picture reduces by one or more grades according to the MAGIC criteria, e.g. from Grade IV to Grade III, Grade II, Grade I, or Grade 0, or from Grade III to Grade II, Grade I, or Grade 0.

Chronic Graft-versus-Host Disease

In a particular embodiment of any aspect of the invention, the method of treatment is of chronic graft-versus-host disease (cGVHD) in a subject in need thereof.

"cGVHD" and "chronic graft-versus-host-disease" (32, 33) are used interchangeably throughout this document. cGVHD may occur at any time after transplantation but typically develops at least 100 days after the transplantation. cGVHD may affect a single organ or multiple organs, lasting for years or up to a lifetime. An additional risk factor of cGVHD is the occurrence of prior aGVHD.

As used herein, the term "distinctive manifestation of cGVHD" refers to a sign or symptom of cGVHD that is not typically present in patients with aGVHD but is not sufficient to establish a diagnosis of cGVHD without further testing or additional organ involvement.

As used herein, the term "diagnostic manifestation of cGVHD" refers to a sign or symptom of cGVHD that is sufficient to establish the diagnosis of chronic GVHD.

In a particular embodiment of any aspect of the invention, the method is initiated at least 100 days after transplant of haematopoietic cells, haematopoetic stem cells, haematopoietic tissue, a haematopoetic organ, bone marrow or stem cells from a donor.

In a particular embodiment of any aspect of the invention, wherein the method of treatment is of cGVHD, the subject in need of treatment may have had prior aGVHD. In other embodiments of any aspect of the invention, the subject in need of treatment of cGVHD may not have had prior aGVHD.

In some embodiments wherein the method of treatment is of cGVHD, the subject in need of treatment presents at least one diagnostic manifestation of cGVHD or at least one distinctive manifestation of cGVHD confirmed by biopsy or testing of the same or other involved organ. It will be appreciated that definitive, presumptive or possible diagnosis of cGVHD will be within the remit of the skilled practitioner. Suitably, the at least one diagnostic manifestation or at least one distinctive manifestation of cGVHD may be found in the skin, mouth, GI tract, lung, nails, fascia and/or genitalia.

Suitably, the at least one diagnostic manifestation of cGVHD may be selected from the list comprising lichen planus-like features of the skin, sclerotic features of the skin, morphea-like features of the skin, lichen sclerosus-like features of the skin, lichen-type features of the mouth, hyperkeratotic plaques of the mouth, restriction of mouth opening from sclerosis, lichen planus-like features of the genitalia, vaginal scarring or stenosis of the genitalia, strictures or stenosis in the upper to mid third of the esophagus, bronchiolitis obliterans diagnosed with lung biopsy, fasciitis muscles, fascia and/joints, joint stiffness and/or contractures secondary to sclerosis of the muscles, fascia and/joints.

Suitably, the at least one distinctive manifestation of cGVHD may be selected from the list comprising depigmentation of the skin, dystrophy of the nails, longitudinal ridging, splitting and/or brittle features of the nails, onycholysis of the nails, pterygium unguis of the nails, nail loss, new onset of scarring or nonscarring scalp alopecia, scaling of the scalp, papulosquamous lesions, xerostomia, mucocele, oral ulcers, mucosal atrophy, pseudomembranes of the mouth, new onset of dry, gritty and/or painful eyes, cicatricial conjunctivitis, keratoconjunctivitis sicca, confluent areas of punctuate keratopathy, and/or erosions, fissures and/or ulcers of the genitalia.

Suitably, the confirmatory biopsy or testing of the same or other involved organ may be selected from the list comprising skin, mouth, lung, liver, GI and genital tissue biopsies, pulmonary function tests, Schirmer tests, or evaluation by a specialist such as an ophthalmologist or gynaecologist.

In a particular embodiment of any aspect of the invention, the administration of one or more treatment doses of the antibody or fragment in the combination therapy reduces the severity of, or eliminates, one or more symptoms of cGVHD. In a particular embodiment of any aspect of the invention, the administration of the first treatment dose of the antibody or fragment in the combination therapy reduces the severity of, or eliminates, one or more symptoms of cGVHD. In a particular embodiment of any aspect of the invention, the administration of a second treatment dose of the antibody or fragment in the combination therapy reduces the severity of, or eliminates, one or more symptoms of cGVHD. Antibodies and fragments thereof

By "antibody" we include substantially intact antibody molecules, as well as chimeric antibodies, humanised antibodies, human antibodies (wherein at least one amino acid is mutated relative to the naturally occurring human antibodies), single chain antibodies, bi-specific antibodies, antibody heavy chains, antibody light chains, homodimers and heterodimers of antibody heavy and/or light chains, and antigen binding fragments and derivatives of the same. The term also includes antibody-like molecules which may be produced using phage-display techniques or other random selection techniques for molecules. The term also includes all classes of antibodies, including IgG, IgA, IgM, IgD, and IgE. Also included for use in the invention are antibody fragments such as Fab, F(ab')2, Fv, Fab', scFv (single-chain variable fragment), or di- scFv and other fragments thereof that retain the antigen-binding site. Similarly, the term "antibody" includes genetically engineered derivatives of antibodies such as single-chain Fv molecules (scFv) and single-domain antibodies (dAbs).

In particular embodiments of any of the aspect of the invention, the antibody or fragment is a chimeric, humanized or CDR grafted antibody or fragment thereof.

Preferred antibodies are chimeric, such as mouse-human chimeric antibodies, CDR- grafted antibodies, humanised antibodies, or human antibodies. Although the antibody may be a polyclonal antibody, it is preferred if it is a monoclonal antibody, or that the antigen-binding fragment is derived from a monoclonal antibody. Suitable monoclonal antibodies may be prepared by known techniques, for example those disclosed in "Monoclonal Antibodies; A manual of techniques" (14) and in "Monoclonal Hybridoma Antibodies: Techniques and Application" (15). The antibodies may be human antibodies in the sense that they have the amino acid sequence of human antibodies with specificity for the IL-6 or the IL-6R; however, it will be appreciated that they may be prepared using methods known in the art that do not require immunisation of humans. Suitable antibodies may be prepared from transgenic mice which contain human immunoglobulin loci, as described in "Complete humanization of the mouse immunoglobulin loci enables efficient therapeutic antibody discovery" (16).

Suitably prepared non-human antibodies can be "humanised" in known ways, for example, by inserting the CDR regions of mouse antibodies into the framework of human antibodies. Chimeric antibodies are discussed in Neuberger et al (17). It will be appreciated by persons skilled in the art that the binding specificity of an antibody or antigen-binding fragment thereof is conferred by the presence of complementarity determining regions (CDRs) within the variable regions of the constituent heavy and light chains. As discussed below, in a particularly preferred embodiment of the antibodies and antigen-binding fragments, binding specificity for IL-6 is conferred by the presence of one or more and typically all six of the CDR amino acid sequences defined herein (i.e. the CDRs for siltuximab).

Preferably, the antibody or antigen-binding fragment comprises an antibody Fc region. It will be appreciated by the skilled person that the Fc portion may be from an IgG antibody, or from a different class of antibody (such as IgM, IgA, IgD, or IgE). For example, the Fc region may be from an IgGl, IgG2, IgG3, or IgG4 antibody. Advantageously, however, the Fc region is from an IgGl antibody. It is preferred that the antibody or antigen-binding fragment is an IgG molecule, or is an antigen-binding fragment or variant of an IgG molecule.

The antibody or fragment should be prepared under sterile conditions. The appropriate volume of antibody or fragment should be withdrawn from the vials. It is recommended that the antibody solution is filtered (0.2 to 1.2 pm) before injection into the patient either by using an in-line filter during infusion or by filtering the solution with a particle filter (e.g., filter Nr. MF1830, Impromediform, Germany). The volume of the antibody is typically added to an infusion bag containing 5% dextrose. Antibodies or fragments may be formulated in other ways, as known in the art.

IL-6 inhibitors

In some embodiments of any of the aspects of the invention, the antibody or fragment is capable of inhibiting human IL-6. In such embodiments, the antibody or fragment is an anti-IL-6 antibody or fragment.

By "IL-6" we include any natural or synthetic protein with structural and/or functional identity to the human IL-6 protein, such as defined in UniProt Accession No. P05231, or natural variants thereof. IL-6 gene and/or amino acid sequences are disclosed in references 18-20.

