Methods of treatment using antibodies to BCMA and CD3

Abstract

The present invention relates to methods of treating patients with disorders associated with BCMA expression (e.g., BCMA-expressing B-cell cancers such as multiple myeloma) using a dose-escalating administration regimen with multispecific (e.g., bispecific) antibodies that bind to CD3 and BCMA.

Description

[Technical Field]

[0001] This application claims the benefit of priority to European Patent Application No. 19207293.2, filed November 5, 2019, and European Patent Application No. 20179573.9, filed June 11, 2020, the contents of each of which are incorporated herein by reference in their entirety.

[0002] Citation of Electronically Submitted Sequence Listings This application incorporates by reference the sequence listing submitted in a text file entitled "14247-608-228_Sequence_Listing.TXT", created on November 4, 2020, and 68,146 bytes in size.

[0003] FIELD OF THE INVENTION The present invention relates to antibodies against BCMA and CD3 for use in the treatment of disorders associated with BCMA expression (e.g., BCMA-expressing B-cell cancers such as multiple myeloma). [Background technology]

[0004] background Multispecific (e.g., bispecific) antibodies against BCMA and CD3 are known and have shown remarkable therapeutic effects. However, these antibodies may be associated with side effects, particularly cytokine release syndrome (CRS). Therefore, there is a need for a dosing regimen that achieves a favorable benefit-risk profile. Summary of the Invention

[0005] overview The present invention relates to methods of treating patients with disorders associated with BCMA expression (e.g., BCMA-expressing B-cell cancers such as multiple myeloma) using a dose-escalating administration regimen with multispecific (e.g., bispecific) antibodies that bind to CD3 and BCMA, which administration regimen significantly reduces toxicity due to decreased cytokine release.

[0006]

[0013] Accordingly, in one aspect, the present invention provides a method of treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises administering to a subject a multispecific (e.g., bispecific) antibody that binds BCMA and CD3, as follows: (i) an initiation phase in which one or more initial doses of a multispecific (e.g., bispecific) antibody are administered to the patient; and (ii) a maintenance phase, in which an initial maintenance dose of a multispecific (e.g., bispecific) antibody is administered to the patient, optionally followed by at least one additional maintenance dose of the multispecific (e.g., bispecific) antibody; wherein each maintenance dose is greater than one or more starting doses; This includes administering the compound in a dosing regimen.

[0007] In another aspect, the present invention provides multispecific (e.g., bispecific) antibodies that bind BCMA and CD3 for use in treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises administering the multispecific (e.g., bispecific) antibody to one of the following: (i) an initiation phase in which one or more initial doses of a multispecific (e.g., bispecific) antibody are administered to the patient; and (ii) a maintenance phase in which an initial maintenance dose of a multispecific (e.g., bispecific) antibody is administered to the patient, followed, if necessary, by at least one additional maintenance dose of the multispecific (e.g., bispecific) antibody. wherein each maintenance dose is greater than one or more starting doses; This includes administering the compound in a dosing regimen.

[0008] In some embodiments, the one or more starting doses comprise a fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, or about 2.5 mg to 3.5 mg, e.g., about 3 mg. In preferred embodiments, the one or more starting doses comprise a single fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, or about 2.5 mg to 3.5 mg, e.g., about 3 mg.

[0009] In certain embodiments, the initial maintenance dose may be administered at a flat dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; about 5.5 mg to 6.5 mg, for example, about 6 mg.

[0010] In some embodiments, at least one additional maintenance dose is the same amount as the initial maintenance dose. In some embodiments, the maintenance dose may be administered as a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; about 5.5 mg to 6.5 mg, e.g., about 6 mg. Thus, in some embodiments, the starting dose of a multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, and each maintenance dose is a fixed dose of about 6 mg.

[0011] In some embodiments, the at least one additional maintenance dose is greater than the initial maintenance dose. In some embodiments, the initial maintenance dose may be administered as a fixed dose of about 4.5 mg to about 7.5 mg; about 5 mg to about 6 mg; or about 5.5 mg to about 6.5 mg, e.g., about 6 mg, and the at least one additional maintenance dose is a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; or about 9.5 mg to about 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose of a multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, the initial maintenance dose is a fixed dose of about 6 mg, and the at least one additional maintenance dose is a fixed dose of about 10 mg.

[0012] In some embodiments, the one or more starting doses include a flat dose of about 4.5 mg to about 7.5 mg, about 5 mg to about 7 mg, or about 6.5 mg to about 7.5 mg, e.g., about 6 mg. In some embodiments, the one or more starting doses include a single flat dose of about 4.5 mg to 7.5 mg, about 5 mg to 7 mg, or about 5.5 mg to 6.5 mg, e.g., about 6 mg.

[0013] In certain embodiments, the initial maintenance dose may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, for example, about 10 mg.

[0014] In some embodiments, at least one additional maintenance dose is the same amount as the initial maintenance dose. In some embodiments, the maintenance doses may be administered as a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; or about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose of a multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg, and each maintenance dose is a fixed dose of about 10 mg.

[0015] In some embodiments, the at least one additional maintenance dose is greater than the initial maintenance dose. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg, the initial maintenance dose is a fixed dose of about 10 mg, and the at least one additional maintenance dose is a fixed dose of greater than about 10 mg.

[0016] In certain embodiments, the patient has developed or is at risk of developing an adverse event associated with administration of a multispecific (e.g., bispecific) antibody, wherein treatment comprises one of the following: a) steroids, such as corticosteroids; b) an antagonist of a cytokine receptor selected from among GM-CSF, IL-10, IL-10R, IL-6, IL-6 receptor (IL-6R), IFNγ, IFNGR, IL-2, IL-2R / CD25, MCP-1, CCR2, CCR4, MIPIβ, CCR5, TNFα, TNFR1, IL-1, and IL-1Rα / IL-1β, or a cytokine, wherein the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid; c) molecules that decrease regulatory T cell (Treg) populations, such as cyclophosphamide; d) antipyretics, analgesics and / or antibiotics; and / or e) seizure prevention drugs, e.g. levetiracetam The method further comprises administering

[0017] In some embodiments, the corticosteroid is dexamethasone or methylprednisolone. In some embodiments, the antagonist is tocilizumab and / or siltoximab.

