Bispecific antibodies against CD3 and CD20 for the treatment of Richter's syndrome

Abstract

A method for the clinical treatment of Richter's syndrome in human subjects is provided using a bispecific antibody that binds to CD3 and CD20.

Description

[Technical Field]

[0001] Field The present invention relates to the use of bispecific antibodies targeting both CD3 and CD20 in the treatment of Richter's syndrome (RS), and also provides advantageous treatment regimens. [Background technology]

[0002] background Chronic lymphocytic leukemia (CLL) is a B-cell malignancy resulting from the uncontrolled proliferation of immature lymphocytes in the bone marrow, accompanied by circulating tumor cells in the blood. CLL is characterized by the accumulation of clonal CD5+CD19+CD20+CD23+ B cells in the bone marrow, blood, and lymphoid organs, such as lymph nodes and spleen (Zenz et al., Nat Rev Cancer 2010;10:37-50). CLL is often a slowly progressive cancer. CLL is primarily a disease of older adults, with a median age at diagnosis of 70 years. CLL is the most common leukemia among adults in Western countries, accounting for approximately 25%-30% of all leukemias in the United States, with an estimated 20,720 new cases and 3,930 deaths (Siegel et al., CA Cancer J Clin 2019;69:7-34). Approximately 105,000 cases are reported annually worldwide, resulting in 35,000 deaths (Global Burden of Disease Cancer, Fitzmaurice et al., JAMA Oncol 2018;4:1553-68).

[0003] In contrast, lymphomas result from the uncontrolled proliferation of lymphocytes in organs other than the bone marrow. In some lymphomas, the bone marrow may also show tumor cell infiltration, but lymphoma cells are not usually found in the peripheral blood.

[0004] Richter's syndrome (RS), also known as Richter's transformation (RT), is an aggressive lymphoma that develops in the setting of CLL or SLL (small lymphocytic lymphoma) (Swerdlow et al., 2017; WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues, International Agency for Research on Cancer, Lyon, France). The annual incidence of RS in patients with CLL is estimated to be approximately 0.5%–1%, with an overall incidence of approximately 5%–16% of all CLL patients (Rossi et al., Br J Haematol, 2008;142, 202–215). Recent studies have shown that Richter's syndrome occurs in approximately 2–10% of all CLL / SLL patients during the course of their disease (Wang Y et al., Haematologica. 2020;105:765–73). In 90% of cases, RS presents as diffuse large B-cell lymphoma (RS-DLBCL) (Parikh et al., Br J Haematol, 2013; 162, 774-782; Rossi et al., Br J Haematol, 2008; 142, 202-215). Approximately 80% of RS-DLBCL are clonally related to the original CLL, which is historically resistant to chemotherapy, and the median survival is 12 months (Eyre et al., Br J Haematol, 2016;175,43-54; Langerbeins et al., Am J Hematol 89, 2014;E239-243; Rogers et al., Br J Haematol, 2018;180,259-266; Tsimberidou et al., Clin Lymphoma Myeloma Leuk, 2013;13,568-574). Monotherapy with novel agents, such as BTK inhibitors and BCL2 inhibitors, has done little to alter the outcome of RS. In 29 patients with RS-DLBCL treated with acalabrutinib, the ORR, median duration of response, and median PFS were 38%, 5 months, and 3 months, respectively (Hillmen et al., Blood, 2016;128,60-60).In seven patients with RS-DLBCL, venetoclax achieved a 43% ORR, although the duration was unknown. Checkpoint inhibitors such as pembrolizumab and nivolumab, either as monotherapy or in combination with BTK inhibitors, have shown ORRs ranging from 40% to 60% and a relatively short PFS of 4 months (Ding et al., Blood 2017;129,3419-3427; Jain et al., Blood 2016;128,59-59; Younes et al., Blood 2017;130,833-833). Due to the short duration of response to chemoimmunotherapy, autologous and allogeneic stem cell transplants are being used as postinduction therapy to extend survival in fit / young patients with RS. However, approximately 80%–90% of patients with RS are ineligible to undergo transplantation due to 1) the inability to achieve remission with induction therapy and 2) comorbidities or age. In summary, even in the era of new drugs, the incidence of RS has not decreased, and the prognosis for patients with RS remains poor.

[0005] Thus, there remains an unmet need for treatment options for patients with Richter's syndrome. Summary of the Invention

[0006] overview Provided herein are methods, particularly advantageous clinical treatment regimens, for treating human subjects exhibiting Richter's syndrome by administering bispecific antibodies that bind to CD3 and CD20.

[0007] In one embodiment, (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that comprises a variable heavy (VH) region and a variable light (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region and comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 14. Provided herein are methods for treating Richter's syndrome in a human subject, comprising administering (e.g., subcutaneously) to the subject an effective amount of a bispecific antibody (e.g., epcolitamab) comprising:

[0008] In some embodiments, the bispecific antibody is administered weekly, for example, for 2.5 28-day cycles (i.e., days 15 and 22 of cycle 1 and days 1, 8, 15, and 22 of cycles 2-3). In some embodiments, the bispecific antibody is administered every two weeks following the weekly administration (e.g., for six 28-day cycles). In some embodiments, the bispecific antibody is administered every four weeks following the biweekly administration. In another embodiment, a priming dose (e.g., 0.05-0.35 mg, e.g., 0.16 mg or about 0.16 mg) of the bispecific antibody is administered two weeks prior to the administration of the 24 mg or 48 mg weekly dose. In another embodiment, the priming dose is administered one week prior to the intermediate dose, which is administered one week prior to the first weekly dose of 24 mg or 48 mg.

[0009] In some embodiments, the bispecific antibody is administered in a 28 day cycle, wherein: a) In cycle 1, a priming dose (e.g., 0.05-0.35 mg, e.g., 0.16 mg or about 0.16 mg) is administered on day 1, an intermediate dose (e.g., 0.6-1.2 mg, e.g., 0.8 mg or about 0.8 mg) is administered on day 8, and full doses of 12-60 mg (e.g., 12 mg, 24 mg, 48 mg, or 60 mg) are administered on days 15 and 22; b) in cycles 2-3, a full dose of 12-60 mg (e.g., 12 mg, 24 mg, 48 mg, or 60 mg) is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg (e.g., 12 mg, 24 mg, 48 mg, or 60 mg) is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, administer a full dose of 12 to 60 mg (e.g., 12 mg, 24 mg, 48 mg, or 60 mg) on ​​Day 1.

[0010] In another embodiment, the subject has refractory and / or recurrent Richter's syndrome after receiving two prior anti-tumor therapies.

[0011] In some embodiments, a subject is treated for the prevention of cytokine release syndrome (CRS). In some embodiments, the prevention comprises administering a corticosteroid (e.g., prednisolone at a dose of, e.g., 100 mg or its equivalent, including an oral dose), e.g., on the same day as administration of the bispecific antibody. In some embodiments, the corticosteroid is further administered on days 2, 3, and 4 following administration of the bispecific antibody.

[0012] In some embodiments, the subject is administered a premedication to reduce any reaction to the injection, such as an antihistamine (e.g., diphenhydramine, e.g., diphenhydramine administered intravenously or orally at a dose of 50 mg or its equivalent) and / or an antipyretic (e.g., acetaminophen, e.g., acetaminophen at a dose of 560-1000 mg). In some embodiments, the premedication is administered on the same day as administration of the bispecific antibody.

[0013] In some embodiments, prophylaxis and premedication are administered in cycle 1. In some embodiments, if the subject experiences CRS greater than Grade 1 after the final administration of bispecific antibody in cycle 1, prophylaxis is administered in cycle 2. In some embodiments, if the subject experiences CRS greater than Grade 1 upon the final administration of bispecific antibody in the previous cycle, prophylaxis is continued in the subsequent cycle. In another embodiment, premedication is administered in cycle 2. In another embodiment, premedication is administered in the subsequent cycle.

[0014] In some embodiments, if a subject develops Grade 1 CRS, the subject is treated with antipyretics and hydration. In some embodiments, if a subject develops Grade 2 CRS, the subject is treated with tocilizumab and / or dexamethasone or methylprednisolone equivalent. In some embodiments, if a subject develops Grade 3 CRS, the subject is treated with tocilizumab and dexamethasone (e.g., methylprednisolone at a dose of 10-20 mg or its equivalent, e.g., administered once every 6 hours). In another embodiment, if a subject develops Grade 4 CRS, the subject is treated with tocilizumab and methylprednisolone (e.g., at a dose of 1000 mg / day). In another embodiment, if a subject does not respond to tocilizumab, tocilizumab is switched to siltuximab.

[0015] In some embodiments, tumor lysis syndrome (TLS) is prevented in a subject. In some embodiments, preventing TLS involves administering one or more uric acid-lowering agents prior to administration of the bispecific antibody. In some embodiments, allopurinol and rasburicase are administered as uric acid-lowering agents. In another embodiment, allopurinol is administered at least 72 hours prior to administration of the bispecific antibody. In another embodiment, rasburicase is administered after administration of allopurinol and prior to administration of the bispecific antibody. In some embodiments, supportive care, such as rasburicase and / or allopurinol, may be used if the subject shows signs of TLS.

[0016] In some embodiments, a subject treated with the methods described herein achieves a complete response, a partial response, or stable disease, as defined, for example, by the Lugano criteria (Cheson et al., 2014).

[0017] In some embodiments, the first antigen-binding region of the bispecific antibody comprises VHCDR1, VHCDR2 and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 1, 2 and 3, respectively, and VLCDR1, VLCDR2 and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 4, sequence GTN and SEQ ID NO: 5, respectively, and the second antigen-binding region comprises VHCDR1, VHCDR2 and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 8, 9 and 10, respectively, and VLCDR1, VLCDR2 and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 11, sequence DAS and SEQ ID NO: 12, respectively.

[0018] In some embodiments, the first antigen-binding region of the bispecific antibody comprises a VH region comprising the amino acid sequence of SEQ ID NO:6 and a VL region comprising the amino acid sequence of SEQ ID NO:7, and the second antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO:13 and a VL region comprising the amino acid sequence of SEQ ID NO:14.

[0019] In some embodiments, the first binding arm of the bispecific antibody is derived from a humanized antibody, preferably a full-length IgG1, λ (lambda) antibody. In some embodiments, the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1, κ (kappa) antibody. In some embodiments, the bispecific antibody is a full-length antibody having a human IgG1 constant region.

[0020] In some embodiments, the bispecific antibody comprises an inactive Fc region (e.g., an Fc region in which the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively). In some embodiments, the bispecific antibody comprises substitutions that promote the formation of bispecific antibodies, for example, in the first heavy chain, the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain, the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa. In some embodiments, the bispecific antibody has both an inactive Fc region (e.g., substitutions at L234, L235, and D265 (e.g., L234F, L235E, and D265A)) and substitutions that promote the formation of bispecific antibodies (e.g., F405L and K409R). In another embodiment, the bispecific antibody comprises a heavy chain constant region comprising the amino acid sequence of SEQ ID NOs: 19 and 20.

[0021] In some embodiments, the bispecific antibody comprises a first heavy chain and a first light chain comprising (or consisting of) the amino acid sequences set forth in SEQ ID NOs: 24 and 25, respectively, and a second heavy chain and a second light chain comprising (or consisting of) the amino acid sequences set forth in SEQ ID NOs: 26 and 27, respectively. In some embodiments, the bispecific antibody is epcolitamab or a biosimilar thereof. [Brief explanation of the drawings]

[0022] [Figure 1]Phase 1b / 2 clinical trial results: treatment-emergent adverse events; data cutoff: September 8, 2022. [Figure 2] Phase 1b / 2 trial results: CRS events by treatment period; data cutoff: September 8, 2022. [Figure 3] Phase 1b / 2 trial results: depth and duration of response; data cutoff: September 8, 2022. [Figure 4] Phase 1b / 2 trial results. Tumor shrinkage from baseline; data cutoff: September 8, 2022. [Figure 5] Clinical case study (RS-DLBCL). A: Baseline PET / CT scan, mesenteric mass: 11.6 x 7.2 cm, abdominal / pelvic mass standardized uptake value (SUV) maximum 6.3. B: 12-week PET / CT scan, mesenteric mass: 0.5 x 0.5 cm, abdominal / pelvic mass SUV maximum 2.0. C: 76-week PET / CT scan, mesenteric mass 0.5 x 0.5 cm, background uptake only.

[0023] Detailed Description definition As used herein, the term "immunoglobulin" refers to a class of structurally related glycoproteins consisting of two pairs of polypeptide chains, one pair of low molecular weight light (L) chains and one pair of heavy (H) chains, all four interconnected by disulfide bonds. The structure of immunoglobulins is well characterized [see, e.g., Fundamental Immunology Ch. 7 (Paul, W., ed., 2nd ed., Raven Press, NY (1989)]. Briefly, each heavy chain typically comprises a heavy chain variable region (referred to herein as VH or VH) that encodes a heavy chain variable region (VH or VH). H and a heavy chain constant region (abbreviated as CH or C herein) HThe heavy chain constant region is typically composed of three domains, namely CH1, CH2 and CH3. The hinge region is the region between the CH1 and CH2 domains of the heavy chain and is highly flexible. Disulfide bonds in the hinge region are part of the interaction between the two heavy chains in an IgG molecule. Each light chain typically contains a light chain variable region (herein referred to as VL or V L and a light chain constant region (abbreviated as CL or C herein). L The light chain constant region is typically composed of one domain, CL. The VH and VL regions are further subdivided into hypervariable regions (or highly variable regions that may be hypervariable in the shape and / or sequence of structurally defined loops), also called complementarity-determining regions (CDRs), which are interspersed with more highly conserved regions called framework regions (FRs). Each VH and VL is typically composed of three CDRs and four FRs, arranged from the amino terminus to the carboxy terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4 (see also Chothia and Lesk J Mol Biol 1987;196:90117). Unless otherwise indicated or contradicted by the context, CDR sequences herein are identified according to the IMGT conventions (Brochet X., Nucl Acids Res 2008;36:W503-508; Lefranc MP., Nucl Acids Res 1999;27:209-12; www.imgt.org / ). Unless otherwise indicated or contradicted by the context, references to amino acid positions in the constant region are according to EU numbering (Edelman et al., PNAS. 1969;63:78-85; Kabat et al., Sequences of Proteins of Immunological Interest, Fifth Edition. 1991 NIH Publication No. 91-3242). For example, SEQ ID NO: 15 represents amino acid positions 118 to 447 according to EU numbering in the IgG1 heavy chain constant region.

[0024] As used herein, the phrase "amino acid corresponding to position ..." refers to the amino acid position number in the human IgG1 heavy chain. Corresponding amino acid positions in other immunoglobulins can be found by alignment with human IgG1. Thus, an amino acid or segment in one sequence that "corresponds" to an amino acid or segment in another sequence means an amino acid or segment that, when aligned with said other amino acid or segment using a standard sequence alignment program (e.g., ALIGN, ClustalW, or the like), typically with default settings, has at least 50%, at least 80%, at least 90%, or at least 95% identity to the human IgG1 heavy chain. It is within the capabilities of one skilled in the art to align sequences or segments within sequences and thereby determine the corresponding positions within the sequences for the amino acid positions according to the invention.

[0025] As used herein in the context of the present invention, the term "antibody" (Ab) refers to an immunoglobulin molecule capable of specifically binding to an antigen under typical physiological conditions and having a significant half-life, e.g., at least about 30 minutes, at least about 45 minutes, at least about 1 hour, at least about 2 hours, at least about 4 hours, at least about 8 hours, at least about 12 hours, about 24 hours or more, about 48 hours or more, about 3 days, 4 days, 5 days, 6 days, 7 days or more, or any other suitable functionally defined period (e.g., a period sufficient to induce, promote, enhance, and / or modulate a physiological response associated with antibody binding to an antigen and / or a period sufficient for the antibody to recruit effector activity). The variable regions of the heavy and light chains of an immunoglobulin molecule contain binding domains that interact with the antigen. The term antibody also includes polyclonal antibodies, monoclonal antibodies (mAbs), antibody-like polypeptides, chimeric antibodies, and humanized antibodies, unless otherwise indicated. The generated antibody can be of any isotype.

[0026] The term "antibody fragment" or "antigen-binding fragment" as used herein refers to a fragment of an immunoglobulin molecule that retains the ability to specifically bind to an antigen and that can be produced by any known technique, such as enzymatic cleavage, peptide synthesis, and recombinant techniques. Examples of antibody fragments include: (i) Fab' or Fab fragments, i.e., monovalent fragments consisting of the VL, VH, CL, and CH1 domains, or monovalent antibodies as described in WO2007059782 (Genmab); (ii) F(ab')2 fragments, i.e., bivalent fragments comprising two Fab fragments linked by a disulfide bridge in the hinge region, (iii) Fd fragments, consisting essentially of the VH and CH1 domains; (iv) Fv fragments, consisting essentially of the VL and VH domains of a single arm of an antibody; (v) dAb fragments, consisting essentially of the VH domain (Ward et al., Nature 1989;341:54446) [also called domain antibodies (Holt et al.; Trends Biotechnol 2003;21:484-90)]; (vi) camelid antibodies or nanobodies (Revets et al.; Expert Opin Biol Ther 2005;5:111-24); and (vii) isolated complementarity-determining regions (CDRs). Furthermore, although the two domains of the Fv fragment, i.e., VL and VH, are encoded by separate genes, they can be joined using recombinant methods by a synthetic linker that pairs the VL and VH domains into a monovalent molecule [known as a single-chain antibody or single-chain Fv (scFv); see, e.g., Bird et al., Science 1988; 242 :42326 and Huston et al., PNAS 1988;85:587-983]. Unless otherwise indicated or clearly contradicted by context, such single-chain antibodies are included in the term antibody fragment.

[0027] As used herein, the term "antibody binding region" or "antigen-binding region" refers to a region comprising both a VH region and a VL region that interacts with an antigen. As used herein, the term "antibody" refers not only to monospecific antibodies but also to multispecific antibodies comprising multiple (e.g., two or more, e.g., three or more) different antigen-binding regions. Unless otherwise indicated or clearly contradicted by context, the term "antigen-binding region" includes fragments of antibodies that are antigen-binding fragments, i.e., antibody fragments that retain the ability to specifically bind to an antigen.

[0028] As used herein, the term "isotype" refers to the immunoglobulin class (e.g., IgG1, IgG2, IgG3, IgG4, IgD, IgA, IgE, or IgM) encoded by heavy chain constant region genes. When a particular isotype (e.g., IgG1) is referred to, the term is not limited to a particular isotype sequence (e.g., a particular IgG1 sequence) but is used to indicate that the antibody is closer in sequence to that isotype (e.g., IgG1) than to other isotypes. Thus, for example, an IgG1 antibody may be a sequence variant of a naturally occurring IgG1 antibody, which may contain mutations in the constant region.

[0029] As used herein, the term "bispecific antibody" or "bs" or "bsAb" refers to an antibody that has two different antigen-binding regions defined by different antibody sequences. Bispecific antibodies can be of any form.

[0030] As used herein, the terms "half molecule," "Fab arm," and "arm" refer to one heavy-light chain pair.

[0031] When a bispecific antibody is described as comprising a half-molecule antibody "derived from" a first parent antibody and a half-molecule antibody "derived from" a second parent antibody, the term "derived from" indicates that the bispecific antibody has been produced by recombining half molecules from each of said first and second parent antibodies into the resulting bispecific antibody by any known method. In this context, "recombinant" is not intended to be limited to any particular recombination method, and thus includes all of the methods of producing bispecific antibodies described herein, such as recombination by half-molecule exchange (also known as "controlled Fab arm exchange"), as well as recombination at the nucleic acid level and / or by co-expression of two half-molecules in the same cell.

[0032] The term "full length" as used herein in the context of antibodies means that the antibody is not a fragment and contains all of the domains of a particular isotype that are normally found in nature for that isotype (e.g., the VH, CH1, CH2, CH3, hinge, VL, and CL domains of an IgG1 antibody). Full-length antibodies can be engineered. An example of a "full-length" antibody is epcolitamab.