By "capable of inhibiting human IL-6" we intend that any antibody or fragment that can or may be able to bind to, inhibit, block or reduce human IL-6. IL-6 exerts its biological functions via two major pathways: classic signaling and trans-signaling pathways (21). In the classic signaling pathway, IL-6 binds to the IL-6 receptor (IL- 6R) on hepatocytes and some leukocytes. The IL-6 IL-6R complex further recruits the ubiquitously expressed membrane-bound or soluble gpl30 (sgpl30), triggering the dimerization of gpl30 and intracellular signaling. In the trans-signaling pathway IL-6 interacts with soluble IL-6R (sIL-6R) to form the IL-6 sIL-6R complex, which can bind to gpl30 on any cell and initiate intracellular signaling without a requirement for the stimulated cell to express IL-6R. An antibody which is capable of inhibiting human IL- 6 must be capable of specifically binding to human IL-6, and of inhibiting its interaction with sIL-6R or IL-6R, or otherwise preventing gpl30 activation. By "capable of specifically binding", we include the ability of the antibody or antigen-binding fragment to bind at least 10-fold more strongly to the relevant polypeptide, e.g. IL-6, than to any other polypeptide; preferably at least 50-fold more strongly and more preferably at least 100-fold more strongly. Inhibitory antibodies to IL-6 can typically be divided into two groups; and the putative epitopes on the IL-6 molecule designated Site I and Site II. Site I binders prevent binding to the IL-6R or sIL-6R and thereby prevent gpl30 activation. The Site I epitope was further characterized as comprising regions of both amino terminal and carboxy terminal portions of the IL-6 molecule. Site II- binders prevent gpl30 activation and therefore may recognize a conformational epitope involved in signalling. Binding of the antibody may be measured by surface plasmon resonance, for example, by immobilizing the antibody on a chip and using recombinant human IL-6 as analyte, as described in WO 2004/039826A1. Suitable antibodies may bind IL-6 with an affinity (Kd) of at least IO^-9 M, preferably at least 10’

¹⁰ M, preferably at least 10 ¹¹ or 5 x 10 ¹¹ M. Epitope mapping to identify Site I or Site

11 binders may be performed by binding to human IL-6-mutant proteins (22). Inhibition of IL-6 activity may be measured by assaying proliferation of the murine B myeloma cell line, 7TD1, in response to IL-6, as described in WO 2004/039826A1. Suitable antibodies may inhibit >50%, such as >90%, such as substantially 100% of 7TD1 cell proliferation in response to IL-6.

Suitable antibodies and fragments are described in WO 2004/039826A1. Suitably, the antibody or fragment which is capable of inhibiting human IL-6 is a chimeric, humanized or CDR grafted antibody or fragment thereof. Suitably, the antibody or fragment which is capable of inhibiting human IL-6 (also known as an anti-IL-6 antibody or fragment) is a chimeric, humanized or CDR grafted antibody or fragment thereof comprising a heavy chain variable region in which CDR1, CDR2, and CDR3 comprise the amino acid sequences SEQ ID NO: 1, SEQ ID NO: 2 and SEQ ID NO: 3, respectively; and a light-chain variable region in which CDR1, CDR2, and CDR3 comprise the amino acid sequences SEQ ID NO: 4, SEQ ID NO:, 5 and SEQ ID NO: 6, respectively, and a constant region derived from a human IgG antibody. VH CDR1 Ser Phe Ala Met Ser (SEQ ID NO. 1)

VH CDR2 Glu He Ser Ser Gly Gly Ser Tyr Thr Tyr Tyr Pro Asp Thr Vai Thr Gly (SEQ ID NO. 2)

VH CDR3 Gly Leu Trp Gly Tyr Tyr Ala Leu Asp Tyr (SEQ ID NO. 3)

VL CDR1 Ser Ala Ser Ser Ser Vai Ser Tyr Met Tyr (SEQ ID NO. 4)

VL CDR2 Asp Thr Ser Asn Leu Ala Ser (SEQ ID NO. 5)

VL CDR3 Gin Gin Trp Ser Gly Tyr Pro Tyr Thr (SEQ ID NO. 6)

In a preferred embodiment of any of the aspects of the invention, the anti-IL-6 antibody is siltuximab, or an antigen-binding fragment thereof. In a particularly preferred embodiment of any of the aspects of the invention, the antibody or fragment which is capable of inhibiting human IL-6 is siltuximab. Siltuximab, also known as CNTO328 and CLLB8, with the US FDA UNII Identifier T4H8FMA7IM and the WHO ATC code L04AC11 is a chimeric (human-murine) IgGlK monoclonal antibody that binds to human IL-6. The intact molecule contains 1324 amino acid residues and is composed of two identical heavy chains (approximately 50 kDa each) and two identical light chains (approximately 24 kDa each) linked by inter-chain disulfide bonds. Siltuximab contains the antigen-binding variable region of the murine antibody, CLB-IL-6-8, and the constant region of a human IgGlK immunoglobulin.

The complete amino acid sequences of the heavy and light chains of siltuximab are shown below.

SEQ ID NO. 7 Siltuximab heavy chain amino acid sequence

EVQLVESGGKLLKPGGSLKLSCAASGFTFSSFAMSWFRQSPEKRLEWVAEI SSGGSYTYY PDTVTGRFT I S RDNAKNTLYLEMS S LRS EDTAMYYCARGLWGYYALDYWGQGT S VTVS SA STKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSG LYSLSSWTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGP SVFLFPPKPKDTLMI SRTPEVTCVWDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNS TYRWSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTI SKAKGQPREPQVYTLPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSCSVMHEALHNHYTQKSLSLSPGK

SEQ ID NO. 8 Siltuximab light chain amino acid sequence

QIVLIQSPAIMSASPGEKVTMTCSASSSVSYMYWYQQKPGSSPRLLIYDTSNLASGVPVR

FSGSGSGTSYSLTI SRMEAEDAATYYCQQWSGYPYTFGGGTKLEIKRTVAAPSVFI FPPS DEQLKSGTASWCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTL

S KADYEKHKVYACEVTHQGLS S PVTKS FNRGEC

Siltuximab and methods of preparing it, including by recombinant expression of encoding nucleic acid sequences, are described in WO 2004/039826A1.

Siltuximab is a humanized monoclonal antibody (IgGl) and a human interleukin-6 (IL-6) receptor antagonist. Siltuximab is licensed by the EMA and FDA for the treatment of patients with rheumatoid arthritis, idiopathic multicentric Castleman's disease (iMCD), and cytokine release syndrome in the setting of chimeric antigen receptor T-cell (CAR-T) therapy.

Siltuximab has not previously been used in combination with corticosteroid administration as a first-line treatment of aGVHD or cGVHD.

Other suitable antibodies include olokizumab, which is a IgG4K antibody humanized from rat (23); elsilimomab (also known as B-E8), which is a mouse IgGlK monoclonal antibody (24); or the human monoclonal antibody clone 1339, which is a high-affinity fully humanized anti-IL-6 monoclonal antibody (IgGl) derived from elsilimomab (25). Further suitable antibodies include clazakizumab (formerly ALD518 and BMS-945429), which is an aglycosylated, humanized rabbit IgGl monoclonal antibody against interleukin-6 (26); sirukumab, which is a human monoclonal IgGl kappa antibody (27). Further suitable antibodies include: the MH166 antibody (28); the SK2 antibody (29); Levilimab, which is an anti IL-6 monoclonal antibody initially developed to treat rheumatoid arthritis (30); and ARGX-109, which is a preclinical stage human antibody candidate developed by arGEN-X from its SIMPLE Antibody™ platform and which is said to have outstanding neutralization potency for IL-6. Fragments of any of these antibodies may also be used.

The antibody or fragment should be prepared under sterile conditions. The appropriate volume of antibody or fragment should be withdrawn from the vials. It is recommended that the antibody solution is filtered (0.2 to 1.2 pm) before injection into the patient either by using an in-line filter during infusion or by filtering the solution with a particle filter (e.g., filter Nr. MF1830, Impromediform, Germany). The volume of the antibody is typically added to an infusion bag containing 5% dextrose. Siltuximab is available as a single-use vial containing 100 mg or 400 mg siltuximab powder for concentrate for solution for infusion, and should be stored at refrigeration temperature. The siltuximab powder is typically provided with one or more excipients, typically histidine, histidine hydrochloride monohydrate, polysorbate 80, and sucrose. After reconstitution with single-use sterile water for injection, the solution contains 20 mg siltuximab per mL. Antibodies or fragments may be formulated in other ways, as known in the art.

The dose of the anti-IL-6 antibody when administered by intravenous administration, such as by infusion, may be 11 ± 3 mg/kg subject body weight, optionally 11 mg/kg. A suitable dose of the fragment is a dose having an equivalent antagonistic effect on human IL-6.

IL-6R inhibitors

In some embodiments of any of the aspects of the invention, the antibody or fragment is capable of inhibiting human IL-6 receptor (IL-6R). In such embodiments, the antibody or fragment is an anti-IL-6R antibody or fragment.

By "IL-6R" we include any natural or synthetic protein with structural and/or functional identity to the human IL-6R protein, such as defined in UniProt Accession No. P08887, or natural variants thereof. IL-6R gene and/or amino acid sequences are disclosed in US 10323095 B2. In particular, SEQ ID NOs. 8 and 9 of US 10323095 B2 disclose the Tocilizumab heavy chain sequence (SEQ ID NO 8 of US 10323095 B2) and Tocilizumab light chain sequence (SEQ ID NO 9 of US 10323095 B2). We also include soluble isoforms of the IL-6R, such as produced by alternative splicing or limited proteolysis by ADAMO and ADAM 17. Inhibition of IL-6R activity may be measured by assaying BaF/gpl30 proliferation in the presence of IL-6, as described in US 2011076275 Al.