[0018] In some embodiments, multispecific (e.g., bispecific) antibodies are administered intravenously or subcutaneously. In a preferred embodiment, multispecific (e.g., bispecific) antibodies are administered intravenously.

[0019] In some embodiments, the disorder associated with BCMA expression is a BCMA-expressing B-cell cancer, such as multiple myeloma. In some embodiments, the multispecific (e.g., bispecific) antibody is administered to the patient as monotherapy. In some embodiments, the multispecific (e.g., bispecific) antibody is administered to the patient as combination therapy with one or more additional therapeutic agents. In some embodiments, the one or more additional therapeutic agents are selected from the group consisting of thalidomide and its immunotherapeutic derivatives, anti-CD38 antibodies, anti-PD-1 antibodies, anti-PD-L1 antibodies, gamma secretase inhibitors (GSIs), anti-BCMA antibody drug conjugates, and anti-BCMA CAR T-cell therapy.

[0020] In certain embodiments, a "subject" or "patient" is a human.

[0021] In some embodiments, the multispecific (e.g., bispecific) antibody comprises a CDR3H region of SEQ ID NO: 17 and a CDR3L region of SEQ ID NO: 20, and the following: a) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 23, and the CDR2L region of SEQ ID NO: 24; b) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 25, and the CDR2L region of SEQ ID NO: 26; c) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 27, and the CDR2L region of SEQ ID NO: 28; d) the CDR1H region of SEQ ID NO: 29 and the CDR2H region of SEQ ID NO: 30, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; e) the CDR1H region of SEQ ID NO: 34 and the CDR2H region of SEQ ID NO: 35, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; f) the CDR1H region of SEQ ID NO: 36 and the CDR2H region of SEQ ID NO: 37, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32, and g) the CDR1H region of SEQ ID NO: 15 and the CDR2H region of SEQ ID NO: 16, the CDR1L region of SEQ ID NO: 18, and the CDR2L region of SEQ ID NO: 19 The present invention also includes an anti-BCMA antibody or antigen-binding fragment thereof comprising a combination of CDR1H, CDR2H, CDR1L and CDR2L regions selected from the group consisting of:

[0022] In some embodiments, the anti-BCMA antibody or antigen-binding fragment thereof is a) the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 12 b) the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 13 c) the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 14 d) the VH region of SEQ ID NO: 38 and the VL region of SEQ ID NO: 12 e) a VH region of SEQ ID NO: 39 and a VL region of SEQ ID NO: 12; f) a VH region of SEQ ID NO: 40 and a VL region of SEQ ID NO: 12, or g) the VH region of SEQ ID NO: 9 and the VL region of SEQ ID NO: 11 The VH and VL are selected from the group consisting of:

[0023] In a particularly preferred embodiment, the anti-BCMA antibody or antigen-binding fragment thereof comprises a VH region of SEQ ID NO:10 and a VL region of SEQ ID NO:14.

[0024] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-CD3 antibody or antigen-binding fragment thereof comprising a variable domain VH comprising the heavy chain CDRs of SEQ ID NOs: 1, 2, and 3 as heavy chain CDR1H, CDR2H, and CDR3H, respectively, and a variable domain VL comprising the light chain CDRs of SEQ ID NOs: 4, 5, and 6 as light chain CDR1L, CDR2L, and CDR3L, respectively. In some embodiments, the anti-CD3 antibody or antigen-binding fragment thereof comprises the VH region of SEQ ID NO: 7 and the VL region of SEQ ID NO: 8.

[0025] In particularly preferred embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 14, and an anti-CD3 antibody, or antigen-binding fragment thereof, comprising the VH region of SEQ ID NO: 7 and the VL region of SEQ ID NO: 8.

[0026] In some embodiments, the multispecific antibody is a bispecific antibody. In some embodiments, the bispecific antibody is bivalent (1 + 1 format). In some embodiments, the bivalent bispecific antibody has the format: CD3 Fab - BCMA Fab (i.e., when Fc is absent). Alternatively, the bivalent bispecific antibody may have the format: Fc - CD3 Fab - BCMA Fab; Fc-BCMAFab-CD3Fab; or BCMA Fab - Fc - CD3 Fab (i.e., when Fc is present). In a preferred embodiment, the bivalent bispecific antibody has the format: BCMA Fab - Fc - CD3 Fab. In some embodiments, the bispecific antibody is trivalent (2 + 1 format). In some embodiments, the trivalent bispecific antibody has the format: CD3 Fab - BCMA Fab - BCMA Fab; or BCMA Fab - CD3 Fab - BCMA Fab (i.e., when Fc is absent). Alternatively, the trivalent bispecific antibody may have the format: BCMA Fab - Fc - CD3 Fab - BCMA Fab; BCMA Fab - Fc - BCMA Fab - CD3 Fab; or CD3 Fab - Fc - BCMA Fab - BCMA Fab (i.e., when Fc is present). In a preferred embodiment, the trivalent bispecific antibody has the format BCMA Fab - Fc - CD3 Fab - BCMA Fab.

[0027] In one embodiment, the anti-CD3 Fab comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1.

[0028] In some embodiments, the CH1 domain of the anti-BCMA Fab fragment comprises the amino acid modifications K147E / D and K213E / D (numbered according to EU numbering), and the corresponding immunoglobulin light chain comprising a CL domain with the amino acid modifications E123K / R / H and Q124K / R / H (numbered according to Kabat).

[0029] In some embodiments, the multispecific (e.g., bispecific) antibody further comprises an Fc. In some embodiments, the Fc is an IgG1 Fc. In some embodiments, the (e.g., IgG1) Fc comprises a first Fc chain comprising a first constant domain, CH2, and CH3, and a second Fc chain comprising a second constant domain, CH2, and CH3, wherein: a) the first CH3 domain contains the modifications T366S, L368A and Y407V, or conservative substitutions thereof (numbered according to EU numbering); and b) The second CH3 domain contains the modification T366W, or a conservative substitution thereof (numbering according to EU numbering).