[0033] As used herein, the term "Fc region" refers to the region of an antibody that consists of the Fc sequences of two immunoglobulin heavy chains, the Fc sequences including at least the hinge region, CH2 domain, and CH3 domain.

[0034] As used herein, the term "heterodimeric interaction between a first CH3 region and a second CH3 region" refers to the interaction between a first CH3 region and a second CH3 region in a first CH3 / second CH3 heterodimeric protein.

[0035] As used herein, the term "homodimeric interaction between a first CH3 region and a second CH3 region" refers to an interaction between a first CH3 region and another first CH3 region in a first CH3 / first CH3 homodimeric protein, and an interaction between a second CH3 region and another second CH3 region in a second CH3 / second CH3 homodimeric protein.

[0036] The term "binding" as used herein in the context of antibody binding to a given antigen typically refers to a binding of about 10, as measured, for example, by BioLayer Interferometry (BLI) technology on an Octet HTX instrument using the antibody as the ligand and the antigen as the analyte. -6 M or less, e.g. 10 -7 M or less, for example, about 10 -8 M or less, for example, about 10 -9 M or less, about 10 -10 M or less or about 10 -11 K below M D where the antibody has a K of 1.0 or greater for binding to a non-specific antigen other than the given antigen or a closely related antigen (e.g., BSA, casein). D at least 10 times lower, such as at least 100 times lower, such as at least 1,000 times lower, such as at least 10,000 times lower, such as at least 100,000 times lower, D binds to a given antigen with an affinity corresponding to the binding K D The amount of decrease is the antibody K D Because it depends on the antibody's K D If the K of binding to the antigen is very low, D is the K for nonspecific antigen binding D The amount reduced from can be at least 10,000-fold (ie, the antibody is highly specific).

[0037] As used herein, "K D The term "Affinity" (M) refers to the dissociation equilibrium constant for a particular antibody-antigen interaction. As used herein, affinity and K Dis inversely related to the K D is intended to mean that a lower affinity corresponds to a higher K D is intended to mean

[0038] As used herein, the term "isolated antibody" ("isolated antibody") refers to an antibody that is substantially free of other antibodies having different antigen specificities. In a preferred embodiment, an isolated bispecific antibody that specifically binds to CD20 and CD3 is also substantially free of monospecific antibodies that specifically bind to CD20 or CD3.

[0039] As used herein, the term "CD3" refers to the human cluster of differentiation 3 protein, which is composed of four distinct chains that are part of a T-cell co-receptor protein complex. CD3 is also present in other species, and therefore, unless contradicted by context, the term "CD3" is not limited to human CD3. In mammals, the complex contains the CD3γ (gamma) chain (human CD3γ chain UniProtKB / Swiss-Prot No. P09693 or cynomolgus monkey CD3γ UniProtKB / Swiss-Prot No. Q95LI7), the CD3δ (delta) chain (human CD3δ UniProtKB / Swiss-Prot No. P04234 or cynomolgus monkey CD3δ UniProtKB / Swiss-Prot No. Q95LI8), two CD3ε (epsilon) chains (human CD3ε UniProtKB / Swiss-Prot No. P07766, SEQ ID NO: 28); cynomolgus monkey CD3ε UniProtKB / Swiss-Prot No. Q95LI5; or rhesus monkey CD3ε UniProtKB / Swiss-Prot No. G7NCB9), and the CD3ζ (zeta) chain (human CD3ζ (UniProtKB / Swiss-Prot No P20963, cynomolgus monkey CD3ζ UniProtKB / Swiss-Prot No Q09TK0). These chains associate with a molecule known as the T cell receptor (TCR) to generate an activation signal in T lymphocytes. Together, the TCR and CD3 molecules make up the TCR complex.

[0040] As used herein, the term "CD3 antibody" or "anti-CD3 antibody" refers to an antibody that specifically binds to the antigen CD3, particularly human CD3ε (epsilon).

[0041] The term "human CD20" or "CD20" refers to human CD20 (UniProtKB / Swiss-Prot No. P11836, SEQ ID NO: 29) and includes any variant, isoform, and species homolog of CD20 naturally expressed by cells, including tumor cells, or expressed on cells transfected with the CD20 gene or cDNA. Species homologs include rhesus monkey CD20 (Macaca mulatta; UniProtKB / Swiss-Prot No. H9YXP1) and cynomolgus monkey CD20 (Macaca fascicularis; UniProtKB No. G7PQ03).

[0042] As used herein, the term "CD20 antibody" or "anti-CD20 antibody" refers to an antibody that specifically binds to the antigen CD20, particularly human CD20.

[0043] As used herein, the term "CD3xCD20 antibody," "anti-CD3xCD20 antibody," "CD20xCD3 antibody," or "anti-CD20xCD3 antibody" refers to a bispecific antibody comprising two different antigen-binding regions, one of which specifically binds to the antigen CD20 and the other of which specifically binds to CD3.

[0044] As used herein, the term "DuoBody-CD3xCD20" refers to an IgG1 bispecific CD3xCD20 antibody comprising a first heavy and light chain pair set forth in SEQ ID NO:24 and SEQ ID NO:25, respectively, and a second heavy and light chain pair set forth in SEQ ID NO:26 and SEQ ID NO:27. The first heavy and light chain pair comprises a region that binds to human CD3ε (epsilon), and the second heavy and light chain pair comprises a region that binds to human CD20. The first binding region comprises the VH and VL sequences set forth in SEQ ID NO:6 and SEQ ID NO:7, and the second binding region comprises the VH and VL sequences set forth in SEQ ID NO:13 and SEQ ID NO:14. This bispecific antibody can be produced as described in WO 2016 / 110576.

[0045] Also provided herein are antibodies comprising functional variants of the heavy chain, light chain, VL region, VH region, or one or more CDRs of exemplary antibodies. A functional variant of the heavy chain, light chain, VL, VH, or CDR, used in the context of an antibody, still enables the antibody to retain at least a substantial proportion (at least about 90%, 95%, or more) of the functional characteristics of the "reference" and / or "parent" antibody, including affinity and / or specificity / selectivity for a particular epitope of CD20 and / or CD3, Fc inactivation, and PK parameters such as half-life, Tmax, Cmax. Such functional variants typically retain significant sequence identity to the parent antibody and / or have substantially similar lengths of the heavy and light chains. The percent identity between two sequences is a function of the number of identical positions shared by the sequences [i.e., % homology = number of identical positions / total number of positions × 100], taking into account the number of gaps and the length of each gap that need to be introduced for optimal alignment of the two sequences. Percent identity between two nucleotide or amino acid sequences can be determined, for example, using the algorithm of E. Meyers and W. Miller, Comput. Appl. Biosci. 4, 11-17 (1988), incorporated into the ALIGN program (version 2.0), using a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4. Percent identity between two amino acid sequences can also be determined using the algorithm of Needleman and Wunsch, J. Mol. Biol. 48, 444-453 (1970). Exemplary variants include variants that differ from the heavy and / or light chain, VH and / or VL and / or CDR regions of a parent antibody sequence primarily by conservative substitutions, for example, 10, e.g., 9, 8, 7, 6, 5, 4, 3, 2 or 1 of the substitutions in the variant can be conservative amino acid residue substitutions.

[0046] Conservative substitutions may be defined by substitutions within the amino acid classes shown in the table below. [Table 1]

[0047] Unless otherwise indicated, the following nomenclature is used to indicate mutations: i) substitution of an amino acid at a given position is denoted, for example, K409R, which means substitution of lysine at position 409 with arginine; and ii) for specific variants, specific three-letter or one-letter codes (including the codes Xaa and X, which indicate any amino acid residue) are used. Thus, substitution of lysine at position 409 with arginine is denoted as K409R, and substitution of lysine at position 409 with any amino acid residue is denoted as K409X. In the case of deletion of lysine at position 409, it is denoted as K409R. * is shown as:

[0048] As used herein, the term "humanized antibody" refers to a genetically engineered non-human antibody containing a non-human variable domain and a human antibody constant domain that have been modified to have a high level of sequence homology to the human variable domain. This can be achieved by grafting the six non-human antibody CDRs that together form the antigen-binding site onto homologous human acceptor framework regions (FRs) (see WO 92 / 22653 and EP 0 629 240). To fully reconstitute the binding affinity and specificity of the parent antibody, it may be necessary to replace (backmutate) framework residues from the parent antibody (i.e., non-human antibody) with human framework regions. Structural homology modeling can help identify amino acid residues within the framework regions that are important for the binding properties of the antibody. Thus, a humanized antibody can contain non-human CDR sequences, primarily human framework regions (optionally containing one or more amino acid backmutations to non-human amino acid sequences), and a fully human constant region. The VH and VL of the CD3 arm used herein in DuoBody-CD3xCD20 correspond to humanized antigen-binding regions. Additional amino acid modifications, not necessarily back mutations, can be applied, if desired, to obtain humanized antibodies with preferred properties, such as affinity and biochemical properties.

[0049] As used herein, the term "human antibody" refers to an antibody having variable and constant regions derived from human germline immunoglobulin sequences. Human antibodies may contain amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo). However, the term "human antibody" as used herein is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. The VH and VL of the CD20 arms used in DuoBody-CD3xCD20 represent human antigen-binding regions. The human monoclonal antibodies of the invention can be produced by a variety of techniques, including conventional monoclonal antibody methods, such as the standard somatic cell hybridization method of Kohler and Milstein, Nature 256:495 (1975). Although somatic cell hybridization is preferred, in principle, other techniques for producing monoclonal antibodies can be used, such as viral or oncogenic transformation of B lymphocytes or phage display techniques using human antibody gene libraries. A suitable animal system for generating hybridomas secreting human monoclonal antibodies is the mouse system. Hybridoma production in mice is a well-established procedure. Immunization protocols and techniques for isolating immunized splenocytes for fusion are known in the art. Fusion partners (e.g., mouse myeloma cells) and fusion procedures are also known. Thus, human monoclonal antibodies can be generated using, for example, transgenic or transchromosomal mice or rats carrying parts of the human immune system, rather than the mouse or rat system. Thus, in one embodiment, human antibodies are obtained from transgenic animals, such as mice or rats, that have human germline immunoglobulin sequences instead of the animal's immunoglobulin sequences.In such embodiments, the antibody is derived from human germline immunoglobulin sequences introduced into the animal, with the final antibody sequence being the result of further modification by somatic hypermutation and affinity maturation by the endogenous animal antibody machinery (see, e.g., Mendez et al. Nat Genet 1997;15:146-56). The VH and VL regions of the CD20 arms used in DuoBody-CD3xCD20 represent human antigen-binding regions.

[0050] As used herein, the term "biosimilar" (e.g., a biosimilar of an approved reference product / biological drug) refers to a biological product that is similar to the reference product based on data from: (a) analytical studies demonstrating that the biological product is highly similar to the reference product, with minor differences in clinically inactive components; (b) animal studies (including toxicity assessments); and / or (c) clinical studies (including immunogenicity and pharmacokinetic or pharmacodynamic assessments) sufficient to demonstrate safety, purity, and efficacy (e.g., the absence of clinically significant differences between the biological product and the reference product with respect to the product's safety, purity, and efficacy) under one or more appropriate conditions of use for which the reference product is approved and intended for use and for which approval is sought. In some embodiments, a biosimilar biological product and a reference product utilize the same mechanism of action (but only to the extent that the mechanism of action is known for the reference product) for the conditions of use specified, recommended, or suggested in the proposed labeling for the biological product. In some embodiments, the conditions of use specified, recommended, or suggested in the proposed labeling for the biological product have already been approved for the reference product. In some embodiments, the route of administration, dosage form, and / or strength of the biological product is the same as that of the reference product. A biosimilar can be, for example, a currently known antibody that has the same primary amino acid sequence as a commercially available antibody, but can be produced in a different cell type or by a different manufacturing, purification, or formulation method.

[0051] As used herein, the term "reducing conditions" or "reducing environment" refers to conditions or circumstances in which a substrate (in this case, a cysteine ​​residue in the hinge region of an antibody) is more likely to be reduced than oxidized.

[0052] The term "recombinant host cell" (or simply "host cell"), as used herein, is intended to mean a cell into which an expression vector (e.g., an expression vector encoding an antibody described herein) has been introduced. Recombinant host cells include, for example, transfectomas such as CHO, CHO-S, HEK, HEK293, HEK-293F, Expi293F, PER.C6 or NS0 cells, and lymphocytic cells.

[0053] As used herein, "Richter's syndrome" or "Richter's transformation" are used interchangeably to refer to the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma. Richter's syndrome occurs in the setting of CLL or SLL (Swerdlow et al., 2017; WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues, International Agency for Research on Cancer, Lyon, France) and occurs in approximately 10% to 15% of CLL patients. In the majority of cases, CLL progresses to diffuse large B-cell lymphoma (DLBCL), which maintains a clonal relationship with the original leukemia stage, while the remaining patients develop Hodgkin's lymphoma variant 2. Survival rates for patients with RS are generally poor, with patients with selective chromosomal abnormalities or clonally related to CLL experiencing the worst prognosis and outcomes (Allan and Furman, 2019; Int J Hematol Oncol, 7(4), p. IJH09, Falchi et al., 2014; Blood, 123(18), pp. 2783-27903).

[0054] Several genetic and immune factors may contribute to this transformation. Recently, additional risk factors have been identified, such as TP53 disruption, NOTCH1 mutation, CDKN2A loss, and MYC activation (Rossi et al., 2018; Blood, 131(25), pp. 2761-2772, Chigrinova et al., 2013; Blood, 122(15), pp. 2673-2682, Fabbri et al., 2013; J Exp Med, 210(11)13), pp. 2273-2288, Parikh et al., 2014; Blood, 123(11), pp. 1647-1657). Furthermore, biased use of subset 8 V4-39 variant immunoglobulin genes increases the risk of developing RS by 24-fold (Parikh et al., 2013; Br J Haematol, 162(6), pp. 774-782; Rossi et al., 2009, Clin Cancer Res, 15(13), pp. 4415-4422), suggesting an inductive role of B cell receptor (BCR) signaling in transformation. Overall, the molecular profile of RS is heterogeneous, lacks a unifying lesion, and does not overlap with the genetic features of de novo DLBCL (Fabbri et al., 2013; J Exp Med, 210(11)13, pp. 2273-2288). Deregulation of the underlying transcriptional programs and signaling pathways may contribute to the aggressive clinical phenotype of RS (Allan and Furman, 2019; Int J Hematol Oncol, 7(4), p. IJH09).

[0055] The term "treatment" refers to the administration of an effective amount of a therapeutically active antibody described herein for the purpose of alleviating, ameliorating, preventing, or eradicating (curing) a symptom or condition, such as CLL. Treatment may result in a complete response (CR), partial response (PR), or stable disease (SD), as defined, for example, by the Lugano criteria (Cheson et al., 2014), as set forth in Table 2.

[0056] Treatment can be continued, for example, until progressive disease (PD) or unacceptable toxicity occurs.

[0057] As used herein, the terms "administer" or "administration" refer to the physical introduction of a composition (or formulation) containing a therapeutic agent into a subject using any of a variety of methods and delivery systems known to those of skill in the art. Preferred routes of administration of the antibodies described herein include intravenous, intraperitoneal, intramuscular, subcutaneous, intraspinal, or other parenteral routes of administration, such as injection or infusion. As used herein, the term "parenteral administration" refers to any administration method other than enteral and nontopical administration, usually by injection, and includes, but is not limited to, intravenous, intraperitoneal, intramuscular, intraarterial, intrathecal, intralymphatic, intralesional, intracapsular, intraorbital, intracardiac, intradermal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural, and intrasternal injection and infusion, as well as in vivo electroporation. Alternatively, the therapeutic substances described herein can be administered parenterally, for example, via a topical, epidermal, or mucosal administration route, such as intranasal, oral, intravaginal, intrarectal, sublingual, or topical route. Administration can be, for example, once, multiple times, and / or over one or more extended periods. In the methods described herein, the bispecific antibody (e.g., epcolitamab) is administered subcutaneously. Other substances used in combination with the bispecific antibody, for example, for the prevention of cytokine release syndrome or tumor lysis syndrome (TLS), can be administered via other routes, such as intravenously or orally.

[0058] The terms "effective amount" or "therapeutically effective amount" refer to an amount effective, at the necessary dosage and for the necessary duration, to achieve the desired therapeutic result. For example, dosages set forth herein for a bispecific antibody (e.g., epcolitamab) in the range of 12 to 60 mg administered subcutaneously may be defined as such an "effective amount" or "therapeutically effective amount." A therapeutically effective amount of an antibody may vary depending on factors such as the individual's condition, age, sex, and weight, as well as the ability of the antibody to elicit a desired response in the individual. A therapeutically effective amount is also an amount in which any toxic or adverse effects of the antibody or antibody portion are outweighed by the therapeutically beneficial effects. In some embodiments, patients treated with the methods described herein exhibit improved ECOG performance status. A therapeutically effective amount or dosage of a drug includes a "prophylactically effective amount" or "prophylactically effective dose," which is any amount of a drug that, when administered alone or in combination with another therapeutic agent, to a subject at risk of developing or recurring a disease or disorder (e.g., cytokine release syndrome), inhibits the development or recurrence of the disease.

[0059] As used herein, the term "inhibiting the proliferation (growth)" of a tumor includes any measurable reduction in tumor proliferation (growth), for example, at least about 10%, e.g., at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 99% or 100% tumor growth inhibition.

[0060] As used herein, the term "subject" refers to a human patient, for example, a human patient with Richter's syndrome. The terms "subject" and "patient" are used interchangeably herein.

[0061] The term "buffer" as used herein refers to a pharmaceutically acceptable buffer. The term "buffer" encompasses substances that maintain the pH of a solution within an acceptable range, including, but not limited to, acetate, histidine, TRIS (registered trademark) (tris(hydroxymethyl)aminomethane), citrate, succinate, glycolate, and the like. Generally, a "buffer" as used herein has a pKa and buffering capacity suitable for a pH range of about 5 to about 6 (preferably about 5.5).

[0062] As used herein, "progressive disease" or "PD" refers to a state in which one or more indicators of lymphoma indicate that the disease is progressing despite treatment. In some embodiments, progressive disease is defined based on the Lugano criteria (Cheson et al., 2014) as shown in Table 2.

[0063] As used herein, a "surfactant" is a compound typically used in pharmaceutical formulations to prevent drug adsorption and / or aggregation on surfaces. Furthermore, surfactants reduce the surface tension (or interfacial tension) between two liquids or between a liquid and a solid. For example, exemplary surfactants can significantly reduce surface tension when present at very low concentrations (e.g., 5% w / v or less, e.g., 3% w / v or less, e.g., 1% w / v or less, e.g., 0.4% w / v or less, e.g., less than 0.1% w / v, e.g., 0.04% w / v). Surfactants are amphiphilic, meaning that they are typically composed of both hydrophilic and hydrophobic or lipophilic groups and can therefore form micelles or similar self-assembled structures in aqueous solution. Known surfactants for pharmaceutical use include glycerol monooleate, benzethonium chloride, sodium docusate, phospholipids, polyethylene alkyl ethers, sodium lauryl sulfate, and tricaprylin (anionic surfactants); benzalkonium chloride, citrimide, cetylpyridinium chloride, and phospholipids (cationic surfactants); and alpha tocopherol, glycerol monooleate, myristyl alcohol, phospholipids, poloxamer, polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene stearate, polyoxylhydroxystearate, polyoxylglycerides, polysorbates such as polysorbate 20 or polysorbate 80, propylene glycol dilaurate, propylene glycol monolaurate, sorbitan esters sucrose palmitate, sucrose stearate, tricaprylin, and TPGS (nonionic and zwitterionic surfactants).