By "capable of inhibiting human IL-6R" we intend that any antibody or fragment that can or may be able to bind to, inhibit, block or reduce human IL-6R of sIL-6R. An antibody which is capable of inhibiting human IL-6R must be capable of specifically binding to human IL-6R, and of inhibiting its interaction with IL-6, or otherwise preventing gpl30 activation. Binding of the antibody may be measured by surface plasmon resonance. Suitable antibodies may bind IL-6R with an affinity (Kd) of at least IO^-9 M, preferably at least 10 ¹⁰ M, preferably at least 10 ¹¹ or 5 x 10 ¹¹ M. The skilled person would understand how to measure inhibition of IL-6R activity by any suitable technique known in the art.

Suitably, the antibody or fragment which is capable of inhibiting human IL-6R is a chimeric, humanized or CDR grafted antibody or fragment thereof. In particular embodiments of any of the aspects of the invention, the antibody or fragment which is capable of inhibiting human IL-6R is tocilizumab or sarilumab.

Sarilumab is a fully human anti-interleukin 6 receptor (IL-6R) monoclonal IgGl antibody that binds to both membrane-bound and soluble IL-6 receptor forms, thus blocking the cis- and trans-inflammatory signalling cascades of IL-6. Sarilumab has been approved by the FDA for the treatment of moderate to severe rheumatoid arthritis (RA) in combination with methotrexate.

Tocilizumab is a humanized monoclonal antibody against IL-6R, which binds to both soluble and membrane-bound IL-6Rs with a Kd of ~ 2.54 nM (31). It blocks IL-6 induced signal transduction pathways through competitive inhibition of IL-6 binding to its receptors, and has been approved in Japan for treatment of Castleman's disease (21).

The dose of the anti-IL-6R antibody when administered by intravenous administration, such as by infusion, may be 6 ± 4 mg/kg subject body weight, optionally 4 mg/kg or 8 mg/kg. A suitable dose of the fragment is a dose having an equivalent antagonistic effect on human IL-6R.

Immunosuppressive Therapy

By "immunosuppressive therapy" we include the standard, routine, common immunosuppressive therapies which are given to transplant recipients before, after or during the transplant procedure to suppress their immune system and reduce the risk of the recipient's body rejecting the transplant. The purpose is to stop an unwanted immune response that would damage survival of the transplanted tissue and/or of the subject. Some transplant recipients may be on a life-long immunosuppressive treatment regimen after the transplant. Some patients may be able to reduce or stop taking certain immunosuppressive therapies (e.g., corticosteroids) after the transplant, which may reduce the risk of the side effects and complications associated with the immunosuppressive therapies. This is particularly because continuation of immunosuppressive therapies may result in immunodeficiency, by which the subject may be susceptible to opportunistic infection and/or increase the likelihood of cancer due to reduced surveillance of damaged cells by the immune system. Some common immunosuppressive therapy options administered to patients after a transplant include glucocorticoids (corticosteroids), monoclonal antibodies (mAbs), nucleotide blocking agents, calcineurin inhibitors, and mTOR inhibitors; typically a combination of such agents is used. Suitable immunosuppressive therapy options are known to the person skilled in the art.

Immunosuppressive therapies may be categorised as induction agents, maintenance therapy, or rescue therapy. Induction agents are administered at the time of transplant and are generally more powerful immunosuppressive agents; for this reason they are given for a short acute period. Maintenance therapy comprises medications used over a longer period; it is usually used as a form of therapy to be administered chronically to ensure and improve tolerance and continued acceptance of the recipient organ or graft. Rescue therapy is given when clinical signs of rejection require additional action, such as when the transplant rejection becomes refractory to other medications.

Corticosteroids

The present invention requires corticosteroid administration as part of the combination therapy in the first-line treatment of GVHD.

Corticosteroids are an important part of the arsenal of available immunosuppressive therapies. They are anti-inflammatory medicines. Corticosteroids may be a manmade version of hormones normally produced by the adrenal glands. By corticosteroids we particularly mean glucocorticoids or glucocorticosteroids. Glucocorticoids are steroid hormones produced from the cortex of adrenal glands. Glucocorticoids have a pivotal role in the glucose, protein, and fat metabolism of the body. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebrate animal cell.

It will be appreciated by the skilled person that corticosteroids, including glucocorticoids or glucocorticosteroids, are widely known immunosuppressive therapies.

Suitably, in any of the aspects of the invention, the corticosteroid may be one or more of prednisolone, prednisone, methylprednisolone, cortisone, dexamethasone, betamethasone and hydrocortisone. In particularly embodiments of any of the aspects of the invention, the corticosteroid comprises or consists of prednisolone. The corticosteroid may be administered in any suitable dose, for example in accordance with usual dosing for immunosuppression or treatment of GVHD, i.e. aGVHD or cGVHD.

In a particular embodiment of any of the aspects of the invention, the corticosteroid comprises or consists of prednisolone administered at a dose of 2 mg/kg/day.

The skilled person would be able to design a suitable treatment plan using corticosteroids. The treatment plan may be revised during the treatment as the patient requires. It will be appreciated that immunosuppressive treatment may be reduced at some point during treatment to reduce the risk of becoming immunodeficient, which could lead to opportunistic infection or reduced cancer surveillance. In the context of the present invention, reduction of corticosteroid dose compared to the starting dose at the beginning of the first-line treatment of GVHD is particularly envisaged. The decision to reduce dosage is typically contingent on the subject's response to the combination therapy.

In a particular embodiment of any of the aspects of the invention, the corticosteroid dose is tapered from day 7 onwards according to response to the therapy, wherein day 1 is the day of the first treatment dose of the antibody or fragment.

As a non-limiting example, tapering of a dose of 2 mg/kg/day prednisolone may be determined as follows, depending on whether the patient has complete remission (OR), very good partial remission (VGPR) or partial remission (PR):

1. OR: reduce prednisolone to 1 mg/kg and thereafter the prednisolone with 10% every 3 days.

2. VGPR or PR: reduce prednisolone 10% every 5 days.

As another non-limiting example, tapering of a dose of 2 mg/kg/day prednisolone may be determined as follows, depending on whether the patient has complete remission (OR), very good partial remission (VGPR) or partial remission (PR):

1. VGPR or OR: reduce prednisolone to 1 mg/kg and thereafter the prednisolone with 10% every 3 days.

2. PR: reduce prednisolone 10% every 5 days.

Administration of the Combination Therapy The antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be administered via the same or a different administration route as the corticosteroid and/or any other immunosuppressive compound(s). In one embodiment, the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be prepared e.g. for parenteral administration e.g., subcutaneous, intramuscular, intravenous, intra-dermal, intra-articular or peri-articular administration, particularly in the form of liquid solutions or suspensions; or for inhalation to the lungs e.g. pulmonary administration, particularly in the form of solutions, suspensions including nanosuspensions for nebulisation, or suspension or solution pressurised or non-pressurised aerosols. The corticosteroid and any other immunosuppressive compound(s) may be prepared e.g. for parenteral administration e.g., subcutaneous, intramuscular, intravenous, intra-dermal, intra-articular or periarticular administration, particularly in the form of liquid solutions or suspensions; for oral administration, particularly in the form of tablets, capsules, powder, granules, solid dispersions or in the form of liquid solutions or suspensions including nanosuspensions; for inhalation to the lungs or nose e.g. pulmonary or intranasal administration, particularly in the form of dry powders, solutions, suspensions including nanosuspensions for nebulisation, nasal sprays or drops comprising solutions or suspensions or suspension or solution pressurised or non-pressurised aerosols; for topical or transdermal administration e.g. as creams, sprays, foams, gels, ointments, liquids, patches; for mucosal administration e.g. to buccal, sublingual or vaginal mucosa, and for rectal administration e.g. in the form of a foam or suppository.

The antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R, and/or the corticosteroid and/or any other immunosuppressive compound(s) may be administered by inhalation. An advantage of inhaled medications is their direct delivery to the area of rich blood supply in comparison to many medications taken by oral route. Thus, the absorption is very rapid as the alveoli have an enormous surface area and rich blood supply and first pass metabolism is bypassed.

The antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R, and/or the corticosteroid and/or any other immunosuppressive compound(s) may conveniently be administered in unit dosage form and may be prepared by any of the methods well-known in the pharmaceutical art. The antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R, and/or the corticosteroid and/or any other immunosuppressive compound(s) may also conveniently be administered in multiple unit dosage form. The present invention also provides an inhalation device containing the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R, and/or the corticosteroid and/or any other immunosuppressive compound(s) of the present invention. Typically said device is a metered dose inhaler (MDI), which contains a pharmaceutically acceptable chemical propellant to push the medication out of the inhaler.