[0030] In some embodiments, the (e.g., IgG1) Fc comprises: a) the modifications L234A, L235A and P329G (numbering according to EU numbering), and / or b) Modifications D356E and L358M (numbering according to EU numbering) Includes.

[0031] In a further embodiment, the bispecific antibody according to the invention has the following SEQ ID NO: i. 83A10-TCBcv: 45, 46, 47(x2), 48 (Figure 2A) ii. 21-TCBcv: 48, 49, 50, 51 (x2) (Figure 2A) iii. 22-TCBcv: 48, 52, 53, 54 (x2) (Figure 2A) iv. 42-TCBcv: 48, 55, 56, 57 (x2) (Figure 2A) Includes.

[0032] In a preferred embodiment, the bispecific antibody of the invention is 42-TCBcv.

[0033] Aspects and aspects of the present invention are set out in the accompanying claims. These and other aspects and aspects of the present invention are also described herein. [Brief explanation of the drawings]

[0034] The present invention can now be described in more detail with reference to the accompanying drawings. [Figure 1] Figure 1 shows different formats of bispecific, bivalent antibodies for use in the present invention, which contain Fab fragments that bind to CD3 and BCMA in the format Fab BCMA-Fc-Fab CD3. The CD3 Fab may contain a VH-VL crossover to reduce light chain mispairing and side products. Introducing the amino acid substitution "RK / EE" into CL-CH1 can reduce light chain mispairing / side products during manufacturing. The CD3 Fab and BCMA Fab may be linked to each other with a flexible linker. [Figure 2] Figure 2 shows different formats of bispecific trivalent antibodies for use in the present invention, which contain Fab fragments that bind to CD3 and BCMA in the following formats: Fab BCMA-Fc-Fab CD3-Fab BCMA (A, B); Fab BCMA-Fc-Fab BCMA-Fab CD3 (C, D). The CD3 Fab may contain a VH-VL crossover to reduce light chain mispairing and side products. The amino acid substitution "RK / EE" can be introduced into CL-CH1 to reduce light chain mispairing / side products during manufacturing. The CD3 Fab and BCMA Fab may be linked to each other with a flexible linker. [Figure 3]Figure 3 shows different formats of bispecific trivalent antibodies for use in the present invention, which contain Fab fragments that bind to CD3 and BCMA in the following formats: Fc-Fab CD3-Fab BCMA (A, B); Fc-Fab BCMA-Fab CD3 (C, D). The CD3 Fab may contain a VH-VL crossover to reduce light chain mispairing and side products. The amino acid substitution "RK / EE" can be introduced into CL-CH1 to reduce light chain mispairing / side products during manufacturing. The CD3 Fab and BCMA Fab may be linked to each other with a flexible linker. [Figure 4] FIG. 4 shows cytokine release syndrome events for all subjects in the clinical trial of CC-93269 in relapsed / refractory multiple myeloma (RRMM) of Examples 1 and 2. [Figure 5] FIG. 5 shows the frequency of cytokine release syndrome events across all subjects in the clinical trial of CC-93269 in relapsed / refractory multiple myeloma (RRMM) of Examples 1 and 2. [Figure 6] Figure 6 shows the effect of dexamethasone on CC-93269-induced cytokine secretion as described in Example 3. Cytokines (pg / mL) are graphed as the mean ± standard deviation of triplicate samples. H929, MM1S, KMS1, and SKMM2 are BCMA-expressing myeloma cell lines. Dex = dexamethasone. [Figure 7] Figure 7 shows the effect of dexamethasone on CC-93269-induced cytolysis of BCMA-expressing myeloma cell lines (H929, MM.1S, KMS12-PE, and SKMM2) described in Example 3. The percentage of viable tumor cells is graphed as the mean ± standard deviation of triplicate samples. Dex = dexamethasone. [Figure 8]Figure 8 shows the effect of dexamethasone on CC-93269-induced T cell proliferation and activation, as described in Example 3. Proliferation is measured as the percentage of CD4+ / CD8+ T cells exhibiting CellTrace Violet dilution after co-culture with tumor cell lines compared to cultures of T cells alone. Expression of activation markers CD25, CD69, and HLA-DR on CD4+ and CD8+ T cells is measured as the percentage of CD4+ / CD8+ T cells expressing the activation marker after co-culture with tumor cell lines compared to cultures of T cells alone. Both proliferation and activation marker expression are graphed as the mean ± standard deviation of triplicate samples. SKMM2 is a BCMA-expressing myeloma cell line. Dex = dexamethasone. DETAILED DESCRIPTION OF THE INVENTION

[0035] Detailed Description As used herein, the articles "a" and "an" can refer to one or to more than one (e.g., to at least one) of the grammatical object of the article.

[0036] "About" can generally refer to an acceptable degree of error for a measured quantity given the nature or precision of the measurement. Exemplary degrees of error are within 20 percent (%), typically within 10%, and more typically within 5% of a given value or range of values.

[0037] An embodiment described herein as "comprising" one or more features may also be considered a disclosure of the corresponding embodiment that "consists of" and / or "consists essentially of" such features.

[0038] Concentrations, amounts, volumes, percentages, and other numerical values ​​may be presented herein in a range format, with it being understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values ​​explicitly recited as range limitations, but also all individual numerical values ​​or subranges subsumed within that range as if each numerical value and subrange were explicitly recited.

[0039] Treatment method The present invention is based, in part, on a method of treating patients with disorders associated with BCMA expression (e.g., B-cell cancers such as multiple myeloma) using a dose-escalating administration regimen with a multispecific (e.g., bispecific) antibody that binds to CD3 and BCMA. The method is expected to reduce or suppress undesirable treatment effects, such as cytokine release syndrome (CRS), thereby treating patients while achieving a more favorable benefit-risk profile. In certain embodiments, the "subject" or "patient" is a human.

[0040] As used herein, a "disorder associated with BCMA expression" is a plasma cell or B cell disorder that correlates with increased BCMA expression. Plasma cell disorders include BCMA-expressing B cell cancers, plasmacytomas, plasma cell leukemias, multiple myeloma, macroglobulinemias, amyloidoses, Waldenstrom's macroglobulinemia, isolated bone plasmacytoma, extramedullary plasmacytomas, osteosclerosing myeloma (POEMS syndrome), and heavy chain disease, as well as clinically indeterminate monoclonal gammopathy / smoldering multiple myeloma.