[0064] As used herein, a "diluent" refers to a pharmaceutically acceptable (safe and non-toxic for administration to humans) diluent useful for preparing a diluent of a pharmaceutical composition or formulation (the terms "composition" and "formulation" are used interchangeably herein). Preferably, such a diluent of the composition dilutes only the antibody concentration, and does not dilute the buffer and stabilizer. Thus, in one embodiment, the diluent contains the same concentrations of buffer and stabilizer as present in the pharmaceutical composition of the present invention. Further exemplary diluents include sterile water, bacteriostatic water for injection (BWFI), a pH buffered solution, preferably acetate buffer, sterile saline, Ringer's solution, or dextrose solution. In one embodiment, the diluent comprises or consists essentially of acetate buffer and sorbitol.

[0065] As used herein, "about" means ±10% of the specified value.

[0066] Treatment regimens for Richter's syndrome Richter's syndrome (RS), also known as Richter's transformation, is a rare complication of chronic lymphocytic leukemia (CLL) and / or small lymphocytic lymphoma (SLL). It is characterized by the sudden transformation of CLL / SLL into a significantly more aggressive form of large cell lymphoma. In most cases, the usually slow-growing or indolent CLL transforms into a common form of non-Hodgkin's lymphoma (NHL) known as diffuse large B-cell lymphoma (DLBCL). Rare cases transform into Hodgkin's lymphoma (HL) / Hodgkin's disease (HD), and several types of T-cell lymphoma have also been reported.

[0067] Although the exact cause of Richter's syndrome remains unknown, certain factors are thought to increase the risk of developing RS in patients already diagnosed with CLL / SLL. These risk factors include certain inherited genetic characteristics (e.g., BCL-2, CD38, and LRP4 genotypes) and certain gene mutations. For example, patients with chromosomal deletions of 11q and 17p, unmutated IGVH genes, NOTCH-1 mutations, shortened telomere length, elevated levels of zeta-associated protein (ZAP-70), beta-2 microglobulin (B2M), and CD38, and / or advanced-stage disease (Rai stage III-IV with lymph nodes >3 cm) at the time of initial CLL diagnosis are all thought to be at greater risk of developing RS.

[0068] Richter's syndrome is characterized by sudden clinical deterioration. Currently available therapies have shown limited responses and have unsatisfactory safety profiles. Median overall survival ranges from several months to approximately one year. In the absence of an established standard of care, there is a need for therapies with novel modes of action that produce durable responses with a tolerable safety profile. One such therapy is treating patients with RS with a bispecific antibody that binds to CD3 and CD20 ("anti-CD3xCD20 antibody").

[0069] Thus, in one embodiment, (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that comprises a variable heavy (VH) region and a variable light (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region and comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 14.

[0023] Provided herein is a method for treating Richter's syndrome in a human subject, comprising administering to the subject (e.g., subcutaneously) an effective amount of a bispecific antibody comprising:

[0070] Preferably, the bispecific antibody is administered at a dose ranging from 12 to 60 mg in a 28-day cycle.

[0071] In some embodiments, the bispecific antibody is a full-length antibody. In some embodiments, the bispecific antibody is an antibody with an inactive Fc region. In some embodiments, the bispecific antibody is a full-length antibody with an inactive Fc region.

[0072] In some embodiments, the bispecific antibody is administered at a dose of 12 mg (or about 12 mg). In some embodiments, the bispecific antibody is administered at a dose of 24 mg (or about 24 mg). In some embodiments, the bispecific antibody is administered at a dose of 48 mg (or about 48 mg). In some embodiments, the bispecific antibody is administered at a dose of 60 mg (or about 60 mg).

[0073] With respect to a 12-60 mg dose or any other specified dose of a bispecific antibody administered, this amount is understood to mean the amount of bispecific antibody corresponding to a full-length antibody, such as epcolitamab, as defined in the Examples section. Thus, administering a 24 mg dose of a bispecific antibody can be referred to as administering a dose of the bispecific antibody described herein, in which case the dose corresponds to a 24 mg dose of epcolitamab. For example, if the antibody used is substantially different in molecular weight from the molecular weight of a full-length antibody, such as epcolitamab, one skilled in the art can easily determine the amount of antibody to be administered. For example, the amount of antibody can be calculated by dividing the molecular weight of the antibody by the weight of a full-length antibody, such as epcolitamab, and multiplying the result by a specific dose described herein. To the extent that a bispecific antibody (e.g., a functional variant of DuoBody-CD3xCD20) has properties highly similar to DuoBody-CD3xCD20 in terms of plasma half-life, Fc inactivation and / or binding properties to CD3 and CD20, i.e., CDR and epitope binding properties, such an antibody is suitable for use in the methods provided herein at the doses described for full-length antibodies such as epcolitamab.

[0074] In one embodiment, the bispecific anti-CD3xCD20 antibody is administered at a dose ranging from 12 mg to 60 mg. In some embodiments, the bispecific antibody is administered at a dose of 12 mg or about 12 mg. In some embodiments, the bispecific antibody is administered at a dose of 24 mg or about 24 mg. In some embodiments, the bispecific antibody is administered at a dose of 48 mg or about 48 mg. In some embodiments, the bispecific antibody is administered at a dose of 60 mg or about 60 mg.

[0075] In some embodiments, the bispecific antibody dose is administered once per week in a 28-day cycle (weekly dosing). In some embodiments, the weekly dosing occurs in 2.5 28-day cycles (i.e., 10 times). In one embodiment, the dose is administered in 2.5 28-day cycles (i.e., 10 times; on days 15 and 22 of cycle 1, and days 1, 8, 15, and 22 of cycles 2 and 3). In some embodiments, after the weekly dosing, the dosing interval of the bispecific antibody may be reduced to once every two weeks (biweekly dosing). In some embodiments, such biweekly dosing may occur in six 28-day cycles (i.e., 12 times). In some embodiments, after the biweekly dosing, the dosing interval of the bispecific antibody may be reduced to once every four weeks. In one embodiment, the once every four weeks administration can be administered over an extended period of time, for example, at least one 28-day cycle (i.e., at least one 28-day cycle), at least two cycles, at least three cycles, at least four cycles, at least five cycles, at least six cycles, at least seven cycles, at least eight cycles, at least nine cycles, at least ten cycles, at least 11 cycles, at least 12 cycles, at least 13 cycles, at least 14 cycles, at least 15 cycles, at least 16 cycles, at least 17 cycles, or 1 to 20 cycles, 1 to 19 cycles, 1 to 18 cycles, 1 to 17 cycles, 1 to 16 cycles, 1 to 15 cycles, 1 to 14 cycles, 1 to 13 cycles, 1 to 12 cycles, 1 to 10 cycles, 1 to 5 cycles, 5 to 20 cycles, 5 to 15 cycles, or 5 to 10 cycles. In some embodiments, epcolitamab is administered every 4 weeks until disease progression (e.g., as defined by the Lugano criteria (Cheson et al., 2014) shown in Table 2) or unacceptable toxicity. In one embodiment, weekly doses are administered in cycles 1-3 (which may include priming and intermediate doses, as described below), biweekly doses are administered in cycles 4-9, and once every 4 weeks from cycle 10 onwards.

[0076] It is understood that the doses referred to herein may also be referred to as full or flat doses in the above scenarios, for example, when the weekly dose, biweekly dose, and / or every four weeks dose are at the same level. Thus, if a 48 mg dose is selected, the same 48 mg dose is preferably administered in each weekly administration, each biweekly administration, and each every four weeks administration. Before administering a dose, a priming dose, or a priming dose and one or more subsequent intermediate (second priming) doses may be administered. This may be advantageous because it may help reduce the risk and severity of cytokine release syndrome (CRS), a side effect that may occur during treatment with the bispecific anti-CD3×CD20 antibody described herein. Such a priming dose, or the priming dose and the intermediate dose, is a lower dose than a flat or full dose.

[0077] Thus, in some embodiments, a priming dose of bispecific antibody may be administered prior to the administration of the 12-60 mg weekly dose. In one embodiment, the priming dose is administered two weeks prior to the administration of the first weekly dose of 12-60 mg in Cycle 1. The priming dose may be in the range of 20-2000 μg (0.02 mg-2 mg), e.g., in the range of 50-1000 μg (0.05 mg-1 mg) or in the range of 70-350 μg (0.07 mg-0.35 mg). The priming dose can be, for example, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 350, 400, 450, 500, 600, 700, 800, 900, or 1000 μg, or about 80, about 100, about 120, about 140, about 160, about 180, about 200, about 220, about 240, about 260, about 280, about 300, about 320, about 350, about 400, about 450, about 500, about 600, about 700, about 800, about 900, or about 1000 μg. In preferred embodiments, the priming dose ranges from 50 μg to 350 μg (0.05 mg to 0.35 mg, respectively). In more preferred embodiments, the priming dose is 160 μg (0.16 mg) or about 160 μg (about 0.16 mg). In the most preferred embodiment, the priming dose is 160 μg (0.16 mg) or about 160 μg (about 0.16 mg) of full-length bispecific antibody.

[0078] In some embodiments, one or more intermediate doses of the bispecific antibody are administered after the priming dose and before the first weekly dose of 12-60 mg. In one embodiment, the priming dose is administered on day 1, and the intermediate dose is administered on day 8, prior to the administration of the first weekly doses of 12-60 mg on days 15 and 22 of cycle 1. That is, the priming dose is administered one week before the administration of the intermediate dose (i.e., day 1 of cycle 1), and the intermediate dose is administered one week before the administration of the first weekly dose of 12-60 mg (day 8 of cycle 1). The one or more intermediate doses are selected from the range between the priming dose and the flat or full dose. For example, the one or more intermediate doses can be in the range of 200-8000 μg (0.2-8 mg), e.g., 400-4000 μg (0.4-4 mg) or 600-2000 μg (0.6-2 mg). Intermediate doses can be, for example, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, or 1600 μg, or about 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, or 1600 μg. In preferred embodiments, intermediate doses range from 600 μg to 1200 μg (0.6 mg to 1.2 mg, respectively). Currently preferred embodiments use intermediate doses that are 800 μg (0.8 mg) or about 800 μg (0.8 mg). The most preferred embodiment uses an intermediate dose of at or about 800 μg (0.8 mg) of full-length bispecific antibody.

[0079] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0080] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In Cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 12 to 60 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0081] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0082] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 12 mg or about 12 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 12 mg or about 12 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg or about 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg or about 12 mg is administered on day 1.

[0083] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 12 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 12 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg is administered on day 1.

[0084] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 12 mg or about 12 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 12 mg or about 12 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg or about 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg or about 12 mg is administered on day 1.

[0085] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 24 mg or about 24 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 24 mg or about 24 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg or about 24 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 24 mg or about 24 mg is administered on Day 1.

[0086] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In Cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 24 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 24 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg was administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 24 mg is administered on day 1.

[0087] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 24 mg or about 24 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 24 mg or about 24 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg or about 24 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 24 mg or about 24 mg is administered on Day 1.

[0088] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 48 mg or about 48 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 48 mg or about 48 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg or about 48 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 48 mg or about 48 mg is administered on Day 1.

[0089] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In Cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 48 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 48 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg was administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 48 mg is administered on day 1.

[0090] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 48 mg or about 48 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 48 mg or about 48 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg or about 48 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 48 mg or about 48 mg is administered on Day 1.

[0091] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 60 mg or about 60 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 60 mg or about 60 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg or about 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg or about 60 mg is administered on day 1.

[0092] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 60 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg is administered on day 1.

[0093] In some embodiments, the bispecific antibody is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 60 mg or about 60 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 60 mg or about 60 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg or about 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg or about 60 mg is administered on day 1.

[0094] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) In cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0095] In some embodiments, the bispecific antibody is epcolitamab, which is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 12 to 60 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0096] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) In cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, administer the full dose of 12 to 60 mg on day 1.

[0097] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 12 mg or about 12 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 12 mg or about 12 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg or about 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg or about 12 mg is administered on day 1.

[0098] In some embodiments, the bispecific antibody is epcolitamab, which is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) in cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 12 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 12 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg is administered on day 1.

[0099] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 12 mg or about 12 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 12 mg or about 12 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 mg or about 12 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 12 mg or about 12 mg is administered on day 1.

[0100] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 24 mg or about 24 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 24 mg or about 24 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg or about 24 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 24 mg or about 24 mg is administered on Day 1.

[0101] In some embodiments, the bispecific antibody is epcolitamab, which is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In Cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 24 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 24 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg was administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 24 mg is administered on day 1.

[0102] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 24 mg or about 24 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 24 mg or about 24 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 24 mg or about 24 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 24 mg or about 24 mg is administered on Day 1.

[0103] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 48 mg or about 48 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 48 mg or about 48 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg or about 48 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 48 mg or about 48 mg is administered on Day 1.

[0104] In some embodiments, the bispecific antibody is epcolitamab, which is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In Cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 48 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 48 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg was administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 48 mg is administered on day 1.

[0105] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 48 mg or about 48 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 48 mg or about 48 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 48 mg or about 48 mg is administered on days 1 and 15; and d) In Cycle 10 and subsequent cycles, a full dose of 48 mg or about 48 mg is administered on Day 1.

[0106] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and a full dose of 60 mg or about 60 mg is administered on days 15 and 22; b) in cycles 2-3, a full dose of 60 mg or about 60 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg or about 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg or about 60 mg is administered on day 1.

[0107] In some embodiments, the bispecific antibody is epcolitamab, which is administered (e.g., subcutaneously) in a 28-day cycle, wherein: a) In cycle 1, a priming dose ranging from 0.05 to 0.35 mg is administered on day 1, an intermediate dose ranging from 0.6 to 1.2 mg is administered on day 8, and a full dose of 60 mg is administered on days 15 and 22; b) Cycles 2-3, full doses of 60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg is administered on day 1.

[0108] In some embodiments, the bispecific antibody is epcolitamab, which is administered subcutaneously in a 28-day cycle, wherein: a) in cycle 1, a priming dose of 160 μg is administered on day 1, an intermediate dose of 800 μg is administered on day 8, and full doses of 60 mg or about 60 mg are administered on days 15 and 22; b) in cycles 2-3, a full dose of 60 mg or about 60 mg is administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 60 mg or about 60 mg is administered on days 1 and 15; and d) In cycle 10 and subsequent cycles, a full dose of 60 mg or about 60 mg is administered on day 1.

[0109] In one embodiment, a priming dose of 80 μg and an intermediate dose of 800 μg are selected for days 1 and 8 of the first cycle, respectively. In some embodiments, a priming dose of 80 μg and an intermediate dose of 1200 μg are selected for days 1 and 8 of the first cycle, respectively. In some embodiments, a priming dose of 80 μg and an intermediate dose of 1600 μg are selected for days 1 and 8 of the first cycle, respectively. In some embodiments, a priming dose of 160 μg and an intermediate dose of 1200 μg are selected for days 1 and 8 of the first cycle, respectively. In some embodiments, a priming dose of 160 μg and an intermediate dose of 1600 μg are selected for days 1 and 8 of the first cycle, respectively.

[0110] In one embodiment, the subject has a clinical history of CLL / SLL with transformation to aggressive lymphoma, e.g., of the DLBCL subtype. In another embodiment, Richter's syndrome is a DLBCL subtype.

[0111] In one embodiment, the human subject has measurable disease as determined by both of the following: a) a fluorodeoxyglucose (FDG)-positron emission tomography (PET) CT scan showing a positive lesion consistent with an anatomic tumor site defined by CT (or MRI), and b) a CT scan (or MRI) with two or more clearly defined lesions / nodes with a long axis greater than 1.5 cm and a short axis greater than 1.0 cm, or one clearly defined lesion / node with a long axis greater than 2.0 cm and a short axis equal to or greater than 1.0 cm.

[0112] In some embodiments, the human subject has received at least one line of treatment before being treated with the methods described herein. For example, in one embodiment, the subject has received one prior line of treatment. In some embodiments, the subject has refractory and / or recurrent Richter's syndrome after receiving one prior anti-tumor therapy. Relapse may be defined as evidence of disease progression in a subject who previously achieved CR or PR for at least six months. Refractory disease may be defined as treatment failure (failure to achieve CR or PR) or progression within six months of the last treatment administration. In some embodiments, the subject has received three prior lines of treatment. In some embodiments, the subject has received more than three prior lines of treatment. In some embodiments, the subject has received one, two, three, or more prior lines of treatment. In some embodiments, the subject has received at least two prior lines of treatment. In one embodiment, the prior lines of treatment include systemic anti-tumor therapy.

[0113] In some embodiments, the subject has received one or more, eg, at least two, prior lines of treatment for chronic lymphocytic leukemia (CLL) and / or small lymphocytic lymphoma (SLL).

[0114] Previous lines of treatment for CLL and / or SLL may include, inter alia, chemoimmunotherapy.

[0115] In other embodiments, the previous line of treatment for CLL and / or SLL includes therapy using a targeted agent, e.g., a BCL2 inhibitor or a BTK inhibitor.

[0116] In yet additional embodiments, the previous line of treatment for CLL and / or SLL comprises CAR T cell therapy.

[0117] In some embodiments, the subject has received prior treatment for Richter's syndrome, e.g., i) rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); ii) rituximab in combination with dexamethasone, cytarabine, and cisplatin (R-DHAP); iii) Venetoclax in combination with rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH) have received prior treatment selected from the following:

[0118] In some embodiments, a subject treated according to the present invention achieves a complete or partial metabolic response.

[0119] In other embodiments, a subject treated in accordance with the present invention achieves a complete response, a partial response, or stable disease.

[0120] In another embodiment, the subject receives epcolitamab according to the present invention as a first line treatment for Richter's syndrome. In a further embodiment, the method according to the present invention is a first line treatment for Richter's syndrome.

[0121] According to these embodiments, subjects treated according to the present invention as a first line treatment for Richter's syndrome achieve a complete or partial metabolic response.

[0122] In other embodiments, when a subject is treated according to the present invention as a first line treatment for Richter's syndrome, the subject achieves a complete response, partial response, or stable disease.

[0123] In some embodiments, human subjects must have a clinical history of CLL / SLL with biopsy-proven transformation to aggressive lymphoma (i.e., DLBCL subtype). In some embodiments, human subjects are deemed ineligible for chemoimmunotherapy or refuse to undergo intensive chemotherapy based on the investigator's discretion.

[0124] In some embodiments, human subjects must have measurable disease as determined by both of the following: a) a fluorodeoxyglucose (FDG)-positron emission tomography (PET) CT scan showing positive lesions consistent with an anatomic tumor site defined by CT (or MRI), and b) a CT scan (or MRI) with two or more clearly defined lesions / nodes with a long axis greater than 1.5 cm and a short axis greater than 1.0 cm, or one clearly defined lesion / node with a long axis greater than 2.0 cm and a short axis equal to or greater than 1.0 cm.

[0125] In some embodiments, the human subject has an ECOG performance status score of 0 or 2. Information regarding ECOG performance status scores is provided, for example, in Oken et al., Am JClin Oncol 1982 Dec;5(6):649-55.

[0126] In some embodiments, the human subject has acceptable clinical laboratory parameters for: (1) creatine clearance or serum creatine [greater than 45 mL / min (>45 mL / min) using the Cockcroft-Gault formula or less than or equal to 1.5 times the upper limit of normal (Upper limit of normal)]; < 1.5 × ULN) serum creatinine], (2) serum alanine transaminase ( <2.5 × ULN), (3) serum aspartate transaminase ( < 2.5 × ULN), (4) bilirubin (unless due to Gilbert syndrome, < 1.5 × ULN), (5) hemoglobin (unless anemia is due to bone marrow infiltration of CLL, > 9.0 g / dL), (6) absolute neutrophil count [unless neutropenia is due to bone marrow infiltration of CLL; > 1.0×10 9 / L(1000 / μL)] Platelet count [ > 30×10 9 / L) (30,000 / μL)] and coagulation status (PT / INR / aPTT < 1.5 × ULN).

[0127] Human subjects receiving the treatments described herein may be patients who have one or more of the inclusion criteria described in Example 2, or who do not have one or more of the exclusion criteria described in Example 2.

[0128] A subject with Richter's syndrome is classified as having a CD20-positive cancer.Therefore, cancer treatments that a human subject may have previously received include anti-CD20 monoclonal antibodies (e.g., rituximab).RS may be resistant to or recur during such treatment or any other treatment.Therefore, in one embodiment, the subject has been treated with an anti-CD20 monoclonal antibody, such as rituximab or binutuzumab, before treatment with a bispecific antibody.In some embodiments, RS has recurred or been resistant to treatment during previous treatment with an anti-CD20 antibody or a combination of an anti-CD20 monoclonal antibody and a therapeutic agent (e.g., cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, prednisone (R-CHOP)).