The corticosteroid and/or any other immunosuppressive compound(s) may be administered by intranasal administration. The nasal cavity's highly permeable tissue is very receptive to medication and absorbs it quickly and efficiently. Nasal drug delivery is less painful and invasive than injections, generating less anxiety among patients. By this method absorption is very rapid and first pass metabolism is usually bypassed, thus reducing inter-patient variability.

The corticosteroid and/or any other immunosuppressive compound(s) may be administered by transdermal administration. For topical delivery, transdermal and transmucosal patches, creams, ointments, jellies, solutions or suspensions may be employed.

The corticosteroid and/or any other immunosuppressive compound(s) may also be administered by sublingual administration.

In a preferred embodiment of any of the aspects of the invention, the administration to the subject of the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R is by intravenous administration, optionally by infusion, optionally wherein the infusion is over the course of one hour.

The present disclosure provides pharmaceutical compositions comprising IL-6 or IL-6R inhibitors, pharmaceutical compositions comprising a corticosteroid and pharmaceutical compositions comprising one or more additional immunosuppressant compounds. Such compositions may comprise a prophylactically or therapeutically effective amount of the active drug (the IL-6 or IL-6R inhibitor, corticosteroid and/or one or more additional immunosuppressant compounds), and a pharmaceutically acceptable carrier. In a specific embodiment, the term "pharmaceutically acceptable" means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans. The term "carrier" refers to a diluent, excipient, or vehicle with which the therapeutic is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Water is a particular carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Other suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like.

The various compositions in the context of the therapies and administrations described herein, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations and the like. Oral formulations can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical agents are described in "Remington's Pharmaceutical Sciences." Such compositions will contain a prophylactically or therapeutically effective amount of the agent, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration, which can be oral, intravenous, intraarterial, intrabuccal, intranasal, nebulized, bronchial inhalation, intra-rectal, vaginal, topical or delivered by mechanical ventilation.

Pharmaceutically acceptable salts include the acid salts and those which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed with the free carboxyl groups may also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the like.

Generally, the ingredients of compositions of the disclosure are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water-free concentrate in a hermetically sealed container such as an ampoule or sachette indicating the quantity of active agent. Where the composition is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the composition is administered by injection, an ampoule of sterile water for injection or saline can be provided so that the ingredients may be mixed prior to administration.

A person skilled in the art would be aware of the appropriate administration routes for different therapies. For example, the administration route may vary inter alia according to patient characteristics, dosage amount(s) and/or frequency, and/or the type of therapy. Further, the administration route (technique) may be different across different therapies within the regimen.

The antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be administered according to a dosage regimen. For instance, the administration may include one or more (including two or more, three or more, four or more) doses of the antibody or fragment. For example, the administration may comprise one, two, three, four, five, six, seven, eight, nine or more doses to a subject of the antibody or fragment. Preferably, the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R is administered as 1 or 2 doses. For example, the antibody or fragment which is capable of inhibiting human IL-6 or IL-6R may be administered as a single dose on day 1 without any subsequent doses in the context of the treatment of GVHD.

In particular embodiment of any aspect of the invention, a second treatment dose of the antibody or fragment is given after the first treatment dose, if clinically indicated.

For example, the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be administered as 2 doses, a first dose on day 1 and a second dose on a subsequent day if clinically indicated.

By "clinically indicated" in this context, we include the reason that the GVHD (such as aGVHD) is at the same stage or has partial remission when assessed on a different day to the administration of the first treatment dose of the antibody or fragment. For example, the assessment may be made on day 3 wherein day 1 is the day of the first treatment dose of the antibody or fragment, or when assessed between 36 and 60 hours after the first treatment dose of the antibody or fragment.

In a particular embodiment of any aspect of the invention, administration of a second treatment dose of the antibody or fragment, such as when clinically indicated, may be administered on day 3 wherein day 1 is the day of the first treatment dose of the antibody or fragment, or may be administered between 36 and 60 hours after the first treatment dose of the antibody or fragment.

The dose of the antibody or fragment is determined according to the weight in kg of the patient. Where a dose is given in the units of "mg/kg", this refers to mg of antibody or fragment or other drug per kg of body weight of the patient. An antibody fragment is to be administered at an equivalent fragment dose having an equivalent antagonistic effect on human IL-6 (or human IL-6R, respectively) to the whole antibody from which the fragment is derived. The equivalent fragment dose may be calculated according to the fragment molecular weight compared to the molecular weight of the whole antibody, also referred to as parent antibody. For example, if a given antibody has a molecular weight of 150 kD, and a Fab fragment has a molecular weight of 50 kD, then a fragment dose that is one third of the antibody dose should provide an equivalent antagonistic effect on human IL-6. Thus, if the antibody dose was 12 mg/kg, then the equivalent fragment dose for the Fab fragment would be 4 mg/kg. The equivalent antagonistic effect on human IL-6 (or human IL-6R, respectively), may also be determined according to the amount of human IL-6 (or human IL-6R, respectively) that the fragment can specifically bind to, compared to the amount of human IL-6 (or human IL-6R, respectively) that the parent antibody can specifically bind to. These amounts may be determined by various assays, including ELISA.

In a particular embodiment of any of the aspects of the invention, the administration to the subject of the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R is in a dose of 1 mg/kg to 15 mg/kg, such as 1 mg/kg, 1.5 mg/kg, 2 mg/kg, 2.5 mg/kg, 3 mg/kg, 3.5 mg/kg, 4 mg/kg, 4.5 mg/kg, 5 mg/kg, 5.5 mg/kg, 6 mg/kg, 6.5 mg/kg, 7 mg/kg, 7.5 mg/kg, 8 mg/kg, 8.5 mg/kg, 9 mg/kg, 9.5 mg/kg, 10 mg/kg, 10.5 mg/kg, 11 mg/kg, 11.5 mg/kg, 12 mg/kg, 12.5 mg/kg, 13 mg/kg, 13.5 mg/kg, 14 mg/kg, 14.5 mg/kg or 15 mg/kg. For example, the dose of anti-IL-6 antibody may be 11 ± 3 mg/kg, particularly 11 mg/kg. Preferably, the antibody or fragment which is capable of inhibiting human IL-6 is siltuximab. More preferably, the antibody or fragment which is capable of inhibiting human IL-6 is siltuximab, and is administered in a dose of 11 mg/kg. As another example, the dose of anti-IL-6R antibody may be 6 ± 4 mg/kg, optionally 4 mg/kg or 8 mg/kg. Preferably, the antibody or fragment which is capable of inhibiting human IL-6R is tocilizumab. More preferably, the antibody or fragment which is capable of inhibiting human IL-6R is tocilizumab, and is administered in a dose of 4 mg/kg or 8 mg/kg.

Particular dosage regimens of the antibody or fragment include: • administering to a subject on day 1 of treatment a first dose of the antibody or fragment (preferably siltuximab) (i.e., a one dose treatment); or

• administering to a subject on day 1 of treatment a first dose of the antibody or fragment (preferably siltuximab) and administering to a subject on day 3 a second dose of the antibody or fragment (preferably siltuximab) (i.e., a two dose treatment).

Each dose administered in the same dosage regimen does not have to be of the same dosage amount. For example, a subsequent treatment dose may be of a reduced size, e.g. 75%, 50% or 25% of the size of the first treatment dose.

Further, the subject may be administered a different antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R as part of the same dosing regime. For example, the first dose may comprise siltuximab, and the second dose may comprise a different antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R, such as one or more IL-6 inhibitors selected from olokizumab, elsilimomab, mAb 1339, clazakizumab, sirukumab, levilimab MH166, SK2, and ARGX- 109, or one or more IL-6R inhibitors selected from tocilizumab or sarilumab. A third dose may comprise the same antibody or fragment as the first and/or second dose, or a different antibody or fragment as the first and/or second dose.

Alternatively, the same antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R may be used throughout the treatment (e.g., for each dose). Preferably, each dose comprises or consists of siltuximab.

Combination therapy

The treatment of the present invention is a combination therapy of (i) an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R; and (ii) a corticosteroid. The administration of the first treatment dose of the antibody or fragment is within the period 24 hours before or after initiation of the administration of the corticosteroid.

In a particular embodiment of any aspect of the invention, the administration of the first treatment dose of the antibody or fragment is given within the period 2 hours before or after initiation of the administration of the corticosteroid. For example, the first treatment dose of the antibody or fragment may be given within the period 1 hour before or after initiation of the administration of the corticosteroid. In particular embodiments of any aspect of the invention, the combination therapy may further comprise administration of one or more additional immunosuppressant compounds. In particular, the one or more additional immunosuppressant compounds is/are not intended to comprise an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R. Moreover, it will be appreciated that in most embodiments the only inhibitor of IL-6 signaling will be the antibody or fragment which is capable of inhibiting human IL-6 or human IL-6R. Hence, in such embodiments, the immunosuppressive therapy would not comprise any drug which is capable of inhibiting human IL-6 or human IL-6R.

The one or more additional immunosuppressant compounds may be administered by any appropriate route, including as discussed above in respect of administration of the combination therapy.