[0041] In some embodiments, the B cell disorder is a BCMA-expressing B cell cancer, such as multiple myeloma. Multiple myeloma is a plasma cell malignancy characterized by monoclonal expansion and accumulation of abnormal plasma cells within the bone marrow compartment. Multiple myeloma also involves circulating clonal plasma cells with the same IgG gene rearrangements and somatic hypermutations. Multiple myeloma arises from an asymptomatic precancerous condition called monoclonal gammopathy of undetermined significance (MGUS), which is characterized by low levels of bone marrow plasma cells and monoclonal proteins. Multiple myeloma cells proliferate slowly. Multiple myeloma results from the progressive development of multiple structural chromosomal alterations (e.g., unbalanced translocations). Multiple myeloma involves alternating interactions between malignant plasma cells and the bone marrow microenvironment (e.g., normal bone marrow stromal cells). Clinical signs of active multiple myeloma include monoclonal antibody spikes, plasma cell-overcrowded bone marrow, lytic bone lesions, and bone destruction due to overstimulation of osteoclasts (Dimopulos & Terpos, Ann Oncol 2010; 21 suppl 7: vii143-150).

[0042] As used herein, the terms "treat," "treatment," and the like refer to obtaining a desired pharmacological and / or physiological effect. Preferably, the effect is therapeutic, i.e., the effect partially or completely cures the disease and / or adverse symptoms resulting from the disease. Alternatively, the pharmacological and / or physiological effect may be prophylactic, i.e., the effect completely or partially prevents the disease or its symptoms.

[0043] Accordingly, in one aspect, the invention provides a method of treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises: (i) an initiation phase in which one or more initial doses of a multispecific (e.g., bispecific) antibody are administered to the patient; and (ii) a maintenance phase, in which an initial maintenance dose of a multispecific (e.g., bispecific) antibody is administered to the patient, optionally followed by at least one additional maintenance dose of the multispecific (e.g., bispecific) antibody; wherein each maintenance dose is greater than one or more starting doses; The dosing regimen includes administration of a multispecific (e.g., bispecific) antibody that binds to BCMA and CD3.

[0044] In another aspect, the present invention provides a multispecific (e.g., bispecific) antibody that binds BCMA and CD3 for use in treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises administration of the multispecific (e.g., bispecific) antibody in a dosing regimen comprising: (i) an initiation phase in which one or more initial doses of a multispecific (e.g., bispecific) antibody are administered to the patient; and (ii) a maintenance phase, in which an initial maintenance dose of a multispecific (e.g., bispecific) antibody is administered to the patient, optionally followed by at least one additional maintenance dose of the multispecific (e.g., bispecific) antibody; wherein each maintenance dose is greater than one or more of the starting doses.

[0045] Administration of a starting dose of a multispecific (eg, bispecific) antibody significantly reduces toxicity due to reduced cytokine release.

[0046] In some embodiments, the starting phase comprises a single fixed dose. In some embodiments, the starting dose of a multispecific (e.g., bispecific) antibody is a single fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, or about 2.5 mg to 3.5 mg, e.g., about 3 mg. In some embodiments, the starting dose of a multispecific (e.g., bispecific) antibody is a single fixed dose of about 4.5 mg to 7.5 mg, about 5 mg to 6 mg, or about 5.5 mg to 6.5 mg, e.g., about 6 mg.

[0047] In other embodiments, the starting phase comprises two or more starting doses of the same concentration. In embodiments in which the starting doses are administered as two or more doses of the same concentration, the starting dose of the multispecific (e.g., bispecific) antibody can be administered as a fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, about 2.5 mg to 3.5 mg, e.g., about 3 mg. Alternatively, the starting dose of the multispecific (e.g., bispecific) antibody can be administered as a fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, about 2.5 mg to 3.5 mg, e.g., about 6 mg.

[0048] If a patient develops an adverse event (e.g., CRS or infection) after administration of a starting dose (e.g., a first starting dose) of a multispecific (e.g., bispecific) antibody, a subsequent starting dose (e.g., a second starting dose) can be administered to the patient up to 12 weeks after the starting dose that induced the adverse event. In some embodiments, the subsequent starting dose can be administered up to 10 weeks, up to 8 weeks, up to 6 weeks, up to 4 weeks, up to 2 weeks, e.g., up to 1 week after the starting dose that induced the adverse event. In some embodiments, the subsequent starting dose can be at the same concentration as or a lower concentration than the starting dose that induced the adverse event.

[0049] If a patient develops an adverse event (e.g., CRS or infection) after administration of the final starting dose of the initiation phase, the initiation phase may include an additional starting dose administered to the patient up to 12 weeks after the starting dose that induced the adverse event. In some embodiments, the additional starting dose may be administered up to 10 weeks, up to 8 weeks, up to 6 weeks, up to 4 weeks, up to 2 weeks, e.g., up to 1 week after the starting dose that induced the adverse event. In some embodiments, the additional starting dose may be at the same concentration as or a lower concentration than the starting dose that induced the adverse event.

[0050] In some embodiments, the initial maintenance dose of the multispecific (e.g., bispecific) antibody can be administered at a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; about 5.5 mg to 6.5 mg, e.g., about 6 mg. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, and the initial maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg.

[0051] In some embodiments, the initial maintenance dose of the multispecific (e.g., bispecific) antibody can be administered as a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 6 mg, and the initial maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 10 mg.

[0052] In some embodiments, the maintenance phase includes two or more maintenance doses at the same concentration or at increasing concentrations.

[0053] In some embodiments, the maintenance phase includes two or more maintenance doses of about 4.5 mg to about 25 mg, preferably about 4.5 mg to about 11.5 mg. In some embodiments, the maintenance phase includes two or more maintenance doses of about 4.5 mg to about 7.5 mg; about 5 mg to about 6 mg; or about 5.5 mg to about 6.5 mg, for example, about 6 mg. In some embodiments, the maintenance phase includes two or more maintenance doses of about 8.5 mg to about 11.5 mg; about 9 mg to about 11 mg; or about 9.5 mg to about 10.5 mg, for example, about 10 mg. In some embodiments, the maintenance phase includes two or more maintenance doses of about 6 mg to about 11.5 mg, about 6.5 mg to about 11 mg, or about 7 mg to about 10.5 mg, for example, about 7.5 mg to about 10 mg, for example, about 10 mg. In some embodiments, the maintenance phase includes two or more maintenance doses of about 18.5 mg to 21.5 mg; about 19 mg to 21 mg; about 19.5 mg to 20.5 mg, for example, about 20 mg.