[0129] The methods described herein are effective in treating Richter's syndrome, however, treatment may be discontinued if progressive disease occurs or unacceptable toxicity occurs.

[0130] The response of RS patients to the methods described herein can be assessed according to the Lugano criteria (Cheson et al., 2014), as shown in Table 2. [Table 2]

[0131] TIFF2025537529000003.tif242163

[0132] TIFF2025537529000004.tif97164

[0133] 1. A score of 3 in many subjects indicates a favorable prognosis with standard therapy, especially at interim scan time points. However, in clinical trials involving PET where de-escalation is being considered, it may be preferable to consider a score of 3 as an inadequate response (to avoid undertreatment).

[0134] · Primary (target) lesions to be measured: up to six largest major lymph nodes, lymph node masses and extranodal lesions selected as clearly measurable in two diameters.

[0135] - The lymph nodes should preferably be from different regions of the body, including the mediastinal and retroperitoneal regions, if applicable.

[0136] - Non-lymph node disease includes lesions in solid organs (e.g., liver, spleen, kidney, lung), gastrointestinal disorders, skin lesions, or lesions that are visible on palpation.

[0137] · Unmeasured Lesions: Any disease that is not selected as an accurately assessable disease and a primary disease to be measured should be considered an unmeasured lesion.

[0138] - These sites include pleural effusions, ascites, bone lesions, leptomeningeal disease, abdominal masses, and other lesions that cannot be confirmed and tracked by imaging, any site of suspected disease that is difficult to quantitatively track by measurement, accurately assessable disease, and any lymph nodes, lymph node masses, and extranodal sites that do not meet the requirements for measurability but are still considered abnormal or are not selected as primary or measurable.

[0139] In Waldeyer's ring or extranodal sites (e.g., gastrointestinal tract, liver, bone marrow), FDG uptake may be higher than in the mediastinum with a complete metabolic response, but should not be as high as normal physiological uptake in the surrounding area (e.g., with bone marrow activation as a result of chemotherapy or myeloid growth factors).

[0140] 2. PET 5PS: 1 = no uptake above background; 2 = uptake < Mediastinum; 3 = uptake > mediastinum, and < Liver; 4 = uptake (moderately) > liver; 5 = new lesion and / or uptake significantly higher than liver; X = new area of ​​uptake unlikely to be associated with lymphoma. Source: (Cheson et al., 2014, J Clin Oncol 32, 3059-3068).

[0141] Subjects treated according to the methods described herein preferably experience an improvement in at least one symptom of lymphoma.

[0142] In one embodiment, treated subjects demonstrated a complete or partial metabolic response as measured by PET (see PET-CT based responses in Table 2), and Figure 4 shows that 8 of 9 RS patients achieved at least 50% tumor shrinkage from baseline.

[0143] In one embodiment, treated subjects exhibit a complete response (CR), partial response (PR), or stable disease (SD) as defined by the Lugano criteria (Cheson et al., 2014) (see, e.g., Table 2). As shown in Figure 4, eight of nine RS patients achieved at least a 50% reduction in tumor size from baseline.

[0144] In some embodiments, the methods described herein provide at least one therapeutic benefit selected from, for example, increased survival, such as progression-free survival or overall survival, optionally compared to other therapies or placebo. In some embodiments, subjects are treated with the methods described herein until disease progression (PD) or unacceptable toxicity.

[0145] Cytokine release syndrome (CRS) can occur when methods utilizing immune cell and bispecific antibody-based approaches that function through immune effector cell activation, for example, by engaging CD3, are used in human subjects (Lee et al., Biol Blood Marrow Transplant 2019;25:625-38, incorporated herein by reference). Accordingly, in some embodiments, CRS is alleviated in conjunction with the methods described herein. As part of CRS alleviation, a priming dose and / or intermediate dose selection is performed before administering a full dose (e.g., 12-60 mg), as described herein. CRS can be classified according to standard practices (e.g., as reviewed in Lee et al., Biol Blood Marrow Transplant. 2019 Apr;25(4):625-638, incorporated herein by reference). CRS can involve excessive release of cytokines, such as pro-inflammatory cytokines like IL-6, TNF-alpha, or IL-8, which can cause adverse effects like fever, nausea, vomiting, and chills. Therefore, despite the unique antitumor activity of bispecific antibodies such as epcolitamab, their immunological mechanism of action can induce unwanted "side" effects, i.e., unwanted inflammatory responses. Therefore, patients may be further subjected to concurrent treatment, prophylaxis, and / or premedication with, for example, analgesics, antipyretics, and / or anti-inflammatory drugs to alleviate resulting CRS symptoms.

[0146] Thus, in one embodiment, a human subject receives prophylactic treatment against CRS in the methods described herein. In a preferred embodiment, the prophylactic treatment comprises administering a corticosteroid to the subject. In one embodiment, the prophylactic treatment (e.g., a corticosteroid) is administered on the same day as the administration of the bispecific antibody. The prophylactic treatment (e.g., a corticosteroid) can also be administered thereafter. In some embodiments, the prophylactic treatment (e.g., a corticosteroid) is further administered on days 2, 3, and 4 thereafter. Days 2, 3, and 4 of the further administration, such as prophylactic treatment, are understood to be based on the administration of the bispecific antibody administered on day 1. For example, if an antibody is administered on day 15 in a cycle and prophylactic treatment is also administered, the prophylactic treatment corresponding to days 2, 3, and 4 would be days 16, 17, and 18 of the cycle. In some embodiments, the prophylactic treatment is administered on the day the bispecific antibody is administered and on days 2 through 4 thereafter. If the prophylactic treatment is administered on the same day as the bispecific antibody, the prophylactic treatment is preferably administered 30 to 120 minutes prior to administration of the bispecific antibody. An exemplary corticosteroid suitable for use in the methods and uses described herein is prednisolone. In some embodiments, the corticosteroid is prednisolone. In some embodiments, prednisolone is administered at a 100 mg intravenous dose or its equivalent (including oral doses). Exemplary corticosteroid equivalents of prednisolone and equivalent doses that may be used to prevent CRS are listed in Table 6.

[0147] Additionally, in some embodiments, the methods described herein involve a human subject receiving premedication to reduce a reaction to the injection. In one embodiment, the premedication includes administration of an antihistamine. In some embodiments, the premedication includes administration of an antipyretic. In another embodiment, the premedication includes systemic administration of an antihistamine and an antipyretic.

[0148] An exemplary antihistamine suitable for use in premedication includes diphenhydramine. In some embodiments, the antihistamine is diphenhydramine. In one embodiment, diphenhydramine is administered in a 50 mg intravenous or oral dose, or its equivalent. An exemplary antipyretic suitable for use in premedication includes acetaminophen. In some embodiments, the antipyretic is acetaminophen. In one embodiment, acetaminophen is administered in an oral dose of 560-1000 mg, e.g., 650-1000 mg, or its equivalent. In some embodiments, the premedication is administered on the same day as the bispecific antibody. In some embodiments, the premedication is administered on the same day as the bispecific antibody, prior to injection of the bispecific antibody, e.g., 30-120 minutes prior to administration of the bispecific antibody.

[0149] Premedication and / or prophylactic treatment may be administered at least in the early stages of treatment. In some embodiments, premedication and / or prophylactic treatment is administered during the first four administrations of the bispecific antibody. For example, premedication and / or prophylactic treatment may be administered during the first 28-day cycle of bispecific antibody administration as described herein. In some embodiments, premedication is administered in cycle 1. In some embodiments, prophylactic treatment is administered in cycle 1.

[0150] Typically, the risk of a reaction during initial treatment decreases after several doses [e.g., after the first four doses (first cycle)]. Therefore, if a human subject does not experience CRS, prophylactic treatment against CRS can be discontinued. However, if a human subject experiences CRS of grade 1 or higher, CRS prophylaxis can be continued. Similarly, premedication can be continued if desired. CRS grading can be performed as described in Tables 7 and 8.

[0151] In another embodiment, in the methods described herein, if the human subject experiences CRS greater than Grade 1 after the fourth (i.e., final) administration of the bispecific antibody in Cycle 1, prophylaxis is administered in the second 28-day cycle, i.e., Cycle 2. Furthermore, if the human subject experiences CRS greater than Grade 1 upon the final administration of the bispecific antibody in the previous cycle, prophylaxis can be continued during the subsequent cycle. Optional premedication can be administered during Cycle 2. In some embodiments, premedication is administered in Cycle 2. Optional additional premedication can also be administered during the subsequent cycle. In some embodiments, premedication is administered during the subsequent cycle (after Cycle 2).

[0152] In one embodiment, premedication and prophylaxis against CRS is administered, where the premedication includes an antihistamine, e.g., diphenhydramine (e.g., a 50 mg intravenous or oral dose or equivalent), and the prophylaxis includes an antipyretic, e.g., acetaminophen (e.g., a 650-1000 mg oral dose or equivalent), and a corticosteroid, e.g., prednisolone (e.g., a 100 mg intravenous dose or equivalent). In some embodiments, the premedication and prophylaxis is administered 30-120 minutes prior to administration of the bispecific antibody. Additional prophylaxis is administered on days 2, 3, and, optionally, 4 thereafter, including systemic administration of a corticosteroid, e.g., prednisolone (e.g., a 100 mg intravenous dose or equivalent). In some embodiments, the premedication and prophylaxis schedule is preferably administered during the first four doses of the bispecific antibody, e.g., during the first 28-day cycle of bispecific antibody administration described herein. Additionally, if CRS greater than Grade 1 occurs, for example, during the final dose of the previous cycle, the subsequent cycle can include the same dosing schedule, with optional premedication as part of the dosing schedule.

[0153] During treatment of a human subject with RS using the doses and treatment regimens described herein, CRS can be adequately controlled while, at the same time, RS can be effectively controlled and / or treated. As described in the Examples, subjects treated with the methods described herein can experience manageable CRS. In some cases, subjects treated with the methods described herein can develop Grade 1 CRS, as defined by standard practice. In other cases, subjects can develop manageable Grade 2 CRS, as defined by standard practice. Thus, subjects treated with the methods described herein can have manageable Grade 1 or Grade 2 CRS, as defined by standard practice. According to the standard classification of CRS, Grade 1 CRS includes a fever of at least 38°C, the absence of hypotension, and the absence of hypoxia, while Grade 2 CRS includes a fever of at least 38°C, hypotension not requiring vasopressors, and / or hypoxia requiring oxygen supply via low-flow nasal cannula or blow-by. Such manageable CRS can occur in Cycle 1. Human subjects receiving the treatments described herein may also have CRS greater than Grade 2 during the treatment, as defined according to standard practice. Thus, human subjects receiving the treatments described herein may also have CRS of Grade 3 during the treatment, as defined according to standard practice. Such manageable CRS may occur during Cycle 1 and subsequent cycles.

[0154] Subjects treated according to the methods described herein may also experience fever, fatigue, and injection site reactions. They may also experience neurotoxicity, partial seizures, CRS-associated agraphia, or CRS-associated confusional states.

[0155] As noted above, subjects may develop CRS during treatment with the methods described herein despite receiving CRS prophylaxis. CRS grading criteria are described in Tables 7 and 8.

[0156] In one embodiment, if a subject develops grade 1 CRS, the subject is administered an antibiotic. That is, a subject who develops grade 1 CRS is treated with antibiotics if the subject shows infection. In some embodiments, the administration of antibiotics is continued until neutropenia (if present) resolves. In some embodiments, a subject with grade 1 CRS who shows systemic symptoms is treated with an NSAID.

[0157] In one embodiment, subjects who develop Grade 2 CRS are treated with intravenous fluid boluses and / or supplemental oxygen. In some embodiments, subjects who develop Grade 2 CRS are treated with vasopressors. In some embodiments, subjects with Grade 2 CRS who have coexisting conditions are treated with tocilizumab (e.g., a humanized antibody against the IL-6 receptor, commercially available as ACTEMRA®) and / or steroids (e.g., dexamethasone or its equivalent, methylprednisolone). In another embodiment, subjects with concomitant ICANS are administered dexamethasone. In yet another embodiment, if the subject does not show improvement in CRS symptoms within, for example, 6 hours, or if the subject begins to deteriorate after initial improvement, a second dose of tocilizumab is administered along with a dose of corticosteroid. In some embodiments, if the subject is resistant to tocilizumab after three doses, the subject is administered additional cytokine therapy, such as an anti-IL-6 antibody (e.g., siltuximab) or an IL-1R antagonist (e.g., anakinra).

[0158] In one embodiment, subjects who develop Grade 3 CRS are treated with vasopressor (e.g., norepinephrine) support and / or supplemental oxygen. In some embodiments, subjects who develop Grade 3 CRS are treated with tocilizumab, or a combination of tocilizumab and steroids (e.g., dexamethasone or its equivalent of methylprednisolone). In some embodiments, subjects who exhibit concurrent ICANS are administered dexamethasone. In another embodiment, if the subject is resistant to tocilizumab after three doses, the subject is administered additional cytokine therapy, such as an anti-IL-6 antibody (e.g., siltuximab) or an IL-1R antagonist (e.g., anakinra).

[0159] In one embodiment, a subject who develops Grade 4 CRS is treated with vasopressor support and / or supplemental oxygen (e.g., via positive pressure ventilation, e.g., CPAP, BiPAP, intubation, or mechanical ventilation). In some embodiments, if a subject develops Grade 4 CRS, the subject is administered at least two vasopressor medications. In some embodiments, the subject is further administered a steroid. That is, the subject is administered tocilizumab and a steroid. In some embodiments, the steroid is dexamethasone. In some embodiments, the steroid is methylprednisolone. In another embodiment, a subject exhibiting concomitant ICANS is administered dexamethasone. In another embodiment, if the subject is resistant to tocilizumab after three doses, the subject is administered additional cytokine therapy, such as an anti-IL-6 antibody (e.g., siltuximab) or an IL-1R antagonist (e.g., anakinra). In some embodiments, if a subject is resistant to tocilizumab, the administration of tocilizumab is switched to administration of an anti-IL-6 antibody (e.g., siltuximab). In some embodiments, if a subject is resistant to tocilizumab, the administration of tocilizumab is switched to an IL-1R antagonist (e.g., anakinra).

[0160] In some embodiments, a human subject receives prophylactic treatment against tumor lysis syndrome (TLS). That is, the subject is treated with prophylactic treatment against tumor lysis syndrome (TLS). Classification and grading of tumor lysis syndrome can be performed using methods known in the art, for example, the methods described in Howard et al., N Engl J Med 2011;364:1844-54 and Coiffier et al., J Clin Oncol 2008;26:2767-78. In some embodiments, prophylactic treatment against TLS comprises administering one or more uric acid-lowering agents prior to administration of the bispecific antibody. That is, prophylactic treatment against TLS comprises administering one or more uric acid-lowering agents prior to administration of the bispecific antibody. Exemplary uric acid-lowering agents include allopurinol and rasburicase. Thus, in one embodiment, prophylactic treatment against TLS comprises administering allopurinol and / or rasburicase. In some embodiments, prophylactic treatment of TLS involves administering allopurinol and / or rasburicase prior to administration of the bispecific antibody. In one embodiment, allopurinol is administered 72 hours prior to administration of the bispecific antibody. In some embodiments, administration of rasburicase begins after administration of allopurinol and prior to administration of the bispecific antibody. Prior to subsequent administration of the bispecific antibody, a reassessment of the subject's TLS risk classification may be performed. All measurable lymph nodes are less than 5 cm in greatest dimension and are ≥ 25 x 10 9 A subject is considered at low risk for TLS if any measurable lymph node is ≥ 5 cm and < 10 cm in greatest dimension, or if the ALC is < 25 x 10 9 A subject is considered at intermediate risk for TLS if (a) any measurable lymph node has a maximum dimension of 10 cm or greater, or (b) an ALC of 25 × 10 9 A subject is considered at high risk for TLS if their ≥ 100 x 10 / L and any measurable lymph node is ≥ 5 cm and < 10 cm in greatest dimension. 9Subjects with lymphocyte counts above 1 / L are also considered high risk. In some embodiments, if a subject shows signs of TLS, supportive care, such as rasburicase and / or allopurinol, may be used.

[0161] In one embodiment, the bispecific antibody used in the methods described herein is administered subcutaneously and, therefore, is formulated in a pharmaceutical composition so that it is compatible with subcutaneous (sc) administration, i.e., has a formulation and / or concentration that allows for pharmaceutically acceptable subcutaneous administration at the doses described herein. In some embodiments, subcutaneous administration is by injection. For example, formulations of DuoBody-CD3xCD20 that are compatible with subcutaneous formulation and that can be used in the methods described herein have been previously described [see, e.g., WO2019155008, which is incorporated herein by reference]. In some embodiments, the bispecific antibody can be formulated using sodium acetate trihydrate, acetic acid, sodium hydroxide, sorbitol, polysorbate 80, and water for injection, and can have a pH of 5.5 or about 5.5. In some embodiments, the bispecific antibody is provided as a 5 mg / mL or 60 mg / mL concentrate. In another embodiment, the desired dose of bispecific antibody is reconstituted (reconstituted) into a volume of about 1 mL for subcutaneous injection.

[0162] In one embodiment, a suitable pharmaceutical composition for a bispecific antibody can include the bispecific antibody, 20-40 mM acetate, 140-160 mM sorbitol, and a surfactant, such as polysorbate 80, and can have a pH of 5.3-5.6. In some embodiments, a pharmaceutical formulation can include bispecific antibody in the range of 5-100 mg / mL, e.g., 48 or 60 mg / mL, 30 mM acetate, 150 mM sorbitol, 0.04% w / v polysorbate 80, and can have a pH of 5.5. Such formulations can be diluted, for example, with a formulation buffer, to allow for appropriate dosing and subcutaneous administration.

[0163] The volume of the pharmaceutical composition is appropriately selected to enable subcutaneous administration of the antibody. For example, the administered volume is about 0.3 mL to about 3 mL, e.g., in the range of 0.3 mL to 3 mL. The administered volume may be 0.5 mL, 0.8 mL, 1 mL, 1.2 mL, 1.5 mL, 1.7 mL, 2 mL, or 2.5 mL, or about 0.5 mL, about 0.8 mL, about 1 mL, about 1.2 mL, about 1.5 mL, about 1.7 mL, about 2 mL, or about 2.5 mL. Thus, in some embodiments, the administered volume is 0.5 mL or about 0.5 mL. In some embodiments, the administered volume is 0.8 mL or about 0.8 mL. In some embodiments, the administered volume is 1 mL or about 1 mL. In some embodiments, the administered volume is 1.2 mL or about 1.2 mL. In some embodiments, the administered volume is 1.5 mL or about 1.5 mL. In some embodiments, the administered volume is at or about 1.7 mL. In some embodiments, the administered volume is at or about 2 mL. In some embodiments, the administered volume is at or about 2.5 mL.

[0164] The methods described herein (or use of CD3xCD20 antibodies) are intended for the treatment of human patients with CLL. It is understood that the methods described herein can be the initial treatment or part of the initial treatment provided to such patients. However, the patient may have received prior treatment for CLL and / or Richter's syndrome. Previous treatments include, but are not limited to, one or more of chemotherapy, immunotherapy, and targeted therapy, or a combination thereof. Most commonly, standard treatment for RS involves treatment with a combination of cytotoxic chemotherapy and an anti-CD20 monoclonal antibody. The methods described herein can also be used in combination with other treatments.

[0165] In one embodiment, the bispecific antibody used in the methods described herein is (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that includes a variable heavy chain (VH) region and a variable light chain (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences within the amino acid sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences within the amino acid sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region and comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences within the amino acid sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences within the amino acid sequence of SEQ ID NO: 14. Includes.