In a particular embodiment of any aspect of the invention, the administration of one or more additional immunosuppressant compounds is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid. For example, the first treatment dose of the one or more additional immunosuppressant compounds may be given within the period 2 hours before or after initiation of the administration of the corticosteroid, or within the period 1 hour before or after initiation of the administration of the corticosteroid.

In particular embodiments of any aspect of the invention, the one or more additional immunosuppressant compounds may be selected from tacrolimus, pimecrolimus, ciclosporin, sirolimus, everolimus, zotarolimus and methotrexate. In a preferred embodiment of any aspect of the invention, the one or more additional immunosuppressant compounds comprises or consists of tacrolimus.

Tacrolimus, which may be sold under the brand name Prograf among others, is an immunosuppressive drug. Tacrolimus (also FK-506 or Fujimycin) is an immunosuppressive drug. A known use of tacrolimus is after organ transplant to reduce the activity of the patient's immune system and possibly reduce risk of organ rejection. It may also be used in a topical preparation in the treatment of severe atopic dermatitis, severe refractory uveitis after bone marrow transplants, and the skin condition vitiligo. It was discovered in 1984 from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. Tacrolimus is chemically known as a macrolide. It may reduce peptidyl-prolyl isomerase activity by binding to the immunophilin FKBP-12 (FK506 binding protein) creating a new complex. This FKBP12-FK506 complex may inhibit calcineurin which may inhibit T-lymphocyte signal transduction and IL-2 transcription.

In a particular embodiment of any aspect of the invention, the antibody is siltuximab, the corticosteroid is prednisolone and the one or more additional immunosuppressant compounds is tacrolimus. For example, in a particular further embodiment of any aspect of the invention, the antibody is siltuximab that is administered at a dose of 11 mg/kg, the corticosteroid is prednisolone that is administered at a dose of 2 mg/kg/day and the one or more additional immunosuppressant compounds is tacrolimus optionally wherein the tacrolimus is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the prednisolone. In some embodiments of any aspect of the invention, the tacrolimus may be administered at 2x daily dose or twice daily.

DESCRIPTION OF THE FIGURES

Figure 1 is a scheme of the phase II study described in Example 1.

EXAMPLES

Example 1: A phase II study to assess the efficacy and tolerability of siltuximab plus corticosteroids in first line treatment of grade III/IV acute graft versus host disease of the liver of/and the gastro-intestinal tract

See Figure 1 for Scheme of Study.

1. Study Synopsis

1.1. Rationale

The purpose of this study is to evaluate the efficacy of the IL-6 inhibitor siltuximab in combination with prednisolone and tacrolimus as first line therapy in patients with Magic grades III to IV acute graft-versus-host disease (aGVHD) of the liver and/or gastro-intestinal tract.

The rationale for Siltuximab is: 1) standard treatment of aGVHD with high dose steroids is associated with a response rate of 40-60%. Outcome of patients with liver and /or GI aGVHD non-responsive to steroids is dismal. 2) IL-6 is a modulator of the immune response involved in aGVHD and is an important mediator of immune cell trafficking to inflamed tissues and lymphoid organs. 3) Levels of IL-6 and IL-6 receptor are increased in mice with aGVHD, with the highest expression observed in the visceral organs. 4) Blockade of IL-6 receptor signaling resulted in a reduction in aGVHD-related mortality in murine models. 5) Several early reports describe encouraging activity of IL-6 inhibitors for the treatment steroid refractory aGVHD after HOT.

The rationale to apply siltuximab in the front line therapy of aGVHD is to induce early response in a great number of patients avoiding the toxicity of prolonged administration of steroids and reduce the probability of relapse of the hematological disease due to prolonged immunosuppression.

1.2. Study objectives

Primary objective

3. To assess the efficacy of siltuximab added to first-line corticosteroids and tacrolimus in severe acute graft versus host disease of the liver and/or the gastro-intestinal tract.

Secondary objectives

4. Safety and toxicity assessment.

1.3. Study design

This is a prospective, open label, non-randomized phase II study.

1.4. Patient population

Patients with diagnosis of aGVHD grade III-IV involving gut and/or liver according to the MAGIC criteria.

1.5. Intervention

Patients with aGVHD (as specified in patient population) will be treated at diagnosis with high dose prednisolone (2 mg/kg/day) + tacrolimus according to local protocol. In addition, they will receive 11 mg/kg siltuximab on day 1. After 3 days, in patients with progressive disease (PD) ruxolitinib 10 mg b.i.d. will be added. Patients with very good partial remission (VGPR) or complete remission (CR) will continue the already initiated therapy. Only patients with partial remission (PR) or stable disease (SD) will receive another dose of siltuximab 11 mg/kg. On day 7 patients with SD or PD will receive second line treatment with ruxolitinib 10 mg b.i.d.

Prednisolone will be tapered from day 7 onwards according to response to therapy: 1. VGPR or OR: reduce prednisolone to 1 mg/kg and thereafter the prednisolone with 10% every 3 days

2. PR: reduce prednisolone 10% every 5 days.

3. SD or PD: taper prednisolone 10% every 5 days until 1 mg/kg. Concomitant therapy at the discretion of the treating physician.

1.6. Duration of treatment

The study duration will be approximately 2.0 years.

1.7. Target number of patients

For the calculation of the number of patients to be included in the study, we use the Simon's two-stage design. The null hypothesis, that the true response rate (CR) is 50%, will be tested against a one-sided alternative. In the first stage, 14 patients will be accrued. If there are 7 or fewer responses in these 14 patients, the study will be stopped. Otherwise 9 additional patients will be accrued for a total of 23 patients. The null hypothesis will be rejected if 16 or more responses are observed in 23 patients. This design yields a type I error rate of 0.0462 and power of 0.8016 when the true response rate is 75%.

1.8. Main study endpoints

Proportion of patients who experience a complete response (CR) or a very good partial remission (VGPR) of the aGVHD at day +28 after start steroids without treatment failure (initiation of secondary treatment, progression/relapse, or death)

1.9. Benefit and nature and extent of the burden and risks associated with participation

The benefit of this study is to optimize the treatment of aGVHD of the gut and/or liver. This because aGVHD is still the major determinant of non-relapse mortality in patients treated with allogeneic stem cell transplantation. We aim to improve the outcome of these patients by early inhibition of IL-6, which plays a major role in the onset and perpetuation of visceral aGVHD.

The burden and risks associated with participation mainly involves potential toxicity associated with the study drug and taking of additional blood during routine blood draws.

1.10. Planned interim analysis An interim analysis for safety will be performed after 7 patients have been included in the study.

2. Study objectives

2.1. Primary objectives

• To assess the efficacy of siltuximab added to first-line corticosteroids and tacrolimus in severe acute graft versus host disease of the gastro-intestinal tract and/or the liver.

2.2. Secondary objectives

• To assess safety and toxicity of the use of front-line combination siltuximab/steroids/tacrolimus in severe acute GVHD (MAGIC grade III-IV with gut and/or liver involvement).

3. Study design

This is an open label phase II study.

3.1. Design of the current protocol

Patients with aGVHD (as specified in study population) will be treated at diagnosis with high dose prednisolone + tacrolimus according to local protocol. In addition, they will receive siltuximab llmg/kg on day 1. After 3 days, in patients with PD ruxolitinib will be added. Patients with VGPR or CR will continue the already initiated therapy. Only patients with PR or SD will receive another dose of siltuximab llmg/kg. On day 7 patients with SD or PD will receive second line treatment with ruxolitinib 10 mg b.i.d.

Prednisolone will be tapered from day 7 onwards according to response to therapy Details of all treatments (dose and schedule) are given in section 5 below.

4. Study population

4.1. Eligibility

Inclusion criteria

• Age > 18;

• Previously treated with allo-SCT/ DLI;

• MAGIC Grade III-IV acute GVHD involving gut and/or liver (ie gut stage > 2 and/or liver stage > 2) (see Appendix herein);

• WHO performance 0-3;

• Negative pregnancy test (if applicable); • Patients must be willing and capable to use adequate contraception during therapy (if applicable);

• Written Informed Consent by the patient;

• Patient is capable of giving informed consent.

Exclusion criteria

• Patients with active, uncontrolled infection;

• Rapid progressive hematological malignancy;

• Patients pre-treated with prednisolone > 1 mg/kg for GVHD, for more than 24 hours prior to start siltuximab;

• Concurrent severe and/or uncontrolled medical condition (e.g. uncontrolled diabetes, infection, hypertension, cancer, etc.);

• Clinical heart failure with New York Heart Association class >2 or LVEF <30%;

• Liver dysfunction as indicated by total bilirubin, AST and/or ALT >5 x institutional ULN, unless directly attributable to aGVHD;

• CrCI <30 mL/min calculated according to the modified formula of Cockcroft and Gault or by direct urine collection;

• History of severe immediate hypersensitivity reaction against any drug or its ingredients/impurities that is scheduled to be given during trial participation;

• Any psychological, familial, sociological and/or geographical condition potentially hampering compliance with the study protocol and follow-up schedule;

• Known allergy to siltuximab.