[0054] In embodiments where the maintenance dose is administered as two or more doses of the same concentration, the maintenance dose of the multispecific (e.g., bispecific) antibody can be administered at a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; about 5.5 mg to 6.5 mg, e.g., about 6 mg. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, and the maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg.

[0055] In embodiments where the maintenance dose is administered as two or more doses of the same concentration, the maintenance dose of the multispecific (e.g., bispecific) antibody can be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 6 mg, and the maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 10 mg.

[0056] In certain embodiments, a maintenance dose of a multispecific (e.g., bispecific) antibody is administered as two or more doses of increasing concentration (i.e., increasing doses). In this case, subsequent doses can be increased by specific or variable increments until a maximum dose is reached, at which point administration can be stopped or continued at the maximum dose. Thus, in embodiments in which maintenance doses are administered at increasing concentrations, the first maintenance dose of the multispecific (e.g., bispecific) antibody is greater than the starting dose, and subsequent (e.g., second, third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody are greater than the first maintenance dose. For example, the first maintenance dose of the multispecific (e.g., bispecific) antibody is greater than the starting dose, the second maintenance dose(s) of the multispecific (e.g., bispecific) antibody is the same as the first maintenance dose, and the third (and optionally subsequent) maintenance dose(s) of the multispecific (e.g., bispecific) antibody are greater than the second maintenance dose.

[0057] In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; about 5.5 mg to 6.5 mg, e.g., about 6 mg, and subsequent (e.g., second, third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg.

[0058] In certain embodiments, the initial maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg, and subsequent (e.g., second, third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be administered at fixed doses that are higher than the initial maintenance dose.

[0059] In some embodiments, the second maintenance dose of the multispecific (e.g., bispecific) antibody is larger than the initial maintenance dose. In some embodiments, the initial maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 4.5 mg to about 7.5 mg; about 5 mg to about 6 mg; or about 5.5 mg to about 6.5 mg, e.g., about 6 mg, and the second maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; or about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose is a (e.g., single) fixed dose of about 3 mg, the first maintenance dose is a fixed dose of about 6 mg, and the second maintenance dose is a fixed dose of about 10 mg. In some embodiments, subsequent (e.g., third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be the same or larger than the second maintenance dose.

[0060] In some embodiments, the initial maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg, and the second maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose larger than the initial maintenance dose. Thus, in some embodiments, the starting dose is a (e.g., single) fixed dose of about 6 mg, the initial maintenance dose is a fixed dose of about 10 mg, and the second maintenance dose is a larger fixed dose than the initial maintenance dose. In some embodiments, subsequent (e.g., third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be the same or larger than the second maintenance dose.

[0061] In some embodiments, the maintenance dose of a multispecific (e.g., bispecific) antibody is administered at two concentrations: an initial concentration and a maximum dose concentration. In some embodiments, the initial maintenance dose may be administered at a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 7 mg; or about 5.5 mg to 6.5 mg, e.g., about 6 mg, and a subsequent (e.g., second) maintenance dose of the multispecific antibody may be administered at the maximum dose concentration. In some embodiments, the maximum dose concentration is a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; or about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in some embodiments, the starting dose is a (e.g., single) fixed dose of about 3 mg, the first maintenance dose is a fixed dose of about 6 mg, and the subsequent (e.g., second) maintenance dose is a maximum dose, which is a fixed dose of about 10 mg. When the maximum maintenance dose is administered subcutaneously, the maximum dose concentration may be about 18.5 mg to 21.5 mg; about 19 mg to 21 mg; about 19.5 mg to 20.5 mg, for example, a fixed dose of about 20 mg.

[0062] In some embodiments, the first maintenance dose may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg, and a subsequent (e.g., second) maintenance dose of the multispecific (e.g., bispecific) antibody may be administered at a maximum dose level. Thus, in some embodiments, the starting dose is a (e.g., single) fixed dose of about 6 mg, the first maintenance dose is a fixed dose of about 10 mg, and the subsequent (e.g., second) maintenance dose is a maximum dose that is greater than the first maintenance dose.

[0063] In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 1-21 days after the initial dose, e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, or 14 days after the initial dose. In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered to the patient 2 days after the initial dose. In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered to the patient 3 days after the initial dose. In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered to the patient 7 days after the initial dose. In some embodiments, the first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered to the patient 14 days after the initial dose.

[0064] In some embodiments, the second maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 1-21 days, e.g., 2 days, 4 days, 7 days, or 14 days, after the first maintenance dose. Thus, in embodiments in which the first maintenance dose is administered 2 days after the starting dose, the second maintenance dose may be administered 2 days after the first maintenance dose, and, optionally, the third maintenance dose may be administered 3 days after the second maintenance dose.

[0065] In embodiments where the first maintenance dose is administered 3 days after the initial dose, the second maintenance dose may be administered 4 days after the first maintenance dose. In embodiments where the first maintenance dose is administered 7 days after the initial dose, the second (and optionally subsequent) maintenance dose may be administered 7 days after the first maintenance dose. In embodiments where the first maintenance dose is administered 14 days after the initial dose, the second (and optionally subsequent) maintenance dose may be administered 14 days after the first maintenance dose.

[0066] In certain embodiments of any aspect of the invention, if a patient develops an adverse event (e.g., CRS or infection) after administration of a maintenance dose (e.g., a first, second, third, or subsequent maintenance dose) of a multispecific (e.g., bispecific) antibody, the next maintenance dose may be administered to the patient up to 12 weeks after the maintenance dose that induced the adverse event. In certain embodiments, the next maintenance dose may be administered up to 10 weeks, up to 8 weeks, up to 6 weeks, up to 4 weeks, up to 2 weeks, e.g., up to 1 week after the maintenance dose that induced the adverse event. In certain embodiments, the next maintenance dose may be at the same concentration as or a lower concentration than the maintenance dose that induced the adverse event.