[0166] CDR1, CDR2, and CDR3 regions can be identified from the variable heavy and variable light chain regions using methods known in the art, and the CDR regions from the variable heavy and variable light chain regions can be annotated according to IMGT (see Lefranc et al., Nucleic Acids Research 1999;27:209-12 and Brochet. Nucleic Acids Res 2008;36:W503-8).

[0167] In some embodiments, the bispecific antibody comprises: (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon), the first binding arm comprising VHCDR1, VHCDR2, and VHCDR3 having the amino acid sequences set forth in SEQ ID NOs: 1, 2, and 3, respectively, and VLCDR1, VLCDR2, and VLCDR3 having the amino acid sequences set forth in SEQ ID NO: 4, SEQ ID NO: GTN, and SEQ ID NO: 5, respectively; and (ii) a second binding arm comprising a second antigen-binding region that binds to human CD20, the second binding arm comprising VHCDR1, VHCDR2, and VHCDR3 having the amino acid sequences set forth in SEQ ID NOs: 8, 9, and 10, respectively, and VLCDR1, VLCDR2, and VLCDR3 having the amino acid sequences set forth in SEQ ID NO: 11, sequence DAS, and SEQ ID NO: 12, respectively; Includes.

[0168] In some embodiments, the bispecific antibody comprises: (i) a first binding arm comprising a VH region comprising the amino acid sequence of SEQ ID NO: 6 and a VL region comprising the amino acid sequence of SEQ ID NO: 7, and comprising a first antigen-binding region that binds to human CD3ε (epsilon); and (ii) a second binding arm comprising a VH region comprising the amino acid sequence of SEQ ID NO: 13 and a VL region comprising the amino acid sequence of SEQ ID NO: 14, and comprising a second antigen-binding region that binds to human CD20; Includes.

[0169] In some embodiments, the bispecific antibody is a full-length antibody. In some embodiments, the bispecific antibody comprises an inactive Fc region. In one embodiment, the bispecific antibody is a full-length antibody and has an inactive Fc region. In some embodiments, the first binding arm to CD3 is derived from a humanized antibody, e.g., a full-length IgG1, λ (lambda) antibody, such as H1L1 described in WO2015001085 (incorporated herein by reference), and / or the second binding arm to CD20 is derived from a human antibody, e.g., a full-length IgG1, κ (kappa) antibody, such as clone 7D8 described in WO2004035607 (incorporated herein by reference). Bispecific antibodies can be produced from two half-molecular antibodies, each of which comprises a first binding arm and a second binding arm, e.g., as described in SEQ ID NOs: 24 and 25 and SEQ ID NOs: 26 and 27, respectively. The half antibodies can be produced in CHO cells and bispecific antibodies can be made, for example, by Fab arm exchange. In one embodiment, the bispecific antibody is a functional variant of DuoBody-CD3xCD20.

[0170] Thus, in some embodiments, the bispecific antibody comprises: (i) a first binding arm comprising a VH region comprising an amino acid sequence at least 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 6, or a VH region comprising the amino acid sequence of SEQ ID NO: 6 with one, two, or three mutations (e.g., amino acid substitutions); and a VL region comprising an amino acid sequence at least 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 7, or a VL region comprising the amino acid sequence of SEQ ID NO: 7 with one, two, or three mutations (e.g., amino acid substitutions), wherein the first binding arm comprises a first antigen-binding region that binds to human CD3ε (epsilon); and (ii) a second binding arm comprising a VH region comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 13, or a VH region comprising the amino acid sequence of SEQ ID NO: 13 with one, two, or three mutations (e.g., amino acid substitutions), and a VL region comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 14, or a VL region comprising the amino acid sequence of SEQ ID NO: 14 with one, two, or three mutations (e.g., amino acid substitutions), and comprising a second antigen-binding region that binds to human CD20. Includes.

[0171] In one embodiment, the bispecific antibody comprises: (i) a first binding arm comprising a heavy chain comprising the amino acid sequence of SEQ ID NO: 24 and a light chain comprising the amino acid sequence of SEQ ID NO: 25, the first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon); and (ii) a second binding arm comprising a VH region comprising the amino acid sequence of SEQ ID NO: 26 and a VL region comprising the amino acid sequence of SEQ ID NO: 27, and comprising a second antigen-binding region that binds to human CD20; Includes.

[0172] In some embodiments, the bispecific antibody comprises: (i) a first binding arm comprising a heavy chain comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 24, or a heavy chain comprising the amino acid sequence of SEQ ID NO: 24 with one, two, or three mutations (e.g., amino acid substitutions); and a light chain comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 25, or a light chain region comprising the amino acid sequence of SEQ ID NO: 25 with one, two, or three mutations (e.g., amino acid substitutions), wherein the first binding arm comprises a first antigen-binding region that binds to human CD3ε (epsilon); and (ii) a second binding arm comprising a heavy chain comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 26, or a heavy chain comprising the amino acid sequence of SEQ ID NO: 26 with one, two, or three mutations (e.g., amino acid substitutions), and a light chain comprising an amino acid sequence at least 85%, 90%, 95%, 98%, or 99% identical to SEQ ID NO: 27, or a light chain region comprising the amino acid sequence of SEQ ID NO: 27 with one, two, or three mutations (e.g., amino acid substitutions), and comprising a second antigen-binding region that binds to human CD20. Includes.

[0173] Various constant regions or variants thereof can be used in bispecific antibodies. In one embodiment, the antibody comprises an IgG constant region, e.g., a human IgG1 constant region, e.g., the human IgG1 constant region set forth in SEQ ID NO: 15, or any other suitable IgG1 allotype. In some embodiments, the bispecific antibody is a full-length antibody having a human IgG1 constant region. In some embodiments, the first binding arm of the bispecific antibody is derived from a humanized antibody, preferably a full-length IgG1, λ (lambda) antibody. In one embodiment, the first binding arm of the bispecific antibody is derived from a humanized antibody, e.g., a full-length IgG1, λ (lambda) antibody, and thus comprises a λ light chain constant region. In some embodiments, the first binding arm comprises the λ light chain constant region set forth in SEQ ID NO: 22. In some embodiments, the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1, κ (kappa) antibody. In some embodiments, the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1,κ (kappa) antibody, and thus may comprise a κ light chain constant region. In some embodiments, the second binding arm comprises the κ light chain constant region set forth in SEQ ID NO: 23. In a preferred embodiment, the first binding arm comprises the λ light chain constant region set forth in SEQ ID NO: 22, and the second binding arm comprises the κ light chain constant region set forth in SEQ ID NO: 23.

[0174] It is understood that the constant region portions of the bispecific antibody may contain modifications that allow for efficient formation / production of the bispecific antibody and / or provide an inactive Fc region. Such modifications are well known in the art.

[0175] Various forms of bispecific antibodies are known in the art (reviewed in Kontermann, Drug Discov Today 2015;20:838-47; MAbs, 2012;4:182-97). Thus, the bispecific antibodies used in the methods and uses described herein are not limited to any particular bispecific antibody form or method of production. For example, bispecific antibodies can include, but are not limited to, bispecific antibodies containing complementary CH3 domains that force heterodimer formation, knobs-into-holes molecules (Genentech, WO9850431), cross MAbs (Roche, WO2011117329), or electrostatically matched molecules (Amgen, EP1870459 and WO2009089004; Chugai, US201000155133; Oncomed, WO2010129304).

[0176] Preferably, the bispecific antibody comprises an Fc region comprising a first heavy chain having a first Fc sequence comprising a first CH3 region and a second heavy chain having a second Fc sequence comprising a second CH3 region, wherein the sequences of the first CH3 region and the second CH3 region are different and the heterodimeric interaction between the first CH3 region and the second CH3 region is stronger than the homodimeric interaction between the first CH3 region and the second CH3 region, respectively. Further details regarding these interactions and how they may be achieved are described, for example, in WO2011131746 and WO2013060867 (Genmab), which are incorporated herein by reference. In one embodiment, the bispecific antibody comprises, in the first heavy chain (i), an amino acid L at a position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15, and in the second heavy chain, an amino acid R at a position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15, or vice versa.

[0177] Bispecific antibodies may contain modifications to the Fc region to render the Fc region inactive or inactive. Thus, in the bispecific antibodies disclosed herein, one or both heavy chains can be modified such that the antibody induces Fc-mediated effector function to a lesser extent than a bispecific antibody lacking the modification. Fc-mediated effector function can be measured by induction of Fc-mediated CD69 expression on T cells (i.e., CD69 expression as a result of CD3 antibody-mediated Fcγ receptor-dependent CD3 cross-linking), binding to Fcγ receptors, binding to C1q, or Fc-mediated cross-linking of FcγRs. In particular, the heavy chain constant region sequence can be modified to reduce Fc-mediated CD69 expression by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 99%, or 100% compared to a wild-type (unmodified) antibody, where the Fc-mediated CD69 expression is measured in a PBMC-based functional assay, for example, as described in Example 3 of WO2015001085. Modification of the heavy and light chain constant region sequences can also result in reduced C1q binding to the antibody. Compared to an unmodified antibody, the reduction can be at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, or 100%, and C1q binding can be measured, for example, by ELISA. Furthermore, the Fc region can be modified such that the antibody reduces Fc-mediated T cell proliferation by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 99%, or 100% compared to an unmodified antibody, where the T cell proliferation is measured in a PBMC-based functional assay. For example, examples of amino acid positions that can be modified in an IgG1 isotype antibody include positions L234 and L235. Thus, in one embodiment, the bispecific antibody can comprise a first heavy chain and a second heavy chain, where the amino acid residues at positions corresponding to positions L234 and L235 in a human IgG1 heavy chain according to EU numbering are F and E, respectively, in both the first and second heavy chains.Furthermore, the D265A amino acid substitution can reduce binding to all Fcγ receptors and prevent ADCC (Shields et al., JBC 2001;276:6591-604). Thus, a bispecific antibody can comprise a first heavy chain and a second heavy chain, wherein the amino acid residue at the position corresponding to position D265 in a human IgG1 heavy chain according to Eu numbering is A in both the first and second heavy chains.

[0178] In one embodiment, the amino acids at positions in the first and second heavy chains of the bispecific antibody that correspond to positions L234, L235, and D265 in a human IgG1 heavy chain are F, E, and A, respectively. An antibody having these amino acids at these positions is an example of an antibody having an inactive or non-activated Fc region.

[0179] In some embodiments, the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in both the first and second heavy chains, the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively. In some embodiments, the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in the first heavy chain, the amino acid at position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain, the amino acid at position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa. In a preferred embodiment, the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein (i) in both the first and second heavy chains, the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively; and (ii) in the first heavy chain, the amino acid at position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain, the amino acid at position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

[0180] With respect to the bispecific antibodies described herein, antibodies having the combination of the three amino acid substitutions L234F, L235E and D265A, plus the K409R or F405L mutations described above, may be referred to with the suffix "FEAR" or "FEAL", respectively.

[0181] The amino acid sequence of a wild-type IgG1 heavy chain constant region may be identified herein as SEQ ID NO: 15. Consistent with the embodiments disclosed above, a bispecific antibody may comprise an IgG1 heavy chain constant region containing an F405L substitution, may have the amino acid sequence set forth in SEQ ID NO: 17 and / or an IgG1 heavy chain constant region containing a K409R substitution, may have the amino acid sequence set forth in SEQ ID NO: 18, and may have additional substitutions that render the Fc region inactive or inactivated. Thus, in one embodiment, a bispecific antibody comprises a combination of IgG1 heavy chain constant regions, wherein the amino acid sequence of one IgG1 heavy chain constant region contains L234F, L235E, D265A, and F405L substitutions (e.g., as set forth in SEQ ID NO: 19), and the amino acid sequence of the other IgG1 heavy chain constant region contains L234F, L235E, D265A, and K409R substitutions (e.g., as set forth in SEQ ID NO: 20). Thus, in some embodiments, the bispecific antibody comprises a heavy chain constant region comprising the amino acid sequence of SEQ ID NOs: 19 and 20.

[0182] In preferred embodiments, the bispecific antibody used in the methods and uses described herein comprises a first binding arm comprising the heavy and light chains set forth in SEQ ID NOs: 24 and 25, respectively, and a second binding arm comprising the heavy and light chains set forth in SEQ ID NOs: 26 and 27, respectively. Such antibodies may also be referred to herein as DuoBody-CD3xCD20. Variants of such antibodies are also contemplated for use in the methods and uses described herein. In some embodiments, the bispecific antibody comprises heavy and light chains consisting of the amino acid sequences set forth in SEQ ID NOs: 24 and 25, respectively, and heavy and light chains consisting of the amino acid sequences set forth in SEQ ID NOs: 26 and 27, respectively. In some embodiments, the bispecific antibody is epcolitamab (CAS 2134641-34-0) or a biosimilar thereof.

[0183] kit Also provided herein are kits comprising pharmaceutical compositions containing a therapeutically effective amount of a bispecific antibody that binds to CD3 and CD20 according to the present invention (e.g., DuoBody-CD3xCD20 or epcolitamab) and a pharmaceutically acceptable carrier suitable for use in the methods described herein. The kits may optionally include instructions, including, for example, an administration schedule, that allow a practitioner (e.g., a physician, nurse, or patient) to administer the composition included in the kit to a CLL patient. The kit may also include a syringe.

[0184] Optionally, the kit may contain multiple packages of single-dose (e.g., 12-60 mg, e.g., 12 mg, 24 mg, 36 mg, 48 mg, or 60 mg doses) pharmaceutical compositions, each containing an effective amount of a bispecific antibody for a single administration according to the methods described herein. Instruments or devices necessary for administering the pharmaceutical compositions may also be included in the kit. For example, the kit may include one or more pre-filled syringes containing a quantity of the bispecific antibody.

[0185] Additional Embodiments 1. (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that comprises a variable heavy (VH) region and a variable light (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region and comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 14. 1. A method for treating Richter's syndrome (RS) in a human subject, comprising administering to the subject a bispecific antibody comprising:

[0186] 2. The method of embodiment 1, wherein the bispecific antibody is administered at a dose of 24 mg.

[0187] 3. The method of embodiment 1, wherein the bispecific antibody is administered at a dose of 48 mg.

[0188] 4. The method of any one of embodiments 1 to 3, wherein the bispecific antibody is administered once a week (weekly administration).

[0189] 5. The method of embodiment 4, wherein the weekly administration is in 2.5 28-day cycles.

[0190] 6. The method of embodiment 4 or 5, wherein the bispecific antibody is administered weekly, followed by once every two weeks (biweekly administration).

[0191] 7. The method of embodiment 6, wherein the biweekly administration occurs in six 28-day cycles.

[0192] 8. The method of embodiment 6 or 7, wherein the bispecific antibody is administered every other week, followed by once every four weeks.

[0193] 9. The method of any one of embodiments 4 to 8, wherein a priming dose of the bispecific antibody is administered in cycle 1 of a 28 day cycle prior to administration of the first weekly dose of 12 to 60 mg.

[0194] 10. The method of embodiment 9, wherein a priming dose is administered two weeks prior to administering the first weekly dose of 12 to 60 mg.

[0195] 11. The method of embodiment 9 or 10, wherein the priming dose ranges from 0.05 to 0.35 mg.

[0196] 12. The method of any one of embodiments 9-11, wherein the priming dose is at or about 0.16 mg.

[0197] 13. The method of any one of embodiments 9-12, wherein an intermediate dose of the bispecific antibody is administered after the priming dose and before the first weekly dose of 12-60 mg is administered.

[0198] 14. The method of embodiment 13, wherein a priming dose is administered on day 1 and an intermediate dose is administered on day 8 prior to administration of the first weekly dose of 12-60 mg on days 15 and 22 of cycle 1.

[0199] 15. The method of embodiment 13 or 14, wherein the intermediate dose is in the range of 0.6 to 1.2 mg.

[0200] 16. The method of any one of embodiments 13-15, wherein said intermediate dose is at or about 0.8 mg.

[0201] 17. The bispecific antibody is administered in a 28-day cycle, wherein: a) In cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) The method of any one of embodiments 13-16, wherein in cycle 10 and subsequent cycles, a full dose of 12-60 mg is administered on day 1.

[0202] 18. The method of embodiment 17, wherein the full dose is at or about 24 mg.

[0203] 19. The method of embodiment 17, wherein the full dose is at or about 48 mg.

[0204] 20. The method of any one of embodiments 1 to 19, wherein the bispecific antibody is administered subcutaneously.

[0205] 21. The method of any one of embodiments 1-20, wherein the subject has a clinical history of CLL / SLL with transformation to an aggressive lymphoma, for example of the DLBCL subtype.

[0206] 22. The method of any one of embodiments 1-21, wherein Richter's syndrome is of the DLBCL subtype.

[0207] 23. The method of any one of embodiments 1-22, wherein the subject has received one or more, e.g., at least two, prior lines of treatment for chronic lymphocytic leukemia (CLL) and / or small lymphocytic lymphoma (SLL).

[0208] 24. The method of any one of the previous embodiments, wherein the previous line of treatment for CLL and / or SLL comprises chemoimmunotherapy.

[0209] 25. The method of any one of the preceding embodiments, wherein the previous line of treatment for CLL and / or SLL includes therapy using a targeted agent, such as a BCL2 inhibitor or a BTK inhibitor.

[0210] 26. The method of any one of the preceding embodiments, wherein the previous line of treatment for CLL and / or SLL included CAR T cell therapy.

[0211] 27. The subject has had previous treatment for Richter's syndrome, e.g., i) rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); ii) rituximab in combination with dexamethasone, cytarabine, and cisplatin (R-DHAP), and iii) Venetoclax in combination with rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH) The method of any one of embodiments 1 to 23, wherein the patient has received a previous treatment selected from the group consisting of:

[0212] 28. The method of any one of embodiments 1-27, wherein the subject achieves a complete or partial metabolic response.

[0213] 29. The method of any one of embodiments 1-27, wherein the subject achieves a complete response (complete response), a partial response (partial response), or stable disease.

[0214] 30. The method of any one of embodiments 1-26, wherein the subject receives epcolitamab as a first-line treatment for Richter's syndrome.

[0215] 31. The method of any one of embodiments 1-30, wherein the subject achieves a complete or partial metabolic response.

[0216] 32. The method of any one of embodiments 1-30, wherein the subject achieves a complete response, a partial response, or stable disease.

[0217] 33. The method of any one of embodiments 1-26 and 30-32, wherein the method is a first-line treatment for Richter's syndrome.

[0218] 34. The method of any one of embodiments 21-29, wherein the subject has resistant and / or recurrent Richter's syndrome after undergoing said previous treatment.

[0219] 35. The method of any one of embodiments 1-34, wherein the subject is treated with a preventative treatment against cytokine release syndrome (CRS).

[0220] 36. The method of embodiment 35, wherein the preventative treatment comprises administering a corticosteroid to the subject.

[0221] 37. The method of embodiment 35 or 36, wherein the corticosteroid is administered on the same day as the bispecific antibody.

[0222] 38. The method of embodiment 37, further comprising administering a corticosteroid on days 2, 3, and 4 after administration of the bispecific antibody.

[0223] 39. The method of any one of embodiments 36-38, wherein the corticosteroid is prednisolone.

[0224] 40. The method of embodiment 39, wherein prednisolone is administered at an intravenous dose of 100 mg or its equivalent (including oral doses).

[0225] 41. The method of any one of embodiments 1-40, wherein the subject is premedicated to reduce a reaction to the injection.

[0226] 42. The method of embodiment 41, wherein the premedication comprises an antihistamine.

[0227] 43. The method of embodiment 42, wherein the antihistamine is diphenhydramine.

[0228] 44. The method of embodiment 43, wherein diphenhydramine is administered in an intravenous or oral dose of 50 mg, or an equivalent dose.

[0229] 45. The method of any one of embodiments 41-44, wherein the premedication comprises an antipyretic.

[0230] 46. ​​The method of embodiment 45, wherein the antipyretic is acetaminophen.

[0231] 47. The method of embodiment 46, wherein acetaminophen is administered at an oral dose of 560 to 1000 mg, or its equivalent.

[0232] 48. The method of any one of embodiments 41 to 47, wherein the premedication is administered on the same day as the bispecific antibody.