5. Treatment

5.1. Siltuximab

Patients with aGVHD (as specified in study population) will be treated at diagnosis with high dose prednisolone (2 mg/kg/day) + tacrolimus according to local protocol. In addition, they will receive 11 mg/kg siltuximab on day 1 (day 1 will be considered the first day of siltuximab administration, a first dose of prednisolone before administration of siltuximab is permitted and will be considered day 0). After 3 days, in patients with PD ruxolitinib 10 mg b.i.d. will be added. Patients with VGPR or OR will continue the already initiated therapy. Only patients with PR or SD will receive another dose of siltuximab 11 mg/kg. On day 7 patients with SD or PD will receive second line treatment with ruxolitinib according to local standards.

Prednisolone will be tapered from day 7 onwards according to response to therapy. 1. CR: reduce prednisolone to 1 mg/kg and thereafter the prednisolone with 10% every 3 days.

2. VGPR or PR: reduce prednisolone 10% every 5 days.

No dose adjustments of siltuximab will be made.

Supportive care for GVHD will be provided according to local protocol and will minimally include:

• monitoring of CMV/EBV;

• prophylaxis of PCP and VZV;

• azole-prophylaxis (e.g. posaconazol 300mg of voriconazole, 2x200 mg/day orally).

5.2. Study drug supply, preparation and labelling

Siltuximab will be supplied by Recordati.

Siltuximab should be diluted to a final volume of 100 mL with sterile, non-pyrogenic sodium chloride 9 mg/mL (0.9%) solution for injection using aseptic technique.

Siltuximab to be administered by intravenous infusion.

In this study we plan to give a maximum of two doses of the study drug.

6. Study procedures

6.1. Time of clinical evaluations

For all study procedures, the day of admission with aGVHD and start of high-dose prednisone is counted as day 1.

Clinical evaluations at timepoints:

- At day 1;

- At day 3;

- At day 7;

- At day 14, 21, 28, evaluation +/- 2 days allowed;

- At day 60 and 100, evaluation +/- 4 days allowed.

All patients will be followed until 12 months after registration. 6.2. Required investigations

Table 1: Overview of required investigations at entry and during treatment

(x) = on indication

Specification of reguired investigations

Medical history

Standard medical history, including medication

Physical examination

Standard physical examination including body weight and height, with special attention for:

- Vital signs (temperature, saturation, pulse, blood pressure)

- Assessment of fecal volume and frequency

Hematology

Hemoglobin

Platelets

- WBC

WBC differential (either automatically or manually) Blood chemistry

Creatinine

- Albumin

Bilirubin (direct +indirect)

- ALT/AST

- LDH

- CRP

- IL-6 at onset of disease

A dditional/Specific in vestiga tions

Fecal microbiology including C diff, viral, Cryptosporidium, microsporidium

- Sigmoidoscopy

- Sigmoid biopsy evaluated for viral load (CMV, HHV-6) and pathology

6.3. Toxicity assessment

After treatment with siltuximab toxicity has to be carefully examined and evaluated. During the clinical phase a daily assessment of toxicities will be performed. After discharge patients will be followed until 12 months after inclusion in the protocol. In the outpatient setting an assessment of toxicities will be performed. The toxicity assessment includes the following:

• Complete history of symptoms and complaints

• Complete physical examination

• Laboratory examination of hemogram, ALT/AST, bilirubin, Creatinin, LDH; other parameters as clinically indicated

• Instrumental investigations when clinically indicated according to clinician opinion

Toxicities will be reported as described in section 8.2 below.

Toxicities will be scored according to the most recent version of the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.

7. Withdrawal of individual patients from protocol treatment

Patients should be withdrawn from protocol treatment if any of the following criteria for withdrawal are met:

• Patient not eligible in hindsight, patients will be followed according to the intention to treat protocol; • Other adverse event preventing further treatment;

• Major protocol violation.

Patients can leave the study at any time for any reason if they wish to do so without any consequences. The investigator can also decide to withdraw a patient from protocol treatment for other reasons than the criteria described above. Examples of such reasons for withdrawal from protocol treatment are:

• Refusal of patient to continue protocol treatment;

• No compliance of the patient: patient is unable or unwilling to adhere to the treatment schedule and/or procedures required by the protocol.

Patients who are withdrawn from protocol treatment will receive medical care according to local practice.

8. Safety

8.1. Definitions

Adverse event (AE)

An adverse event (AE) is any untoward medical occurrence in a patient or clinical study subject administered a medicinal product and which does not necessarily have a causal relationship with the treatment.

An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product.

Serious adverse event (SAE)

A serious adverse event is defined as any untoward medical occurrence or effect that at any dose:

• Results in death;

• Is a life-threatening event (i.e. the patient was at immediate risk of death at the time the reaction was observed);

• Requires hospitalization or prolongation of an existing hospitalization;

• Results in significant or persistent disability or incapacity;

• Is a congenital anomaly or birth defect;

• Is an important medical event (i.e. important adverse events that are not immediately life threatening or do not result in death or hospitalization but may jeopardize the patient or may require intervention to prevent one of the above characteristics/consequences, including suspected transmission of infectious agents by a medicinal product). serious adverse reaction

All suspected Adverse Reactions which occur in the trial and that are both unexpected and serious.

Suspected adverse reactions (AR) are those AEs of which a reasonable causal relationship to any dose administered of the investigational medicinal product and the event is suspected. Unexpected adverse reactions are adverse reactions, of which the nature, or severity, is not consistent with the applicable product information (e.g. Investigator's Brochure for an unapproved IMP or Summary of Product Characteristics (SPC) for an authorized medicinal product).

Adverse Events of Special Interest (AESI)

In general, AESIs are adverse events (AEs) that occur in categories of special interest with regard to determining the benefit-risk profile and overall safety of a drug. Ten categories of AESIs have been identified:

• Serious and/or Medically Significant Infections

• Myocardial Infarction/ Acute Coronary Syndrome (MI/ACS)

• Gastrointestinal Perforations

• Malignancies

• Anaphylaxis/Hypersensitivity Reactions

• Demyelinating Disorders

• Stroke

• Serious and/or Medically Significant Bleeding Events

• Serious and/or Medically Significant Hepatic Events

• Pancreatitis

8.2. Adverse event of adverse events

Adverse events grade 4 will be reported from the first study-related procedure until 30 days following the last dose of siltuximab. Adverse events grade 4 occurring after 30 days should also be reported if considered at least possibly related to the investigational medicinal product by the local investigator.

Adverse events have to be reported on the Adverse Events CRF. Adverse events will be scored according to the NCI Common Terminology Criteria for Adverse Events, version 5. SUSARS will be reported within 7 calendar days and SAE's and AESIs within 15 calendar days, according to national regulations.

Pre-existing conditions will be collected on the baseline concomitant diseases CRF, i.e. active (symptomatic) diseases of CTCAE grade > 2 diseases under treatment, chronic diseases and long term effects of past events as present at the time of baseline assessment.

AEs of CTCAE grade > 4 will be recorded up to 30 days after the last dose of study treatment. Thereafter only AE's of CTCAE grade >3 and all SAEs, SUSARs and AESIs will be reported.

All adverse events have to be reported, with the exception of:

• A pre-existing condition that does not increase in severity; the pre-existing condition should be reported on the baseline concomitant diseases CRF;

• AE's of CTCAE grade <4;

• Abnormal laboratory values that have been recorded as being not clinically significant by the investigator in the source documents;

• Relapse/Progression of the disease under study; complications as a result of disease progression remain reportable adverse events if they occur within 30 days of last study treatment.

Follow up of adverse events

All adverse events will be followed clinically until they have been resolved, or until a stable situation has been reached. Depending on the event, follow up may require additional tests or medical procedures as indicated, and/or referral to the general physician or a medical specialist.

On the AE CRF only the incidence of adverse events is recorded. Any ongoing adverse event that increases in severity has to be reported as a new adverse event on the CRF. Other follow up information is not collected on the CRF. 8.3. Serious Adverse Events

Reporting of serious adverse events

Serious Adverse Events (SAEs) will be reported from the first study-related procedure until 30 days following the last dose of siltuximab.

Serious adverse events occurring after 30 days should also be reported if considered at least possibly related to the investigational medicinal product by the investigator. Causality assessment of Serious Adverse Events

The investigator will decide whether the serious adverse event is related to siltuximab. The decision will be recorded on the serious adverse event report. The assessment of causality is made by the investigator using the following: Table 2: Causality assessment criteria

Follow up of Serious Adverse Events

All serious adverse events will be followed clinically until they are resolved or until a stable situation has been reached. Depending on the event, follow up may require additional tests or medical procedures as indicated, and/or referral to the general physician or a medical specialist.

Follow up information on SAE's should be reported every two weeks until recovery or until a stable situation has been reached. The final outcome of the SAE should be reported on a final SAE report.

9. Endpoints

9.1. Primary endpoint

Proportion of patients who experience a CR or a VGPR of the aGVHD at day +28 after start steroids without treatment failure (initiation of secondary treatment, progress ion/ re I apse, or death).