[0067] In certain embodiments of any aspect of the invention, the third and subsequent maintenance doses are administered at a dosing interval of about one or more weeks. As used herein, a "dosing interval" refers to the time that elapses between doses administered to a patient. If an adverse event (e.g., CRS or infection) occurs after administration of a maintenance dose (e.g., a third or subsequent maintenance dose) of a multispecific (e.g., bispecific) antibody, the dosing interval can be reset to the day the next maintenance dose is administered to the patient.

[0068] In certain embodiments of any aspect of the invention, the administration interval between the third and subsequent maintenance doses may be about once per week. As used herein, a "weekly administration interval" includes every 5-9 days, every 6-9 days, every 7-9 days, every 5-8 days, every 5-7 days, every 6-8 days, every 6-7 days, every 7-8 days, and preferably every 7 days. In certain embodiments, the administration interval between the third and subsequent maintenance doses may be about once per two weeks. As used herein, a "biweekly administration interval" includes every 12-16 days, every 13-16 days, every 14-16 days, every 12-15 days, every 12-14 days, every 13-15 days, every 13-14 days, every 14-15 days, and preferably every 14 days. In certain embodiments, the administration interval between the third and subsequent maintenance doses may be about once per three weeks. As used herein, "a dosing interval every three weeks" includes every 19-23 days, every 20-23 days, every 21-23 days, every 19-22 days, every 19-21 days, every 20-22 days, every 20-21 days, every 21-22 days, preferably every 21 days. In some embodiments, the dosing interval between the third and subsequent maintenance doses may be about once every four weeks. As used herein, "a dosing interval every four weeks" includes every 26-30 days, every 27-30 days, every 28-30 days, every 26-29 days, every 26-28 days, every 27-29 days, every 27-28 days, every 28-29 days, preferably every 28 days. In some embodiments, the dosing interval between the third and subsequent maintenance doses may be about once a month.

[0069] In certain embodiments of any aspect of the invention, the dosing interval for the third and subsequent maintenance doses can be a combination of one or more of a weekly dosing interval, a biweekly dosing interval, a three-weekly dosing interval, and a four-weekly dosing interval, hi some embodiments, the dosing interval for the third and subsequent maintenance doses can be a combination of a weekly dosing interval, a biweekly dosing interval, and a four-weekly dosing interval.

[0070] In certain embodiments of any aspect of the invention, the third and subsequent maintenance doses are administered at weekly dosing intervals (e.g., every 7 days), then biweekly dosing intervals (e.g., every 14 days), then triweekly dosing intervals (e.g., every 21 days), then fourweekly dosing intervals (e.g., every 28 days). In certain embodiments, the third and subsequent maintenance doses are administered at weekly dosing intervals (e.g., every 7 days), then biweekly dosing intervals (e.g., every 14 days), then fourweekly dosing intervals (e.g., every 28 days).

[0071] In certain embodiments of any aspect of the invention, the treatment comprises at least one treatment cycle of 28 days. As used herein, a "treatment cycle" is 28 days. When an initial dose is administered beyond day 28 of the initial treatment cycle as a result of an adverse event (e.g., CRS or infection), the initial treatment cycle may be resumed on the day the initial dose was administered to the patient. When a maintenance dose is administered beyond day 28 of the current treatment cycle as a result of an adverse event (e.g., CRS or infection), the next treatment cycle may begin on the day the maintenance dose was administered to the patient. In certain embodiments, the treatment comprises a first treatment cycle in which an initial dose is administered to the patient as a fixed dose on day 1, followed by maintenance doses administered at weekly dosing intervals (e.g., every 7 days) for three consecutive weeks (e.g., on days 8, 15, and 22). The maintenance dose may continue to be administered at one or more weekly dosing intervals in subsequent treatment cycles.

[0072] In certain embodiments of any aspect of the invention, the treatment includes a second treatment cycle, wherein the maintenance doses are administered at a once-weekly dosing interval (e.g., on days 1, 8, 15, and 22). In further embodiments, the patient maintains the once-weekly dosing interval for 1-5 treatment cycles, for 1-3 treatment cycles, for 1-2 treatment cycles, for 2-3 treatment cycles, preferably for two additional treatment cycles (in addition to the first treatment cycle). In certain embodiments, the treatment includes a second and a third treatment cycle, wherein the maintenance doses are administered at a once-weekly dosing interval (e.g., on days 1, 8, 15, and 22).

[0073] In certain embodiments of any aspect of the invention, a maintenance dose may be administered at a biweekly dosing interval (e.g., on days 1 and 15) of a treatment cycle after completion of a weekly treatment cycle(s). In further embodiments, the patient maintains a biweekly dosing interval for 1-5 cycles, 1-3 cycles, 1-2 cycles, 2-3 cycles of biweekly treatment cycles, preferably for a 3-weekly treatment cycle. In some embodiments, the treatment includes a fourth, fifth, and sixth treatment cycle, wherein the maintenance dose is administered at a biweekly dosing interval (e.g., on days 1 and 15).

[0074] In certain embodiments of any aspect of the invention, maintenance doses may be administered at 3-week dosing intervals in subsequent treatment cycles (e.g., the subsequent cycles are (a), (b), and (c) in the order (a), (b), and (c), where the maintenance doses are administered on days 1 and 22 of cycle (a), day 15 of cycle (b), and day 8 of cycle (c)) after completion of the once-every-2-week treatment cycle(s). In further embodiments, the patient maintains the 3-week dosing interval for one, two, or three treatment cycles.

[0075] In certain embodiments of any aspect of the invention, the maintenance dose may be administered at a 4-week dosing interval (e.g., on day 1) in the subsequent treatment cycle after completion of the biweekly treatment cycle(s). In another embodiment, the maintenance dose may be administered at a 4-week dosing interval (e.g., on day 1) in the subsequent treatment cycle after completion of the 3-week treatment cycle(s). In a further embodiment, the patient maintains the 4-week dosing interval for at least one cycle. Some patients continue to receive treatment for the rest of their lives.