[0233] 49. The method of any one of embodiments 35 to 48, wherein prophylaxis is administered in cycle 1.

[0234] 50. The method of any one of embodiments 41 to 49, wherein premedication is administered in cycle 1.

[0235] 51. The method of embodiment 49 or 50, wherein if the subject experiences CRS greater than grade 1 after the final administration of the bispecific antibody in cycle 1, then prophylaxis is administered in cycle 2.

[0236] 52. The method of embodiment 51, wherein prophylaxis is continued in subsequent cycles if, upon final administration of the bispecific antibody in the previous cycle, the subject experiences CRS greater than Grade 1.

[0237] 53. The method of any one of embodiments 41-52, wherein premedication is administered in cycle 2.

[0238] 54. The method of embodiment 53, wherein premedication is administered in subsequent cycles.

[0239] 55. The method of any one of embodiments 1-54, wherein an antibiotic is administered to the subject if the subject develops grade 1 CRS.

[0240] 56. The method of any one of embodiments 1-54, wherein if the subject develops Grade 2 or Grade 3 CRS, a vasopressor is administered to the subject.

[0241] 57. The method of any one of embodiments 1-54, wherein if the subject develops grade 4 CRS, then at least two vasopressor agents are administered to the subject.

[0242] 58. The method of any one of embodiments 1-57, wherein tocilizumab is administered to the subject if the subject develops Grade 2, Grade 3, or Grade 4 CRS.

[0243] 59. The method of embodiment 58, further comprising administering a steroid to the subject.

[0244] 60. The method of embodiment 59, wherein the steroid is dexamethasone.

[0245] 61. The method of embodiment 59, wherein the steroid is methylprednisolone.

[0246] 62. The method of any one of embodiments 58-61, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an anti-IL-6 antibody (e.g., siltuximab).

[0247] 63. The method of any one of embodiments 58-61, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an IL-1R antagonist (e.g., anakinra).

[0248] 64. The method of any one of embodiments 1-63, wherein the subject is treated with prophylactic treatment against tumor lysis syndrome (TLS).

[0249] 65. The method of embodiment 64, wherein the prophylactic treatment against TLS comprises administering one or more uric acid-lowering agents prior to administration of the bispecific antibody.

[0250] 66. The method of embodiment 65, wherein the one or more uric acid-lowering agents comprise rasburicase and / or allopurinol.

[0251] 67. The method of any one of embodiments 1-66, wherein the subject achieves a complete response, a partial response, or stable disease.

[0252] 68. (i) the first antigen-binding region comprises VHCDR1, VHCDR2, and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 1, 2, and 3, respectively, and VLCDR1, VLCDR2, and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 4, SEQ ID NO: GTN, and SEQ ID NO: 5, respectively; and (ii) A method described in any one of embodiments 1 to 67, wherein the second antigen-binding region comprises VHCDR1, VHCDR2 and VHCDR3 having the amino acid sequences set forth in SEQ ID NOs: 8, 9 and 10, respectively, and VLCDR1, VLCDR2 and VLCDR3 having the amino acid sequences set forth in SEQ ID NO: 11, sequence DAS and SEQ ID NO: 12, respectively.

[0253] 69. (i) the first antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO: 6 and a VL region comprising the amino acid sequence of SEQ ID NO: 7; and (ii) The method according to any one of embodiments 1 to 68, wherein the second antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO: 13 and a VL region comprising the amino acid sequence of SEQ ID NO: 14.

[0254] 70. The method of any one of embodiments 1 to 68, wherein the first binding arm of the bispecific antibody is derived from a humanized antibody, preferably a full-length IgG1, λ (lambda) antibody.

[0255] 71. The method of embodiment 70, wherein the first binding arm of the bispecific antibody comprises a lambda light chain constant region comprising the amino acid sequence set forth in SEQ ID NO: 22.

[0256] 72. The method of any one of embodiments 1 to 71, wherein the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1, κ (kappa) antibody.

[0257] 73. The method of embodiment 72, wherein the second binding arm comprises a kappa light chain constant region comprising the amino acid sequence set forth in SEQ ID NO: 23.

[0258] 74. The method of any one of embodiments 1-73, wherein the bispecific antibody is a full-length antibody having a human IgG1 constant region.

[0259] 75. The method of any one of embodiments 1-74, wherein the bispecific antibody comprises an inactive Fc region.

[0260] 76. The method of any one of embodiments 1 to 75, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to positions L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively.

[0261] 77. The method of any one of embodiments 1 to 76, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in the first heavy chain the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

[0262] 78. The bispecific antibody comprises a first heavy chain and a second heavy chain, wherein: (i) in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively; and (ii) The method of any one of embodiments 1 to 77, wherein, in the first heavy chain, the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and, in the second heavy chain, the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

[0263] 79. The method of embodiment 78, wherein the bispecific antibody comprises a heavy chain constant region comprising the amino acid sequences of SEQ ID NOs: 19 and 20.

[0264] 80. The method of any one of embodiments 1 to 79, wherein the bispecific antibody comprises heavy and light chains comprising the amino acid sequences set forth in SEQ ID NOs: 24 and 25, respectively, and heavy and light chains comprising the amino acid sequences set forth in SEQ ID NOs: 26 and 27, respectively.

[0265] 81. The method of any one of embodiments 1 to 80, wherein the bispecific antibody comprises heavy and light chains consisting of the amino acid sequences of SEQ ID NOs: 24 and 25, respectively, and heavy and light chains consisting of the amino acid sequences of SEQ ID NOs: 26 and 27, respectively.

[0266] 82. The method of any one of embodiments 1-81, wherein the bispecific antibody is epcolitamab or a biosimilar thereof.

[0267] 1a. For use in treating Richter's syndrome (RS) in a human subject, (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that comprises a variable heavy (VH) region and a variable light (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region and comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 14. wherein the treatment comprises administering the bispecific antibody to a subject in a 28 day cycle at a dose ranging from 12 to 60 mg.

[0268] 2a. The bispecific antibody for use according to embodiment 1a, wherein the bispecific antibody is administered in a dose of 24 mg.

[0269] 3a. The bispecific antibody for use according to embodiment 1a, wherein the bispecific antibody is administered in a dose of 48 mg.

[0270] 4a. The bispecific antibody for use according to any one of embodiments 1 to 3a, wherein the bispecific antibody is administered once a week (weekly administration).

[0271] 5a. The bispecific antibody for use according to embodiment 4a, wherein the administration is weekly in 2.5 28-day cycles.

[0272] 6a. The bispecific antibody for use according to embodiment 4 or 5a, wherein the bispecific antibody is administered weekly followed by once every two weeks (biweekly administration).

[0273] 7a. The bispecific antibody for use according to embodiment 6a, wherein the administration is every other week for six 28-day cycles.

[0274] 8a. The bispecific antibody for use according to embodiment 6a or 7a, wherein the bispecific antibody is administered every other week, followed by once every four weeks.

[0275] 9a. The bispecific antibody for use according to any one of embodiments 4 to 8a, wherein a priming dose of the bispecific antibody is administered in cycle 1 of a 28 day cycle prior to administration of the first weekly dose of 12 to 60 mg.

[0276] 10a. The bispecific antibody for use according to embodiment 9a, wherein a priming dose is administered two weeks before the first weekly dose of 12 to 60 mg.

[0277] 11a. The bispecific antibody for use according to embodiment 9a or 10a, wherein the priming dose is in the range of 0.05 to 0.35 mg.

[0278] 12a. The bispecific antibody for use according to any one of embodiments 9 to 11a, wherein said priming dose is at or about 0.16 mg.

[0279] 13a. The bispecific antibody for use according to any one of embodiments 9 to 12a, wherein an intermediate dose of the bispecific antibody is administered after the priming dose and before the first weekly dose of 12 to 60 mg is administered.

[0280] 14a. The bispecific antibody for use according to embodiment 13a, wherein a priming dose is administered on day 1 and an intermediate dose is administered on day 8 prior to administration of the first weekly doses of 12-60 mg on days 15 and 22 of cycle 1.

[0281] 15a. The bispecific antibody for use according to embodiment 13a or 14a, wherein the intermediate dose is in the range of 0.6 to 1.2 mg.

[0282] 16a. The bispecific antibody for use according to any one of embodiments 13 to 15a, wherein said intermediate dose is at or about 0.8 mg.

[0283] 17a. The bispecific antibody is administered in a 28-day cycle, wherein: a) In cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; b) Cycles 2-3, full doses of 12-60 mg administered on days 1, 8, 15, and 22; c) in cycles 4 through 9, a full dose of 12 to 60 mg is administered on days 1 and 15; and d) The bispecific antibody for use according to any one of embodiments 13 to 16a, wherein in cycle 10 and subsequent cycles, a full dose of 12 to 60 mg is administered on day 1.

[0284] 18a. The bispecific antibody for use according to embodiment 17a, wherein the full dose is at or about 24 mg.

[0285] 19a. The bispecific antibody for use according to embodiment 17a, wherein the full dose is at or about 48 mg.

[0286] 20a. The bispecific antibody for use according to any one of embodiments 1 to 19a, wherein the bispecific antibody is administered subcutaneously.

[0287] 21a. The bispecific antibody for use according to any one of embodiments 1 to 20a, wherein the subject has a clinical history of CLL / SLL with transformation to an aggressive lymphoma, for example of the DLBCL subtype.

[0288] 22a. The bispecific antibody for use according to any one of embodiments 1 to 21a, wherein Richter's syndrome is of the DLBCL subtype.

[0289] 23a. The bispecific antibody for use according to any one of embodiments 1 to 22a, wherein the subject has received one or more, such as at least two, previous lines of treatment for chronic lymphocytic leukemia (CLL) and / or small lymphocytic lymphoma (SLL).

[0290] 24a. The bispecific antibody for use according to any one of the previous embodiments, wherein the previous line of treatment for CLL and / or SLL comprises chemoimmunotherapy.

[0291] 25a. The bispecific antibody for use according to any one of the previous embodiments, wherein the previous line of treatment for CLL and / or SLL comprises therapy using a targeted agent, such as a BCL2 inhibitor or a BTK inhibitor.

[0292] 26a. The bispecific antibody for use according to any one of the previous embodiments, wherein the previous line of treatment for CLL and / or SLL comprises CAR T cell therapy.

[0293] 27a. The subject has not received any prior treatment for Richter's syndrome, e.g., i) rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); ii) rituximab in combination with dexamethasone, cytarabine, and cisplatin (R-DHAP), and iii) Venetoclax in combination with rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH) 23. The bispecific antibody for use according to any one of embodiments 1 to 23a, wherein the patient has received a previous treatment selected from:

[0294] 28a. The bispecific antibody for use according to any one of embodiments 1 to 27a, wherein the subject achieves a complete or partial metabolic response.

[0295] 29a. The bispecific antibody for use according to any one of embodiments 1 to 27a, wherein the subject achieves a complete response, a partial response or stable disease.

[0296] 30a. The bispecific antibody for use according to any one of embodiments 1 to 26a, wherein the subject is receiving epcolitamab as first line treatment for Richter's syndrome.

[0297] 31a. The bispecific antibody for use according to any one of embodiments 1 to 30a, wherein the subject achieves a complete or partial metabolic response.

[0298] 32a. The bispecific antibody for use according to any one of embodiments 1 to 30a, wherein the subject achieves a complete response, a partial response or stable disease.

[0299] 33a. The bispecific antibody for use according to any one of embodiments 1 to 26a and 30 to 32a, wherein the method is first line treatment for Richter's syndrome.

[0300] 34a. The bispecific antibody for use according to any one of embodiments 21 to 29a, wherein the subject has resistant and / or relapsing Richter's syndrome after undergoing said previous treatment.

[0301] 35a. The bispecific antibody for use according to any one of embodiments 1 to 34a, wherein the subject is treated with a prophylactic treatment against cytokine release syndrome (CRS).

[0302] 36a. The bispecific antibody for use according to embodiment 35a, wherein the prophylactic treatment comprises administering a corticosteroid to the subject.

[0303] 37a. The bispecific antibody for use according to embodiment 35a or 36a, wherein the corticosteroid is administered on the same day as the bispecific antibody.

[0304] 38a. The bispecific antibody for use according to embodiment 37a, further comprising administering a corticosteroid on days 2, 3 and 4 after administration of the bispecific antibody.

[0305] 39a. The bispecific antibody for use according to any one of embodiments 36 to 38a, wherein the corticosteroid is prednisolone.

[0306] 40a. The bispecific antibody for use according to embodiment 39a, wherein prednisolone is administered in an intravenous dose of 100 mg or its equivalent (including oral doses).

[0307] 41a. The bispecific antibody for use according to any one of embodiments 1 to 40a, wherein the subject is premedicated to reduce any reaction to injection.

[0308] 42a. The bispecific antibody for use according to embodiment 41a, wherein the premedication comprises an antihistamine.

[0309] 43a. The bispecific antibody for use according to embodiment 42a, wherein the antihistamine is diphenhydramine.

[0310] 44a. The bispecific antibody for use according to embodiment 43a, wherein diphenhydramine is administered in an intravenous or oral dose of 50 mg, or an equivalent dose.

[0311] 45a. The bispecific antibody for use according to any one of embodiments 41 to 44a, wherein the premedication comprises an antipyretic.

[0312] 46a. The bispecific antibody for use according to embodiment 45a, wherein the antipyretic is acetaminophen.

[0313] 47a. The bispecific antibody for use according to embodiment 46a, wherein acetaminophen is administered at an oral dose of 560 to 1000 mg or an equivalent dose.

[0314] 48a. The bispecific antibody for use according to any one of embodiments 41 to 47a, wherein the premedication is administered on the same day as the bispecific antibody.

[0315] 49a. The bispecific antibody for use according to any one of embodiments 35 to 48a, wherein prophylaxis is administered in cycle 1.

[0316] 50a. The bispecific antibody for use according to any one of embodiments 41 to 49a, wherein premedication is administered in cycle 1.

[0317] 51a. The bispecific antibody for use according to embodiment 49a or 50a, wherein if the subject experiences CRS greater than grade 1 after the last administration of the bispecific antibody in cycle 1, then prophylaxis is administered in cycle 2.

[0318] 52a. The bispecific antibody for use according to embodiment 51a, wherein if upon the final administration of the bispecific antibody in the previous cycle the subject experiences CRS greater than grade 1, then prophylaxis is continued in the subsequent cycle.

[0319] 53a. The bispecific antibody for use according to any one of embodiments 41 to 52a, wherein premedication is administered in cycle 2.

[0320] 54a. The bispecific antibody for use according to embodiment 53a, wherein premedication is administered in subsequent cycles.

[0321] 55a. The bispecific antibody for use according to any one of embodiments 1 to 54a, wherein an antibiotic is administered to the subject if the subject develops Grade 1 CRS.

[0322] 56a. The bispecific antibody for use according to any one of embodiments 1 to 54a, wherein if the subject develops grade 2 or grade 3 CRS, a vasopressor is administered to the subject.

[0323] 57a. The bispecific antibody for use according to any one of embodiments 1 to 54a, wherein at least two vasopressor agents are administered to the subject if the subject develops grade 4 CRS.

[0324] 58a. The bispecific antibody for use according to any one of embodiments 1 to 57a, wherein tocilizumab is administered to the subject if the subject develops Grade 2, Grade 3 or Grade 4 CRS.

[0325] 59a. The bispecific antibody for use according to embodiment 58a, wherein a steroid is further administered to the subject.

[0326] 60a. The bispecific antibody for use according to embodiment 59a, wherein the steroid is dexamethasone.

[0327] 61a. The bispecific antibody for use according to embodiment 59a, wherein the steroid is methylprednisolone.

[0328] 62a. The bispecific antibody for use according to any one of embodiments 58 to 61a, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an anti-IL-6 antibody (e.g., siltuximab).

[0329] 63a. The bispecific antibody for use according to any one of embodiments 58 to 61a, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an IL-1R antagonist (e.g., anakinra).

[0330] 64a. The bispecific antibody according to any one of embodiments 1 to 63a for use in treating a subject in a prophylactic treatment against tumor lysis syndrome (TLS).

[0331] 65a. The bispecific antibody for use according to embodiment 64a, wherein the prophylactic treatment against TLS comprises administering one or more uric acid-lowering agents prior to administration of the bispecific antibody.

[0332] 66a. The bispecific antibody for use according to embodiment 65a, wherein the one or more uric acid-lowering agents comprise rasburicase and / or allopurinol.

[0333] 67a. The bispecific antibody for use according to any one of embodiments 1 to 66a, wherein the subject achieves a complete response, a partial response, or stable disease.

[0334] 68a.(i) a first antigen-binding region comprising VHCDR1, VHCDR2 and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 1, 2 and 3, respectively, and VLCDR1, VLCDR2 and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 4, SEQ ID NO: GTN and SEQ ID NO: 5, respectively; and (ii) The bispecific antibody for use according to any one of embodiments 1 to 67a, wherein the second antigen-binding region comprises VHCDR1, VHCDR2 and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 8, 9 and 10, respectively, and VLCDR1, VLCDR2 and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 11, sequence DAS and SEQ ID NO: 12, respectively.

[0335] 69a.(i) the first antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO:6 and a VL region comprising the amino acid sequence of SEQ ID NO:7; and (ii) The bispecific antibody for use according to any one of embodiments 1 to 68a, wherein the second antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO: 13 and a VL region comprising the amino acid sequence of SEQ ID NO: 14.

[0336] 70a. The bispecific antibody for use according to any one of embodiments 1 to 68a, wherein the first binding arm of the bispecific antibody is derived from a humanized antibody, preferably a full-length IgG1, λ (lambda) antibody.

[0337] 71a. The bispecific antibody for use according to embodiment 70a, wherein the first binding arm of the bispecific antibody comprises a lambda light chain constant region comprising the amino acid sequence set forth in SEQ ID NO: 22.

[0338] 72a. The bispecific antibody for use according to any one of embodiments 1 to 71a, wherein the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1, κ (kappa) antibody.

[0339] 73a. The bispecific antibody for use according to embodiment 72a, wherein the second binding arm comprises a kappa light chain constant region comprising the amino acid sequence set forth in SEQ ID NO: 23.

[0340] 74a. The bispecific antibody for use according to any one of embodiments 1 to 73a, wherein the bispecific antibody is a full-length antibody having a human IgG1 constant region.

[0341] 75a. The bispecific antibody for use according to any one of embodiments 1 to 74a, wherein the bispecific antibody comprises an inactive Fc region.

[0342] 76a. The bispecific antibody for use according to any one of embodiments 1 to 75a, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to L234, L235 and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E and A, respectively.

[0343] 77a. The bispecific antibody for use according to any one of embodiments 1 to 76a, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in the first heavy chain the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

[0344] 78a. The bispecific antibody comprises a first heavy chain and a second heavy chain, wherein: (i) in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively; and (ii) The bispecific antibody for use according to any one of embodiments 1 to 77a, wherein in the first heavy chain the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

[0345] 79a. The bispecific antibody for use according to embodiment 78a, wherein the bispecific antibody comprises a heavy chain constant region comprising the amino acid sequences of SEQ ID NOs: 19 and 20.

[0346] 80a. The bispecific antibody for use according to any one of embodiments 1 to 79a, wherein the bispecific antibody comprises a heavy chain and a light chain comprising the amino acid sequences set forth in SEQ ID NOs: 24 and 25, respectively, and a heavy chain and a light chain comprising the amino acid sequences set forth in SEQ ID NOs: 26 and 27, respectively.

[0347] 81a. A bispecific antibody for use according to any one of embodiments 1 to 80a, wherein the bispecific antibody comprises a heavy chain and a light chain consisting of the amino acid sequences of SEQ ID NOs: 24 and 25, respectively, and a heavy chain and a light chain consisting of the amino acid sequences of SEQ ID NOs: 26 and 27, respectively.

[0348] 82a. The bispecific antibody for use according to any one of embodiments 1 to 81a, wherein the bispecific antibody is epcolitamab or a biosimilar thereof.