9.2. Secondary endpoints

• Time to CR - Combined PR/VGPR and/ or CR on day +28 and +56

• Percentage of patients in need of ruxolitinib

• Severe adverse events

• Incidence and severity of cGVHD

• Overall survival at 6 months

• Incidence of relapse/RFS at 6 months

9.3. Definitions

• CR: resolution of all signs and symptoms of acute GVHD;

• VGPR: improvement in GVHD in all initial GVHD target organs, with maximum remaining stage I involvement in one or more organs (except upper gastrointestinal tract), without secondary GVHD therapy; o Liver:

■ Total serum bilirubin concentration <2 mg/dL (34.2 micromol/L) or <25% of baseline at enrolment; o Gut:

Tolerating food or enteral feeding; ■ Predominantly formed stools;

■ No overt gastrointestinal bleeding or abdominal cramping

■ No more than occasional nausea or vomiting;

• PR: improvement in GVHD stage in all initial GVHD target organs without OR or VGPR and without worsening in any other GVHD target organs;

• SD: not fulfilling the criteria of OR, VGPR, or PD;

• PD: worsening GVHD in >1 organ with or without amelioration in any other target organ;

• Overall survival (OS) is defined as the time from start first siltuximab to the date of death, whatever the cause. The follow-up of patients still alive will be censored at the moment of last visit/contact.

10. Statistical considerations

This is an open label, non-randomized trial. All patients fulfilling the inclusion criteria and willing to give informed consent will be included. Patients will not be stratified according to organ involvement, disease status at transplantation or comorbidities.

10.1. Statistical analysis

For this phase II trial we will use a two-stage design which allows for flexibility to stop the trial early for futility. We will use the Simon' s two-stage design. Using this design, the trial will be conducted in two stages with the option to stop the trial after the first or after the second stage. The basic approach is to "minimize" expected sample size when the true response is low.

Efficacy analysis

Primary endpoint and secondary endpoints will be considered. Progression free survival (PFS) and overall survival (OS) will be estimated by the Kaplan-Meier method, and 95% confidence intervals (Cis) will be constructed. The respective hazard ratios (HRs) with 95% Cis will also be calculated. Kaplan-Meier curves will be generated to illustrate survival.

Toxicity analysis

The analysis of toxicity will be done primarily by tabulation of the incidence, nature and severity of adverse events with CTCAE grade 3 or more.

10.2. Statistical analysis plan

The Simon's two stage design will be used. The null hypothesis, that the true response rate (CR) is 50%, will be tested against a one-sided alternative. In the first stage, 14 patients will be accrued. If there are 7 or fewer responses in these 14 patients, the study will be stopped. Otherwise 9 additional patients will be accrued for a total of 23 patients. The null hypothesis will be rejected if 16 or more responses are observed in 23 patients. This design yields a type I error rate of 0.0462 and power of 0.8016 when the true response rate is 75%.

REFERENCES

1. D'Souza A, Fretham C, Lee SJ, et al. Current Uses and Outcomes of Hematopoietic Cell Transplantation in the united states. Biol Blood Marrow transplant 2020;26:el77-el82.

2. Pavletic SZ, Fowler DH. Are we making progress in GVHD prophylaxis and treatment? Hematol Am Soc Hematol Educ Program. 2012;2012:251-64.

3. Xhaard A, Rocha V, Bueno B, et al. Steroid -refractory acute GVHD: Lack of long term improved survival using new generation anti-cytokine treatment. Biol Blood Marrow Transplant. 2012;18:406-13.

4. Castilla-Llorente C, Martin PJ, McDonald GB, et al. Prognostic factors and outcomes of severe gastrointestinal graft-vs.-host disease after allogeneic hematopoietic cell transplantation. Bone Marrow Transplant. 2014;49:966-71.

5. Martin PJ, McDonald GB, Sanders JE, et al. Increasingly frequent diagnosis of acute gastrointestinal graft-versus-host disease after allogeneic hematopoietic cell transplantation. Biol Blood Marrow Transplant. 2004;10:320-27.

6. Scheller J, Chalaris A, Schmidt-Arras D, Rose-John S. The pro and anti- inflammatory properties of the cytokine interleukin-6. Biochim Biophys Acta. 2011;1813:878-88.

7. Tvedt THA, Ersvaer E, Tveita AA, Bruserud O. Interleukin-6 in allogeneic stem cell transplantation: its possible importance for immunoregulation and as a therapeutic target. Front Immunol. 2017;8: 1-15.

8. Chen X, Das R, Komorowski R, Beres A, Hessner MJ, Mihara M, et al. Blockade of interleukin-6 signaling augments regulatory T- cell reconstitution and attenuates the severity of graft-versus-host disease. Blood. 2009;114:891-900.

9. Tawara I, Koyama M, Liu C, Toubai T, Thomas D, Evers R, et al. Interleukin-6 modulates graft-versus-host responses after experimental allogeneic bone marrow transplantation. Clin Cancer Res. 2011;17:77-88.

10. Drobyski WR, Pasquini M, Kovatovic K, Palmer J, Douglas Rizzo J, Saad A, et al. Tocilizumab for the treatment of steroid refractory graft-versus-host disease. Biol Blood Marrow Transplant. 2011;17: 1862-68.

11. Roddy JV, Haverkos BM, McBride A, Leininger KM, Jaglowski S, Penza S, et al. Tocilizumab for steroid refractory acute graft versus-host disease. Leuk Lymphoma. 2016;57:81-5.

12. Ganetsky A, Frey NV, Hexner EO et al. Tocilizumab for the treatment of severe steroid- refractory acute graft-versus-host disease of the lower gastrointestinal tract. Bone Marrow transplant 2019;54:212-217.

13. Yucebay F, Matthews C, Puto M, et al Tocilizumab as first-line therapy for steroid- refractory acute graft-versus-host-disease: analysis of a single-center experience. Leuk Lymphoma 2019:60:2223-2229. 14. "Monoclonal Antibodies; A manual of techniques", H Zola (CRC Press, 1988)

15. "Monoclonal Hybridoma Antibodies: Techniques and Application", SGR Hurrell (CRC Press, 1982)

16. Lee, E., Liang, Q., Ali, H. et al. Complete humanization of the mouse immunoglobulin loci enables efficient therapeutic antibody discovery. Nat Biotechnol 32, 356-363 (2014). https://doi.org/10.1038/nbt.2825

17. Neuberger et al (1998, 8th International Biotechnology Symposium Part 2, 792- 799)

18. Eur. J. Biochem (1987) 168, 543-550

19. J. Immunol. (1988)140, 1534-1541

20. Agr. Biol. Chem. (1990)54, 2685-2688

21. Chen F et al "Measuring IL-6 and sIL-6R in serum from patients treated with tocilizumab and/or siltuximab following CART cell therapy" J. Immunol. Methods 2016, 434, 1-8

22. Brakenhoff, J. et al. (1990) J. Immunology 145: 561-568

23. Shaw, S., Bourne, T., Meier, C., Carrington, B., Gelinas, R., & Henry, A., et al., (2014), Discovery and characterization of olokizumab, mAbs, 6(3), 773-781

24. Wijdenes J, Clement C, Klein B, et al., Human recombinant dimeric IL-6 binds to its receptor as detected by anti-IL-6 monoclonal antibodies, Mol Immunol. 1991;28(11): 1183-1192

25. Fulciniti, M., Hideshima, T., Vermot-Desroches, C., Pozzi, S., Nanjappa, P., Shen, Z.,. & Tai, Y. T., (2009), A high-affinity fully human anti-IL-6 mAb, 1339, for the treatment of multiple myeloma, Clinical Cancer Research, 15(23), 7144-7152

26. Mease PJ, Gottlieb AB, et al. (September 2016). "The efficacy and safety of clazakizumab, an anti-interleukin-6 monoclonal antibody, in a phase lib study of adults with active psoriatic arthritis". Arthritis Rheumatol. 68 (9): 2163-73

27. Smolen JS, Weinblatt ME, Sheng S, Zhuang Y, Hsu B. Sirukumab, a human antiinterleukin-6 monoclonal antibody: a randomised, 2-part (pro of- of- co nee pt and dosefinding), phase II study in patients with active rheumatoid arthritis despite methotrexate therapy. Ann Rheum Dis. 2014 Sep;73(9): 1616-25. doi: 10.1136/annrheumdis-2013-205137. Epub 2014 Apr 3. PMID: 24699939; PMCID: PMC4145446

28. Matsuda, T. et al., Eur. J. Immunol. (1988) 18, 951-956

29. Sato, K. et al., The abstracts of the 21st Annual Meeting of the Japanese Society for Immunology (1991) 21, 166

30. Levilimab, Wikipedia entry, "https://en.wikipedia.org/wiki/Levilimab" accessed 19 April 2024 31. M. Mihara et al., "Tocilizumab inhibits signal transduction mediated by both mlL- 6R and SIL-6R, but not by the receptors of other members of IL-6 cytokine family" Int. Immunopharmacol.(2005)

32. Alexandra H. Filipovich et al., National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host

Disease: I. Diagnosis and Staging Working Group Report, 2005

33. Lee SJ. Classification systems for chronic graft-versus-host disease. Blood. 2017 Jan 5;129(l):30-37. doi: 10.1182/blood-2016-07-686642. Epub 2016 Nov 7. PMID: 27821503; PMCID: PMC5216262.