[0076] In some embodiments, the treatment includes: (i) an initial treatment cycle in which the starting dose is administered on day 1 and maintenance doses are administered on days 8, 15, and 22; (ii) a second and third treatment cycle in which the maintenance dose is administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22); (iii) treatment cycles 4 through 6, in which the maintenance dose is administered at biweekly dosing intervals (e.g., on days 1 and 15); and (iv) The seventh and subsequent cycles, in which a maintenance dose is administered at a 4-week dosing interval (e.g., on Day 1).

[0077] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 1.

[0078] [Table 1]

[0079] In another embodiment, the treatment comprises an initial treatment cycle, in which an initial dose is administered to the patient as a fixed dose on day 1, a first maintenance dose is administered three days (e.g., day 4) after the initial dose, a second maintenance dose is administered four days (e.g., day 8) after the first maintenance dose, and a third and fourth maintenance doses are administered at weekly intervals (e.g., on days 15 and 22). The maintenance doses may continue to be administered at weekly or longer dosing intervals in subsequent treatment cycles.

[0080] In some embodiments of any aspect of the invention, the treatment includes a second treatment cycle, wherein the maintenance doses are administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22). In further embodiments, the patient maintains the weekly dosing interval for 1-5 cycles, 1-3 cycles, 1-2 cycles, or 2-3 additional treatment cycles, preferably for two additional treatment cycles (in addition to the first treatment cycle). In some embodiments, the treatment includes a second and a third treatment cycle, wherein the maintenance doses are administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22).

[0081] In certain embodiments of any aspect of the invention, a maintenance dose may be administered at a biweekly dosing interval (e.g., on days 1 and 15) of a treatment cycle after completion of a weekly treatment cycle(s). In further embodiments, the patient is administered at a biweekly dosing interval for 1-5, 1-3, 1-2, 2-3 weekly treatment cycles, preferably maintaining 3 biweekly treatment cycles. In some embodiments, the treatment includes a fourth, fifth, and sixth treatment cycle, wherein the maintenance dose is administered at a biweekly dosing interval (e.g., on days 1 and 15).

[0082] In certain embodiments of any aspect of the invention, a maintenance dose may be administered at a 4-week dosing interval (e.g., on day 1) in a subsequent treatment cycle after completion of a biweekly treatment cycle(s). In further embodiments, the patient maintains the 4-week dosing interval for at least one cycle. Some patients continue to receive treatment for the rest of their lives.

[0083] In some embodiments, the treatment includes: (i) an initial treatment cycle in which the starting dose is administered on day 1 and maintenance doses are administered on days 4, 8, 15, and 22; (ii) a second and third treatment cycle in which the maintenance dose is administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22); (iii) treatment cycles 4 through 6, in which the maintenance dose is administered at biweekly dosing intervals (e.g., on days 1 and 15); and (iv) The seventh and subsequent cycles, in which a maintenance dose is administered at a 4-week dosing interval (e.g., on Day 1).

[0084] In some embodiments, a multispecific (eg, bispecific) antibody (eg, "42-TCBcv") can be administered to a patient according to the regimen shown in Table 2.

[0085] [Table 2]

[0086] In another embodiment, the treatment comprises an initial treatment cycle, in which an initial dose is administered to the patient as a fixed dose on day 1, a first maintenance dose is administered two days (e.g., day 3) after the initial dose, a second maintenance dose is administered two days (e.g., day 5) after the first maintenance dose, a third maintenance dose is administered three days (e.g., day 8) after the first maintenance dose, and a fourth and fifth maintenance doses are administered at weekly intervals (e.g., days 15 and 22). The maintenance doses may continue to be administered at one or more weekly dosing intervals in subsequent treatment cycles.

[0087] In some embodiments of any aspect of the invention, the treatment includes a second treatment cycle, wherein the maintenance doses are administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22). In further embodiments, the patient maintains the weekly dosing interval for between 1-5, 1-3, 1-2, 2-3 additional treatment cycles, preferably two additional treatment cycles (in addition to the first treatment cycle). In some embodiments, the treatment includes a second and third treatment cycle, wherein the maintenance doses are administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22).

[0088] In certain embodiments of any aspect of the invention, a maintenance dose may be administered at a biweekly dosing interval (e.g., on days 1 and 15) of a treatment cycle after completion of a weekly treatment cycle(s). In further embodiments, the patient maintains a biweekly dosing interval for 1-5, 1-3, 1-2, 2-3 cycles of weekly treatment cycles, preferably 3 cycles of biweekly treatment cycles. In some embodiments, the treatment includes a fourth, fifth, and sixth treatment cycle, in which a maintenance dose is administered at a biweekly dosing interval (e.g., on days 1 and 15).

[0089] In certain embodiments of any aspect of the invention, a maintenance dose may be administered at a 4-week dosing interval in a subsequent treatment cycle (e.g., on Day 1) after completion of a biweekly treatment cycle(s). In further embodiments, the patient maintains the 4-week dosing interval for at least one cycle. Some patients continue to receive treatment for the rest of their lives.

[0090] In some embodiments, the treatment includes: (i) an initial treatment cycle in which the starting dose is administered on day 1 and maintenance doses are administered on days 3, 5, 8, 15, and 22; (ii) a second and third treatment cycle in which the maintenance dose is administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22); (iii) treatment cycles 4 through 6, in which the maintenance dose is administered at biweekly dosing intervals (e.g., on days 1 and 15); and (iv) The seventh and subsequent cycles, in which a maintenance dose is administered at a 4-week dosing interval (e.g., on Day 1).

[0091] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 3.

[0092] [Table 3]

[0093] In some embodiments of the regimens shown in Table 1, Table 2, or Table 3, the maintenance dose of the multispecific (e.g., bispecific) antibody is administered as two or more doses of the same concentration. In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 1.5 mg to 4.5 mg; about 2 mg to 4 mg; about 2.5 mg to 3.5 mg, e.g., about 3 mg. In some embodiments, the initial and subsequent maintenance doses of the multispecific (e.g., bispecific) antibody are fixed doses of about 4.5 mg to 7.5 mg; about 5 mg to 7 mg; or about 5.5 mg to 6.5 mg, e.g., about 6 mg. In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, and the initial and subsequent maintenance doses of the multispecific (e.g., bispecific) antibody are fixed doses of about 6 mg.