[0349] The present disclosure is further illustrated by the following examples, which should not be construed as further limiting. The contents of all figures and all references, Genbank sequences, patents and published patent applications cited throughout this application are expressly incorporated herein by reference.

[0350] Example DuoBody-CD3×CD20 DuoBody-CD3xCD20 is a bsAb that recognizes the T cell antigen CD3 and the B cell antigen CD20. DuoBody-CD3xCD20 induces potent T cell-mediated killing of CD20-expressing cells. DuoBody-CD3xCD20 has a conventional IgG1 structure.

[0351] Two parent antibodies were produced as separate biological intermediates: IgG1-CD3-FEAL, a humanized IgG1λ, CD3ε-specific antibody with heavy and light chain sequences set forth in SEQ ID NOs: 24 and 25, respectively; and IgG1-CD20-FEAR, derived from the human IgG1κ CD20-specific antibody 7D8 with heavy and light chain sequences set forth in SEQ ID NOs: 26 and 27, respectively. Each parent antibody contains one of the complementary mutations in the CH3 domain (F405L and K409R, respectively) required for DuoBody molecule generation. The parent antibodies contained three additional mutations in the Fc region (L234F, L235E, and D265A; FEA). The parent antibodies were produced in mammalian Chinese hamster ovary (CHO) cell lines using standard suspension cell culture and purification techniques. DuoBody-CD3×CD20 was then produced by a controlled Fab arm exchange (cFAE) process (Labrijn et al., 2013; Labrijn et al., 2014; Gramer et al., 2013). The parent antibodies were mixed and subjected to controlled reducing conditions. This resulted in the separation of the parent antibodies, which reassembled under reoxidation. In this way, a highly pure preparation (approximately 93-95%) of DuoBody-CD3×CD20 was obtained. After further polishing / purification, a final product with near 100% purity was obtained. The theoretical extinction coefficient ε = 1.597 mL mg -1 cm -1 The concentration of DuoBody-CD3xCD20 was measured at absorbance at 280 nm using a chromatograph. The product has been given the international trade name epcoritamab.

[0352] Epcolitamab is manufactured as a clear, colorless to slightly yellow, sterile solution supplied as a concentrate for subcutaneous (SC) injection (5 mg / mL or 60 mg / mL). Epcolitamab contains a buffer and a tonicity agent. All excipients and their amounts in the formulation are pharmaceutically acceptable for SC injection products. The appropriate dose is reconstituted (reduced) to a volume of approximately 1 mL for SC injection.

[0353] Example 1: A Phase 1b / 2 Open-Label Safety and Efficacy Study of Epcolitamab in Relapsed / Refractory Chronic Lymphocytic Leukemia and Richter's Syndrome (RS) The objective of this Phase 1b / 2 study was to evaluate the safety and preliminary efficacy of single-agent epcolitamab in subjects with Richter's syndrome (RS). The study was an open-label, two-part (dose escalation and expansion), multicenter study conducted to evaluate the safety, tolerability, PK, pharmacodynamics, immunogenicity, and preliminary efficacy of single-agent epcolitamab in subjects aged 18 years or older with relapsed and / or refractory (R / R) chronic lymphocytic leukemia (CLL) or Richter's syndrome.

[0354] The clinical trial includes two parts: dose escalation (Part 1) and expansion (Part 2). The overall study design is disclosed in further detail in WO 2021 / 224499. The disclosure sets out the objectives of the dose escalation part, including identifying the recommended phase 2 dose (RP2D) and maximum tolerated dose (MTD). Epcolitamab was tested at two full dose levels: 24 mg and 48 mg. A step-up administration regimen (0.16 mg / 0.8 mg / 24 mg and 0.16 mg / 0.8 mg / 48 mg (priming / intermediate / full doses)) was applied.

[0355] An expansion cohort (Expansion Cohort 1) investigating the treatment of relapsed or refractory chronic lymphocytic leukemia (R / R CLL) is also disclosed in WO 2021 / 224499.

[0356] Finally, the disclosure of WO 2021 / 224499 includes preliminary results from data from the dose escalation phase, which suggest that epcolitamab is well tolerated in patients with R / R CLL at dose levels up to 48 mg and has promising clinical activity in patients with high-risk disease.

[0357] the purpose Expansion Cohort 2, Richter's syndrome The primary objective of this arm of Expansion Cohort 2 is to evaluate the preliminary efficacy of epcolitamab in subjects with Richter's syndrome (endpoint: ORR).

[0358] Secondary objectives of Expansion Cohort 2 are to evaluate the preliminary efficacy of epcolitamab (endpoints: overall response rate (ORR), duration of response (DOR), complete response (CR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and time to next anticancer therapy (TTNT)); to evaluate MRD status in peripheral blood and bone marrow (endpoint: occurrence of undetectable MRD); and to evaluate the safety and tolerability of epcolitamab (endpoints: adverse events (AEs), serious adverse events (SAEs), and AEs). The objectives of this study include the occurrence and severity of serious adverse events (SAEs), cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICAN), and tumor lysis syndrome (TLS), as well as the occurrence and dose intensity of dose interruptions and dose delays; to establish the pharmacokinetic (PK) and pharmacodynamic profile of epcolitamab (endpoints: PK parameters and pharmacodynamic parameters); and to evaluate the immunogenicity of epcolitamab (endpoint: occurrence of anti-drug antibodies (ADA) against epcolitamab).

[0359] Exploratory objectives of the expansion part include evaluating biomarkers predictive of clinical response to epcolitamab (endpoints: CD20 expression and immune populations, phenotypes and functions, and hematological assessments).

[0360] Overview of study design Expansion Cohort 2, Richter's syndrome The expansion part will enroll approximately 70 subjects with Richter's syndrome (RS).

[0361] Epcolitamab will be administered as a subcutaneous (SC) injection in 4-week cycles (i.e., 28 days) as indicated below until one or more of the discontinuation criteria are met.

[0362] Cycles 1-3: Days 1, 8, 15 and 22 (QW) Cycles 4-9: Days 1 and 15 (Q2W) Cycle 10 and beyond: Day 1 (Q4W) To mitigate the possibility of CRS, a step-up dosing regimen (i.e., a priming dose of 0.16 mg on day 1 of cycle 1, followed by an intermediate dose of 0.8 mg on day 8 of cycle 1, followed by a full dose of 48 mg on days 15 and 22 of cycle 1, and a full dose of 48 mg in subsequent cycles) will be used.

[0363] The primary efficacy endpoint of the expansion part is ORR, assessed using the iwCLL2018 criteria (Table 2). Secondary efficacy endpoints include DOR, CR, TTR, PFS, OS, and TTNT. The occurrence of MRD-negativity / undetectable MRD will also be assessed as a secondary efficacy endpoint. MRD assessment indicates the number of cancer cells still remaining in subjects who are in remission during or after treatment. Safety endpoints in the expansion part include the occurrence and severity of AEs / SAEs, tumor lysis syndrome (TLS), immune effector cell-associated neurotoxicity syndrome (ICANS), and CRS, and the occurrence of treatment interruptions and delays.

[0364] Inclusion criteria 1. Subjects must sign an ICF prior to any screening procedures to indicate that they understand the purpose and procedures of the trial and are willing to participate in the trial, prior to any other study-related assessments or procedures. If required by specific local or national regulations, each subject must sign a separate ICF if they consent to providing a sample for genomic biomarker analysis (DNA). If a subject refuses to consent to DNA studies in these specific regions, the subject is still eligible to participate in the trial.

[0365] 2. Subjects must be 18 years of age or older.

[0366] 3. Must have a clinical history of CLL / SLL with biopsy-proven transformation to aggressive lymphoma (i.e., DLBCL subtype).

[0367] 4. Deemed ineligible for chemoimmunotherapy at the investigator's discretion or refuses to undergo intensive chemotherapy.

[0368] 5. Must have measurable disease as determined by both of the following:

[0369] a. Fluorodeoxyglucose (FDG)-positron emission tomography (PET) CT scan showing a positive lesion consistent with the anatomic tumor site defined by CT (or MRI), and b. CT scan (or MRI) with two or more clearly defined lesions / nodes with a long axis greater than 1.5 cm and a short axis greater than 1.0 cm, or one clearly defined lesion / node with a long axis greater than 2.0 cm and a short axis greater than 1.0 cm.

[0370] 6. ECOG performance status score of 0, 1, or 2.

[0371] 7. Evidence of CD20 positivity at screening.

[0372] 8. Have acceptable test parameters as follows: [Table 3]

[0373] 8. Received a cumulative dose of corticosteroids less than 250 mg prednisone equivalent within 2 weeks prior to the first dose of epcolitamab.

[0374] 9. Subject must have availability of fresh bone marrow material at the time of screening.

[0375] 10. Females of reproductive potential must agree to use adequate contraception throughout the study and for 12 months after the final dose of epcolitamab. Adequate contraception is defined as highly effective contraception.

[0376] 11. Women of childbearing potential must have a negative serum (beta-hCG) pregnancy test at screening and a negative serum or urine pregnancy test before treatment administration on Day 1 of each cycle.

[0377] 12. Women must agree not to donate eggs (eggs, oocytes) for assisted reproduction purposes for the entire duration of the trial and until 12 months after their final treatment.

[0378] 13. Non-vasectomized men who are sexually active with women of childbearing potential must agree to use barrier methods of contraception, e.g., condoms with spermicide foam / gel / film / cream / suppository and occlusive caps (Diaphram or cervical cap) with spermicide foam / gel / film / cream / suppository in their partners, and must not donate sperm during the study and for 12 months after the last dose of epcolitamab.

[0379] 14. Subjects must be willing and able to comply with the prohibitions and restrictions set forth in this protocol.

[0380] Exclusion criteria 1. Diagnosis of Richter's syndrome, not a DLBCL subtype such as Hodgkin's lymphoma or prolymphocytic leukemia.

[0381] 2. Subjects underwent autologous HSCT within 3 months prior to the first dose of epcolitamab.

[0382] 3. Subject has received multiple prior lines of treatment for RS.

[0383] 4. Subject has received prior treatment with a CD3xCD20 bispecific antibody.

[0384] 5. Subject has undergone any prior allogeneic HSCT or solid organ transplant.

[0385] 6. Subject has received treatment with anti-cancer drugs, such as: a. A small molecule compound such as a BTK inhibitor, BCL2 inhibitor, or PI3K inhibitor within 5 half-lives prior to the first dose of epcolitamab; or b. Anti-CD20 mAb or chemotherapy within 2 weeks prior to the first dose of epcolitamab, or c. A radioactive or toxin-conjugated antibody or CAR-T cell therapy within 4 weeks or 5 half-lives (whichever is shorter) prior to the first dose of epcolitamab; or d. Treatment with an investigational drug within 4 weeks or 5 half-lives (whichever is shorter) prior to the first dose of epcolitamab.

[0386] 7. Subject has an autoimmune disease or other disease requiring permanent or high-dose immunosuppressive therapy.

[0387] 8. Subject has clinically significant cardiac disease, including (but not limited to): a. Unstable or uncontrolled diseases / conditions related to or affecting cardiac function, e.g., unstable angina, congestive heart failure III or IV [as classified by the New York Heart Association (see Appendix 3)], arrhythmias (CTCAE v5.0 grade 2 or higher) or clinically significant electrocardiogram (ECG) abnormalities, b. Myocardial infarction, intracranial hemorrhage, or stroke within the past 6 months; c. Screening 12-lead electrocardiogram showing a baseline QT interval (QTcF) greater than 480, corrected by the Fridericia formula.

[0388] 9. Subject received a live vaccine within 28 days prior to the first dose of epcolitamab.

[0389] 10. Subject has toxicity from prior anticancer therapy that has not improved to baseline levels or below Grade 1, excluding alopecia and peripheral neuropathy.

[0390] 11. Subject has a known central nervous system disorder at screening.

[0391] 12. Subject has any known past or present malignancy other than that diagnosed at the time of study entry, except for the following: a. Cervical cancer at stage 1B or below b. Noninvasive basal cell carcinoma or squamous cell carcinoma, c. Non-invasive superficial bladder cancer, d. Prostate cancer with a current PSA level of less than 0.1 ng / mL; e. Any curable cancer with a CR period of more than 2 years.

[0392] 13. Subject has suspected allergy, hypersensitivity or intolerance to epcolitamab or any of its excipients.

[0393] 14. Subject has undergone major surgery within 4 weeks prior to enrollment.

[0394] 15. Subject has the following known serologic history / positive result for Hepatitis B (unless immunized by vaccination or resolved natural infection, or passive immunization with immune globulin therapy): a positive test result for antibodies to hepatitis B core antigen (anti-HBc), and bNegative test result for antibodies to hepatitis B surface antigen (anti-HBs).

[0395] 16. Known history or ongoing uncured hepatitis C infection.

[0396] 17. Known history of seropositivity for HIV infection. Note: HIV testing will be requested at screening only if required by local health authority or facility standards.

[0397] 18. Subject is a woman who is pregnant or breastfeeding, or who plans to become pregnant while participating in this study or within 12 months of receiving the last dose of epcolitamab.

[0398] 19. Subjects are males who are planning to have children during the study or within 12 months of the last dose of epcolitamab.

[0399] 20. Subject has a condition where participation would not be in the subject's best interest (e.g., compromising health) or which may interfere with, limit, or confound the assessments specified in the protocol.

[0400] 21. Subject has an uncontrolled intercurrent illness, e.g., ongoing or active infection requiring intravenous antibiotic treatment, at the time of enrollment or within 2 weeks prior to the first dose of epcolitamab.

[0401] Premedication and CRS prophylaxis Premedication with corticosteroids, antihistamines, and antipyretics is mandatory, as listed in Table 5. For each dose of epcolitamab in Cycle 1, administration of corticosteroids for 4 consecutive days is mandatory to prevent / reduce the severity of symptoms from potential CRS, as listed in Table 5. For administration of epcolitamab in Cycle 2 and beyond, CRS prophylaxis with corticosteroids may be administered, if desired. Corticosteroid administration may be administered intravenously or orally at the recommended dose or an equivalent dose. [Table 4]

[0402] TIFF2025537529000007.tif120164

[0403] Supportive care for cytokine release syndrome CRS will be classified according to the ASTCT classification for CRS (Tables 7 and 8), and for the treatment of CRS, subjects should receive supportive care, including (but not limited to) the following:

[0404] Saline injection Systemic glucocorticosteroids, antihistamines, and antipyretics Blood pressure support (vasopressin, vasopressors) Support for low- and high-flow oxygen and positive pressure ventilation Intravenous administration of monoclonal antibodies against IL-6R, such as tocilizumab · Monoclonal antibodies against IL-6 (e.g., IV siltuximab if not responding to repeated doses of tocilizumab).

[0405] Administration of anakinra Blood product support, analgesics, skin and oral care, etc. should be in accordance with local guidelines and investigator discretion. [Table 5]

[0406] TIFF2025537529000009.tif205160

[0407] Prevention and treatment of tumor lysis syndrome For tumor lysis syndrome prophylaxis, subjects will receive a uric acid-lowering agent prior to epcolitamab administration, allopurinol at least 72 hours before the first epcolitamab dose, and rasburicase prior to the initiation of epcolitamab administration. Generous oral hydration should be administered before the first dose and hydration maintained throughout the infusion. Subjects will be reassessed for TLS risk category before subsequent doses.

[0408] Test evaluation Bone marrow evaluation Obtain a fresh bone marrow aspirate at screening (i.e., before day 1 of cycle 1, but within 21 days of day 1) and at the time of complete response (CR) or if clinically indicated. Obtain a fresh bone marrow biopsy at screening and at the time of CR or nodal partial response (nPR) or if clinically indicated. Bone marrow evaluation will include morphology and flow cytometry or immunohistochemistry.

[0409] Radiological evaluation For RS, at screening (i.e., within 3 weeks before the first dose of GEN3013), 18FAn FDG-PET CT scan (or CT / MRI and FDG-PET scan if PET CT scan is unavailable) should be performed. For subjects with FDG-affinity tumors at screening, all subsequent disease assessments should be performed with FDG-PET CT scans using a 5-point scale (Barrington et al., 2014). For subjects with FDG-inaffinity tumors or tumors with variable FDG affinity, an IV contrast-enhanced CT scan of the neck / chest / abdomen / pelvis / additional known lesions should be performed. The CT component of a PET CT scan may be used in place of a stand-alone CT / MRI scan only if the CT component is of similar diagnostic quality to a contrast-enhanced CT scan performed without PET. If a contrast-enhanced PET CT scan is unavailable, a stand-alone diagnostic CT / MRI scan and standard FDG-PET scan should be performed. If stand-alone CT and PET scanners are used and subjects undergo both scans on the same day, the PET scan should be performed before the IV contrast-enhanced CT scan to avoid affecting the PET results. The PET CT examination methodology (eg, administration of intravenous contrast) should remain consistent between screening and subsequent evaluations for any given subject.

[0410] The imaging assessment schedule for both dose escalation and expansion will be performed as detailed in the "Visit Assessment Schedule" (Section 1). Contrast-enhanced CT scan is the preferred imaging method. MRI may be used only if contrast-enhanced CT is medically contraindicated or if the frequency of CT scans exceeds local standards.

[0411] MRI may be used to evaluate disease sites that cannot be adequately imaged using CT (if MRI is preferred, it should be performed at screening and all subsequent response assessments). For all other disease sites, MRI is not a substitute for required CT scans of the neck, chest, abdomen, and pelvis.

[0412] If necessary, additional imaging evaluations may be performed at any time during the study at the discretion of the investigator to support efficacy assessments for the subject. If clinical suspicion of disease progression arises at any time, a physical examination and imaging evaluation should be performed promptly without waiting for the next scheduled imaging evaluation.

[0413] Minimal residual disease (MRD) assessment MRD will be assessed in blood by flow cytometry and next-generation sequencing. Blood samples will be requested at pre-determined time points after treatment initiation and upon CR. As an exploratory analysis, once subjects achieve CR, a portion of the aspirate taken to confirm CR will be used to assess MRD.

[0414] Assessment of disease response and disease progression Tumor response will be assessed based on imaging assessments to guide treatment decisions. Response assessments will be completed according to the Lugano criteria (Cheson et al., 2014, J Clin Oncol 32, 3059-3068), Table 2. Because local palliative radiotherapy for non-target lesions is permitted, if administered during the trial, these lesions should no longer be included in the response assessment.

[0415] Target and non-target lesions of the Lugano criteria (Cheson et al., 2014) Target lesions should consist of up to six of the largest major lymph nodes, lymph node masses, or other lymphoma lesions measurable in two diameters, preferably from different body regions representative of the subject's overall disease burden (including mediastinal and retroperitoneal lesions, if applicable). At baseline, the longest diameter (LDi) of measurable lymph nodes must be greater than 15 mm. Measurable extranodal lesions may be included among the six representative target lesions. At baseline, the LDi of measurable extranodal lesions should be greater than 10 mm. All other lesions (including lymph nodes, extranodal, and evaluable lesions) should be followed as non-target lesions (e.g., skin, GI, bone, spleen, liver, kidney, pleural or pericardial effusions, ascites, bone, bone marrow).

[0416] mitotic and fusion lesions Lesions may split or fuse over time. In the case of splitting lesions, the individual PPDs of the lymph nodes should be summed to represent the PPD (product of perpendicular diameters) of the splitting lesion. This PPD is added to the sum of the PPDs of the remaining lesions to measure response. If subsequent growth of any or all of these individual lymph nodes occurs, the nadir of each individual lymph node is used to determine progression. In the case of confluent lesions, the PPD of the confluent mass should be compared to the sum of the PPDs of the individual lymph nodes; a greater than 50% increase in the PPD of the confluent mass compared to the sum of the individual lymph nodes is required to indicate progressive disease (PD). The LDi and smallest diameter (SDi) are no longer required to determine progression.

[0417] The endpoint definition is as follows:

[0418] Overall response rate (ORR) is defined as the proportion of subjects who achieve a PR or CR response before the initiation of subsequent treatment.

[0419] Time to response (TTR) is defined as the time from the first dose of epcolitamab to the first documented PR or CR in responders.