APPENDIX

Table 3 - GVHD Target Organ Staging

Overall clinical grade (based upon most severe target organ involvement):

Grade 0: No stage 1-4 of any organ.

Grade I: Stage 1-2 skin without liver; Upper GI or lower GI involvement.

Grade II: Stage 3 rash and/or stage 1 liver and/or stage 1 upper GI and/or stage 1 lower GI.

Grade IV: Stage 4 skin, liver or lower GI involvement, with stage 0-1 upper GI.

Claims

1. A method of treatment of graft-versus-host disease in a subject in need thereof, wherein the treatment is a first-line treatment of graft-versus-host disease, the method comprising a combination therapy of:

(i) administration to the subject of an antibody or fragment which is capable of inhibiting human IL-6 or human IL-6 receptor; and

2. The method according to Claim 1, wherein the subject is a human.

3. The method according to Claim 1 or 2, wherein the method is initiated after transplant of haematopoietic cells, haematopoetic stem cells, haematopoetic tissue, a haematopoietic organ, bone marrow or stem cells from a donor.

4. The method according to any one of Claims 1-3, wherein the graft-versus-host disease is acute graft-versus-host disease and the treatment is a first-line treatment of acute graft-versus-host disease.

5. The method according to Claim 4, wherein the subject has not previously received corticosteroid treatment for acute graft-versus-host disease.

6. The method according to Claim 4 or 5, wherein the acute graft-versus-host-disease is grade III or grade IV according to the Mount Sinai Acute GVHD International Consortium (MAGIC) criteria.

7. The method according to any one of Claims 1-3, wherein the graft-versus-host disease is chronic graft-versus-host disease and the treatment is a first-line treatment of chronic graft-versus-host disease.

8. The method according to Claim 7, wherein the subject has not previously received corticosteroid treatment for chronic graft-versus-host disease.

9. The method according to any one of Claims 1-8, wherein the antibody or fragment is a chimeric, humanized or CDR grafted antibody or fragment thereof.

10. The method according to any one of Claims 1-9, wherein the antibody or fragment is an anti-IL-6 antibody or fragment.

11. The method according to Claim 10, wherein the anti-IL-6 antibody or fragment is a chimeric, humanized or CDR grafted antibody or fragment thereof comprising a heavy chain variable region in which CDR1, CDR2 and CDR3 comprise the amino acid sequences of SEQ ID NO: 1, SEQ ID NO: 2 and SEQ ID NO: 3, respectively; and a light chain variable region in which CDR1, CDR2 and CDR3 comprise the amino acid sequences of SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6, respectively; and a constant region derived from a human IgG antibody.

12. The method according to Claim 10 or 11, wherein the anti-IL-6 antibody is selected from siltuximab, olokizumab, elsilimomab, mAb 1339, clazakizumab, sirukumab, levilimab, MH166, SK2, and ARGX-109.

13. The method according to any one of Claims 10-12, wherein the anti-IL-6 antibody is siltuximab.

14. The method according to any one of Claims 1-9, wherein the antibody or fragment is an anti-IL-6-receptor antibody or fragment.

15. The method according to Claim 14, wherein the anti-interleukin-6-receptor antibody is selected from tocilizumab and sarilumab.

16. The method according to any one of Claims 1-15, wherein the first treatment dose of the antibody or fragment is given within the period 2 hours before or after initiation of the administration of the corticosteroid.

17. The method according to any one of Claims 1-16, wherein the antibody or fragment is administered by intravenous administration, optionally by infusion, optionally over the course of one hour.

18. The method according to any one of Claims 1-17, wherein the dose of the anti-IL- 6 antibody is 11 ± 3 mg/kg subject body weight, optionally 11 mg/kg; or wherein the dose of the anti-IL-6 antibody fragment is a dose having an equivalent antagonistic effect on human IL-6.

19. The method according to any one of Claims 1-17, wherein the dose of the anti-IL- 6-receptor antibody is 6 ± 4 mg/kg subject body weight, optionally 4 mg/kg or 8 mg/kg; or wherein the dose of the anti-IL-6-receptor antibody fragment is a dose having an equivalent antagonistic effect on human IL-6 receptor.

20. The method according to any one of Claims 1-6, 9-19, wherein administering the first treatment dose of the antibody or fragment in the combination therapy reduces the severity of one or more measures of acute graft-versus-host disease according to the MAGIC criteria.

21. The method according to any one of Claims 1-3, 7-19, wherein administering the first treatment dose of the antibody or fragment in the combination therapy reduces the severity of, or eliminates, one or more symptoms of chronic graft-versus-host disease.

22. The method according to any one of Claims 1-21, wherein the method comprises administering a second treatment dose of the antibody or fragment after the first treatment dose, if clinically indicated.

23. The method according to Claim 22, wherein the second treatment dose of the antibody or fragment is clinically indicated if the graft-versus-host disease is at the same stage or has partial remission, when assessed on day 3 wherein day 1 is the day of the first treatment dose of the antibody or fragment, or when assessed between 36 and 60 hours after the first treatment dose of the antibody or fragment.

24. The method according to Claim 22 or 23s, wherein the second treatment dose of the antibody or fragment is administered on day 3 wherein day 1 is the day of the first treatment dose of the antibody or fragment, or is administered between 36 and 60 hours after the first treatment dose of the antibody or fragment.

25. The method according to any one of Claims 22-24, wherein the treatment is first- line treatment of aGVHD and administering the second treatment dose of the antibody or fragment in the combination therapy reduces the severity of one or more measures of acute graft-versus-host disease according to the MAGIC criteria.

26. The method according to any one of Claims 22-24, wherein the treatment is first- line treatment of cGVHD and administering the second treatment dose of the antibody or fragment in the combination therapy reduces the severity of, or eliminates, one or more symptoms of cGVHD.

27. The method according to any one of Claims 1-26, wherein the corticosteroid is selected from prednisolone, prednisone, methylprednisolone, cortisone, dexamethasone, betamethasone and hydrocortisone.

28. The method according to Claim 27, wherein the corticosteroid comprises or consists of prednisolone.

29. The method according to Claim 28, wherein the corticosteroid comprises or consists of prednisolone administered at a dose of 2 mg/kg/day.

30. The method according to any one of Claims 1-29, wherein the corticosteroid dose is tapered from day 7 onwards according to response to the therapy, wherein day 1 is the day of the first treatment dose of the antibody or fragment.

31. The method according to any one of Claims 1-30, wherein the combination therapy further comprises administration of one or more additional immunosuppressant compounds.

32. The method according to Claim 31, wherein the administration of one or more additional immunosuppressant compounds is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

33. The method according to Claim 31 or 32, wherein the one or more additional immunosuppressant compounds are selected from tacrolimus, pimecrolimus, ciclosporin, sirolimus, everolimus, zotarolimus and methotrexate.

34. The method according to Claim 33, wherein the one or more additional immunosuppressant compounds comprises or consists of tacrolimus.

35. The method according to any one of Claims 31-34, wherein the antibody is siltuximab, the corticosteroid is prednisolone and the one or more additional immunosuppressant compounds is tacrolimus.

36. The method according to Claim 35, wherein the siltuximab is administered at a dose of 11 mg/kg, the prednisolone is administered at a dose of 2 mg/kg/day and tacrolimus is administered, optionally wherein the tacrolimus is given in a first treatment dose within the period 24 hours before or after initiation of the administration of the prednisolone.

37. An anti-IL-6 or anti-IL-6-receptor antibody or fragment for use in first-line treatment of graft-versus-host disease, wherein the first-line treatment comprises a combination therapy of administration of the antibody or fragment and administration of a corticosteroid, and wherein the administration of the antibody or fragment is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

38. Use of an anti-IL-6 or anti-IL-6-receptor antibody or fragment in first-line treatment of graft-versus-host disease, wherein the first-line treatment comprises a combination therapy of administration of the antibody or fragment and administration of a corticosteroid, and wherein the administration of the antibody or fragment is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

39. Use of an anti-IL-6 or anti-IL-6-receptor antibody or fragment for the manufacture of a medicament for first-line treatment of graft-versus-host disease, wherein the medicament is to be administered in a combination therapy with administration of a corticosteroid, and wherein the administration of the medicament is to be given in a first treatment dose within the period 24 hours before or after initiation of the administration of the corticosteroid.

40. The anti-IL-6 or anti-IL-6-receptor antibody or fragment for use according to Claim

37, or the use of an anti-IL-6 or anti-IL-6-receptor antibody or fragment according to Claim 38 or 39, having any of the additional features of any of Claims 1 to 36.