[0420] Duration of response (DOR) is defined as the time from the first documented PR or CR to the date of disease progression or death, whichever occurs first, in responders.

[0421] Progression-free survival (PFS) is defined as the time from the date of first administration of epcolitamab to the date of disease progression or death, whichever occurs first.

[0422] Overall survival (OS) was defined as the time from the first administration of epcolitamab to the date of death.

[0423] The MRD-negativity rate is defined as the proportion of subjects with at least one undetectable MRD result based on a specific threshold before initiation of subsequent treatment.

[0424] Clinical Safety Evaluation Safety will be assessed by measuring adverse events, clinical laboratory results, ECG, vital signs, physical examination findings, and ECOG performance status. Additionally, immune effector cell-associated neurotoxicity syndromes (e.g., those described by Lee et al., Biol Blood Marrow Transplant 2019;25:625-638), systemic symptoms (B symptoms), tumor flare response, and survival will also be assessed.

[0425] Immunophenotyping To monitor changes associated with epcolitamab treatment, absolute B and T cell counts are measured in fresh whole blood using flow cytometry. T cell activation and exhaustion phenotypes are assessed using flow cytometry and markers to assess the correlation of such markers with epcolitamab drug-target binding, therapeutic efficacy, and / or safety. Additional immunophenotypes of circulating immune cells (e.g., levels of regulatory T cells, which can suppress T cell function) are measured in fresh whole blood using flow cytometry to assess the correlation of such markers with T cell activation / exhaustion phenotypes, subject response, and epcolitamab MOA.

[0426] Cytokine and endothelial activation marker analysis Because T cell activation after the first dose of epcolitamab can lead to cytokine release and cause CRS, cytokine concentrations are closely monitored. Levels of cytokines such as IL-2, IL-15, IL-6, IL-8, IL-10, IFNγ, and / or TNFα are measured in plasma samples using array-based ligand binding assays. Additional cytokines may also be measured to assess the association of such markers with adverse events and outcomes associated with epcolitamab treatment.

[0427] Preliminary results: The first patient was enrolled on November 17, 2021.

[0428] Data cutoff July 15, 2022: Ten patients with RS (median age 69.5 years, range 53-79 years) received 48 mg of epcolitamab and were followed for at least 12 weeks. The median time from RS diagnosis to first epcolitamab administration was 0.03 years (range 0.0-0.1 years). Prior therapies for RS included rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), rituximab, dexamethasone, cytarabine, and cisplatin (R-DHAP), and venetoclax plus dose-adjusted rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH). Fifty percent of patients received epcolitamab as first-line treatment for RS. The median treatment duration was 2.5 months (range, 0.5-6.5 months), and 5 (50%) patients were currently receiving ongoing treatment. The most common related treatment-emergent adverse events (TEAEs) of any grade were CRS (90%; grade 1 in 30% and grade 2 in 60%), anemia (30%), diarrhea (40%), hypophosphatemia (10%), injection site reactions (30%), and thrombocytopenia (30%). Notable grade 3-4 TEAEs included neutropenia (n=4; grade 3 in 2 patients and grade 4 in 2 patients), anemia (n=2), and COVID-19 (n=2). Most CRS events were related to the administration of the first full dose of epcolitamab. All CRS events resolved (median time to resolution, 3 days). No patients discontinued treatment due to CRS, and 7 patients received tocilizumab. No cases of ICANS were observed. Clinical tumor lysis syndrome (grade 2) occurred in one patient and resolved within 3 days. No patients discontinued treatment due to AEs. Two patients died of disease progression. Antitumor activity was observed early [the majority of responses were observed at the first evaluation (week 6)], with an overall response rate of 60% and a complete response rate of 50%.

[0429] Data cutoff: September 8, 2022 (efficacy) / September 16, 2022 (safety) A total of 10 patients in the Richter cohort received 48 mg of epcolitamab and were evaluable for response. The median treatment duration was 3.5 months (range: 0.5-9.3 months). The median number of 28-day cycles of epcolitamab was 4 (range: 1-11). Key patient characteristics are shown in Tables 9 and 10 below, and treatment history is shown in Tables 11 and 12. [Table 6]

[0430] TIFF2025537529000011.tif197161

[0431] The most common associated treatment-emergent adverse events are shown in Figure 1. Adverse events were primarily low-grade and included CRS. No ICANS events were observed. One case of clinical tumor lysis syndrome (grade 2) was observed, which resolved after 3 days. One grade 5 (fatal) treatment-emergent adverse event (TEAE) was observed (deterioration of general health in the setting of progressive disease; unrelated to epcolitamab). Six patients experienced dose delays due to TEAEs. No TEAEs led to study discontinuation.

[0432] CRS events were recorded as shown in Table 13. CRS events by treatment period are shown in Figure 2. The onset of CRS was predictable, with most cases occurring after the administration of the first full dose of epcolitamab. No CRS events of grade 3 or higher were observed. All CRS events resolved, and none led to treatment discontinuation. [Table 7]

[0433] The depth and duration of response are shown in Figure 3. The median time to response was 1.3 months (range: 1.1-2.4 months). The median time to complete response was 1.4 months (range: 1.1-2.8 months). Best overall response data are shown in Table 14 below. [Table 8]

[0434] Tumor shrinkage from baseline (best overall response) is shown in Figure 4.

[0435] Figure 5 shows a clinical case study of RS-DLBCL.

[0436] Patient History: 76-year-old man Diagnosed with SLL in July 2019 and started ibrutinib Converted to RS-DLBCL in October 2020 Treated RS-DLBCL with 3 cycles of R-CHOP; mixed response Epcolitamab treatment: Initial dose: SPD=105cm 2 CR at weeks 6, 12, 17, 23, 36, 48, 62, and 76: DS=1, Sum of Products of Diameters (SPD)=2.8 cm 2 The patient has been in a sustained CR for over 70 weeks and is currently on treatment (last dose was C22D1) As of August 15, 2023, 30 subjects had been treated with at least one dose of epcolitamab. The observed overall response rate and complete metabolic response rate were similar to results from the September 2022 cutoff and demonstrated a consistent, manageable, and tolerable safety profile.

[0437] Conclusion: Based on data from the data cutoffs of September 8, 2022 (efficacy) and September 16, 2022 (safety), the following conclusions were drawn: In patients with RS, SC epcolitamab demonstrated a manageable safety profile with low-grade CRS events. Most CRS events occurred in cycle 1 after the first full dose of epcolitamab. All resolved, and none led to treatment discontinuation. This safety profile was consistent with previous reports of epcolitamab monotherapy, and no new safety signals were reported. Preliminary efficacy findings indicate that SC epcolitamab provides promising single-agent activity in RS-DLBCL, with high overall and complete response rates observed, with most responses observed at the first (week 6) evaluation.

[0438] Based on data from the September 2022 data cutoff, the conclusion remains favorable, with epcolitamab demonstrating promising activity, with high overall response rates and CMR and a tolerable safety profile.

[0439] Overall response rate (ORR): 60%; Complete metabolic response rate (CMR): 50% Low-grade cytokine release syndrome (CRS) only; all resolved No ICANS events One case of grade 2 CTLS, which resolved after 3 days There were no treatment discontinuations due to treatment-emergent adverse events (TEAEs). As of August 15, 2023, epcolitamab continues to demonstrate high preliminary ORR and CR rates with a manageable and tolerable safety profile, demonstrating that epcolitamab has the potential to be an effective, convenient, and tolerable treatment option with a favorable benefit-risk profile for patients with RS. [Table 9]

[0440] TIFF2025537529000015.tif249160

[0441] TIFF2025537529000016.tif113161

Claims

1. (i) a first binding arm comprising a first antigen-binding region that binds to human CD3ε (epsilon) and that includes a variable heavy (VH) region and a variable light (VL) region, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 6, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO: 7; and (ii) a second binding arm comprising a VH region and a VL region, the second binding arm comprising a second antigen-binding region that binds to human CD20, wherein the VH region comprises the CDR1, CDR2, and CDR3 sequences present in the VH region sequence of SEQ ID NO: 13, and the VL region comprises the CDR1, CDR2, and CDR3 sequences present in the VL region sequence of SEQ ID NO:

14.

1. A method of treating Richter's syndrome (RS) in a human subject, comprising administering to the subject a bispecific antibody comprising:

2. 10. The method of claim 1, wherein the bispecific antibody is administered at a dose of 24 mg.

3. 10. The method of claim 1, wherein the bispecific antibody is administered at a dose of 48 mg.

4. The method of any one of claims 1 to 3, wherein the bispecific antibody is administered once a week (weekly administration).

5. 5. The method of claim 4, wherein the weekly administration occurs in 2.5 28-day cycles.

6. 6. The method of claim 4 or 5, wherein the bispecific antibody is administered weekly followed by once every two weeks (biweekly administration).

7. 7. The method of claim 6, wherein the biweekly administration occurs in six 28-day cycles.

8. 8. The method of claim 6 or 7, wherein the bispecific antibody is administered every other week, followed by once every four weeks.

9. 9. The method of any one of claims 4 to 8, wherein a priming dose of the bispecific antibody is administered in cycle 1 of a 28 day cycle prior to administration of the first weekly dose of 12 to 60 mg.

10. 10. The method of claim 9, wherein a priming dose is administered two weeks before the first weekly dose of 12 to 60 mg.

11. 11. The method of claim 9 or 10, wherein the priming dose is in the range of 0.05 to 0.35 mg.

12. The method of any one of claims 9 to 11, wherein the priming dose is at or about 0.16 mg.

13. 13. The method of any one of claims 9 to 12, wherein an intermediate dose of the bispecific antibody is administered after the priming dose and before the first weekly dose of 12 to 60 mg.

14. 14. The method of claim 13, wherein a priming dose is administered on day 1 and an intermediate dose is administered on day 8 prior to administration of the first weekly dose of 12 to 60 mg on days 15 and 22 of cycle 1.

15. 15. The method of claim 13 or 14, wherein the intermediate dose is in the range of 0.6 to 1.2 mg.

16. 16. The method of any one of claims 13 to 15, wherein the intermediate dose is at or about 0.8 mg.

17. The bispecific antibody is administered in a 28 day cycle, wherein: e) In cycle 1, a priming dose is administered on day 1, an intermediate dose is administered on day 8, and full doses of 12-60 mg are administered on days 15 and 22; f) in cycles 2-3, full doses of 12-60 mg are administered on days 1, 8, 15, and 22; g) in cycles 4-9, a full dose of 12-60 mg is administered on days 1 and 15; and h) The method of any one of claims 13 to 16, wherein a full dose of 12 to 60 mg is administered on day 1 in cycle 10 and subsequent cycles.

18. 18. The method of claim 17, wherein the full dose is at or about 24 mg.

19. 18. The method of claim 17, wherein the full dose is at or about 48 mg.

20. The method of any one of claims 1 to 19, wherein the bispecific antibody is administered subcutaneously.

21. 21. The method of any one of claims 1 to 20, wherein the subject has a clinical history of CLL / SLL with transformation to aggressive lymphoma, for example of the DLBCL subtype.

22. The method according to any one of claims 1 to 21, wherein Richter's syndrome is of the DLBCL subtype.

23. 23. The method of any one of claims 1 to 22, wherein the subject has received one or more, such as at least two, previous lines of treatment for chronic lymphocytic leukemia (CLL) and / or small lymphocytic lymphoma (SLL).

24. 10. The method of any one of the preceding claims, wherein the previous line of treatment for CLL and / or SLL comprises chemoimmunotherapy.

25. 10. The method of any one of the preceding claims, wherein the previous line of treatment for CLL and / or SLL includes therapy using a targeted agent, such as a BCL2 inhibitor or a BTK inhibitor.

26. 10. The method of any one of the preceding claims, wherein the previous line of treatment for CLL and / or SLL comprises CAR T-cell therapy.

27. If the subject has had previous treatment for Richter's syndrome, e.g. i) Rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); ii) rituximab in combination with dexamethasone, cytarabine and cisplatin (R-DHAP); and iii) Venetoclax in combination with rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (VR-EPOCH) The method of any one of claims 1 to 23, wherein the patient has received a previous treatment selected from the group consisting of:

28. 28. The method of any one of claims 1 to 27, wherein the subject achieves a complete or partial metabolic response.

29. 28. The method of any one of claims 1 to 27, wherein the subject achieves a complete response, a partial response, or stable disease.

30. 27. The method of any one of claims 1 to 26, wherein the subject receives epcolitamab as a first line treatment for Richter's syndrome.

31. 31. The method of any one of claims 1 to 30, wherein the subject achieves a complete or partial metabolic response.

32. 31. The method of any one of claims 1 to 30, wherein the subject achieves a complete response, a partial response, or stable disease.

33. 33. The method of any one of claims 1 to 26 and 30 to 32, wherein said method is a first line treatment for Richter's syndrome.

34. 30. The method of any one of claims 21 to 29, wherein the subject has resistant and / or recurrent Richter's syndrome after undergoing said previous treatment.

35. 35. The method of any one of claims 1 to 34, wherein the subject is treated with a prophylactic treatment against cytokine release syndrome (CRS).

36. 36. The method of claim 35, wherein the prophylactic treatment comprises administering a corticosteroid to the subject.

37. 37. The method of claim 35 or 36, wherein the corticosteroid is administered on the same day as the bispecific antibody.

38. 38. The method of claim 37, further comprising administering a corticosteroid on days 2, 3, and 4 after administration of the bispecific antibody.

39. 39. The method of any one of claims 36 to 38, wherein the corticosteroid is prednisolone.

40. 40. The method of claim 39, wherein prednisolone is administered at an intravenous dose of 100 mg or its equivalent (including oral doses).

41. 41. The method of any one of claims 1 to 40, wherein the subject is premedicated to reduce any reaction to the injection.

42. 42. The method of claim 41, wherein the premedication comprises an antihistamine.

43. 43. The method of claim 42, wherein the antihistamine is diphenhydramine.

44. 44. The method of claim 43, wherein diphenhydramine is administered in a 50 mg intravenous or oral dose or equivalent.

45. 45. The method of any one of claims 41 to 44, wherein the premedication comprises an antipyretic.

46. 46. ​​The method of claim 45, wherein the antipyretic is acetaminophen.

47. 47. The method of claim 46, wherein acetaminophen is administered at an oral dose of 560 to 1000 mg, or its equivalent.

48. The method of any one of claims 41 to 47, wherein the premedication is administered on the same day as the administration of the bispecific antibody.

49. The method according to any one of claims 35 to 48, wherein prophylactic treatment is performed in cycle 1.

50. The method according to any one of claims 41 to 49, wherein premedication is administered in cycle 1.

51. 51. The method of claim 49 or 50, wherein if the subject experiences CRS greater than Grade 1 after the final administration of the bispecific antibody in Cycle 1, then prophylaxis is administered in Cycle 2.

52. 52. The method of claim 51, wherein prophylaxis is continued in a subsequent cycle if the subject experiences CRS greater than grade 1 upon the final administration of the bispecific antibody in the previous cycle.

53. The method according to any one of claims 41 to 52, wherein premedication is administered in cycle 2.

54. 54. The method of claim 53, wherein premedication is administered in subsequent cycles.

55. 55. The method of any one of claims 1 to 54, wherein an antibiotic is administered to the subject if the subject develops grade 1 CRS.

56. 55. The method of any one of claims 1 to 54, wherein a vasopressor is administered to the subject if the subject develops Grade 2 or Grade 3 CRS.

57. 55. The method of any one of claims 1 to 54, wherein at least two vasopressor agents are administered to the subject if the subject develops grade 4 CRS.

58. 58. The method of any one of claims 1 to 57, wherein tocilizumab is administered to the subject if the subject develops Grade 2, Grade 3, or Grade 4 CRS.

59. 59. The method of claim 58, further comprising administering a steroid to the subject.

60. 60. The method of claim 59, wherein the steroid is dexamethasone.

61. 60. The method of claim 59, wherein the steroid is methylprednisolone.

62. The method of any one of claims 58 to 61, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an anti-IL-6 antibody (e.g., siltuximab).

63. 62. The method of any one of claims 58 to 61, wherein if the subject is resistant to tocilizumab, tocilizumab is switched to an IL-1R antagonist (e.g., anakinra).

64. 64. The method of any one of claims 1 to 63, wherein the subject is treated with prophylactic treatment against tumor lysis syndrome (TLS).

65. 65. The method of claim 64, wherein the prophylactic treatment against TLS comprises administering one or more uric acid lowering agents prior to administration of the bispecific antibody.

66. 66. The method of claim 65, wherein the one or more uric acid lowering agents comprise rasburicase and / or allopurinol.

67. 67. The method of any one of claims 1 to 66, wherein the subject achieves a complete response, a partial response, or stable disease.

68. (i) the first antigen-binding region comprises VHCDR1, VHCDR2, and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 1, 2, and 3, respectively, and VLCDR1, VLCDR2, and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 4, SEQ ID NO: GTN, and SEQ ID NO: 5, respectively; and (ii) the second antigen-binding region comprises VHCDR1, VHCDR2 and VHCDR3 comprising the amino acid sequences set forth in SEQ ID NOs: 8, 9 and 10, respectively, and VLCDR1, VLCDR2 and VLCDR3 comprising the amino acid sequences set forth in SEQ ID NO: 11, sequence DAS and SEQ ID NO: 12, respectively.

69. (i) the first antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO: 6 and a VL region comprising the amino acid sequence of SEQ ID NO: 7; and (ii) the second antigen-binding region comprises a VH region comprising the amino acid sequence of SEQ ID NO: 13 and a VL region comprising the amino acid sequence of SEQ ID NO:

14. The method of any one of claims 1 to 68.

70. 69. The method of any one of claims 1 to 68, wherein the first binding arm of the bispecific antibody is derived from a humanized antibody, preferably a full-length IgG1, λ (lambda) antibody.

71. 71. The method of claim 70, wherein the first binding arm of the bispecific antibody comprises a lambda light chain constant region comprising the amino acid sequence set forth in SEQ ID NO:

22.

72. 72. The method of any one of claims 1 to 71, wherein the second binding arm of the bispecific antibody is derived from a human antibody, preferably a full-length IgG1, κ (kappa) antibody.

73. 73. The method of claim 72, wherein the second binding arm comprises a kappa light chain constant region comprising the amino acid sequence set forth in SEQ ID NO:

23.

74. The method of any one of claims 1 to 73, wherein the bispecific antibody is a full-length antibody having a human IgG1 constant region.

75. 75. The method of any one of claims 1 to 74, wherein the bispecific antibody comprises an inactive Fc region.

76. The method of any one of claims 1 to 75, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to positions L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively.

77. 77. The method of any one of claims 1 to 76, wherein the bispecific antibody comprises a first heavy chain and a second heavy chain, wherein in the first heavy chain, the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L and in the second heavy chain, the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

78. A bispecific antibody comprises a first heavy chain and a second heavy chain, wherein: (i) in both the first heavy chain and the second heavy chain, the amino acids at positions corresponding to L234, L235, and D265 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 are F, E, and A, respectively; and (ii) in the first heavy chain, the amino acid at the position corresponding to F405 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is L, and in the second heavy chain, the amino acid at the position corresponding to K409 in the human IgG1 heavy chain constant region of SEQ ID NO: 15 is R, or vice versa.

79. 79. The method of claim 78, wherein the bispecific antibody comprises a heavy chain constant region comprising the amino acid sequences of SEQ ID NOs: 19 and 20.

80. 80. The method of any one of claims 1 to 79, wherein the bispecific antibody comprises heavy and light chains comprising the amino acid sequences set forth in SEQ ID NOs: 24 and 25, respectively, and heavy and light chains comprising the amino acid sequences set forth in SEQ ID NOs: 26 and 27, respectively.

81. The method of any one of claims 1 to 80, wherein the bispecific antibody comprises heavy and light chains consisting of the amino acid sequences of SEQ ID NOs: 24 and 25, respectively, and heavy and light chains consisting of the amino acid sequences of SEQ ID NOs: 26 and 27, respectively.

82. 82. The method of any one of claims 1 to 81, wherein the bispecific antibody is epcolitamab or a biosimilar thereof.

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