[0094] In some embodiments of the regimens shown in Table 1, Table 2, or Table 3, the maintenance dose of the multispecific (e.g., bispecific) antibody is administered as two or more doses of the same concentration. In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 6 mg; or about 5.5 mg to 6.5 mg, e.g., about 6 mg. In some embodiments, the initial and subsequent maintenance doses of the multispecific (e.g., bispecific) antibody are fixed doses of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; or about 9.5 mg to 10.5 mg, e.g., about 10 mg. In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg, and the initial and subsequent maintenance doses of the multispecific (e.g., bispecific) antibody are fixed doses of about 10 mg.

[0095] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 4.

[0096] [Table 4]

[0097] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 5.

[0098] [Table 5]

[0099] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 6.

[0100] [Table 6]

[0101] In certain embodiments of the regimens shown in Table 1, Table 2, or Table 3, the maintenance dose of the multispecific (e.g., bispecific) antibody is administered as two or more doses of increasing concentrations.

[0102] In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 1.5 mg to 4.5 mg, about 2 mg to 4 mg, or about 2.5 mg to 3.5 mg, e.g., about 3 mg. In some embodiments, the first maintenance dose may be administered at a fixed dose of about 4.5 mg to about 7.5 mg, about 5 mg to about 7 mg, or about 5.5 mg to about 6.5 mg, e.g., about 6 mg, and the second (and optionally subsequent) maintenance dose(s) of the multispecific (e.g., bispecific) antibody may be administered at a fixed dose of about 8.5 mg to 11.5 mg, about 9 mg to 11 mg, or about 9.5 mg to 10.5 mg, e.g., about 10 mg. Thus, in one embodiment, the starting dose of the multispecific (e.g., bispecific) antibody is a (e.g., single) fixed dose of about 3 mg, the first maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg, and the second (and optionally subsequent) maintenance dose(s) of the multispecific (e.g., bispecific) antibody is a fixed dose of about 10 mg.

[0103] In some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 4.5 mg to 7.5 mg; about 5 mg to 7 mg; about 5.5 mg to 6.5 mg, e.g., about 6 mg. In some embodiments, the first maintenance dose may be administered at a fixed dose of about 8.5 mg to 11.5 mg; about 9 mg to 11 mg; about 9.5 mg to 10.5 mg, e.g., about 10 mg, and the second (and optionally subsequent) maintenance dose(s) of the multispecific (e.g., bispecific) antibody may be administered at a higher fixed dose than the first maintenance dose. Thus, in some embodiments, the starting dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 6 mg, the first maintenance dose of the multispecific (e.g., bispecific) antibody is a fixed dose of about 10 mg, and the second (and optionally subsequent) maintenance dose(s) of the multispecific (e.g., bispecific) antibody is higher than the first maintenance dose.

[0104] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 7.

[0105] [Table 7]

[0106] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 8.

[0107] [Table 8]

[0108] In some embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen shown in Table 9.

[0109] [Table 9]

[0110] In certain embodiments of any aspect of the invention, multispecific (e.g., bispecific) antibodies are administered intravenously or subcutaneously. In this regard, data (not shown) suggest that subcutaneous administration of multispecific (e.g., bispecific) antibodies (e.g., 42-TCBcv) has bioavailability comparable to intravenous administration.

[0111] In some embodiments, the starting dose and first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered intravenously, and subsequent (e.g., second, third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be administered subcutaneously.

[0112] In certain embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") may be administered to a patient according to any of the regimens set forth in Tables 1-9, wherein the starting dose and first maintenance dose of the multispecific (e.g., bispecific) antibody may be administered intravenously, and the subsequent (e.g., second, third, fourth, or fifth) maintenance doses of the multispecific (e.g., bispecific) antibody may be administered subcutaneously.

[0113] In certain embodiments, a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") may be administered to a patient according to any of the regimens shown in Tables 1-9, where cycles 1-2 may be administered intravenously and cycles 3+ may be administered subcutaneously.

[0114] When a dose of a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") is administered subcutaneously, the maximum dose concentration may be about 18.5 mg to 21.5 mg; about 19 mg to 21 mg; about 19.5 mg to 20.5 mg, for example, a fixed dose of about 20 mg.

[0115] In a preferred embodiment of any aspect of the invention, multispecific (e.g., bispecific) antibodies are administered intravenously.

[0116] High-dose administration of multispecific (e.g., bispecific) antibodies In another aspect, the invention provides a method of treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises administering to the patient an initial maintenance dose of a multispecific (e.g., bispecific) antibody that binds BCMA and CD3, followed by, optionally, one or more additional maintenance doses of the multispecific (e.g., bispecific) antibody.

[0117] In another aspect, the present invention provides multispecific (e.g., bispecific) antibodies that bind BCMA and CD3 for use in treating a disorder associated with BCMA expression (e.g., a BCMA-expressing B-cell cancer such as multiple myeloma) in a patient (e.g., a human), wherein the treatment comprises administration to the patient of an initial maintenance dose of the multispecific (e.g., bispecific) antibody, optionally followed by one or more additional maintenance doses (multiple times) of the multispecific (e.g., bispecific) antibody.

[0118] In certain embodiments, the initial maintenance dose may have a concentration of about 4.5 mg to about 11.5 mg (herein referred to as a "high dose of a multispecific (e.g., bispecific) antibody"). In certain embodiments, the initial maintenance dose is a fixed dose of 6 mg or more, 6.5 mg or more, 7 mg or more, for example, 7.5 mg or more. In certain embodiments, the initial maintenance dose is a fixed dose of about 6 mg to about 11.5 mg, about 6.5 mg to about 11 mg, about 7 mg to about 10.5 mg, for example, about 7.5 mg to about 10 mg. In certain embodiments, the initial maintenance dose is a fixed dose of about 8.5 mg to about 11.5 mg; about 9 mg to about 11 mg; or about 9.5 mg to about 10.5 mg, for example, about 10 mg. In other embodiments, the initial maintenance dose is a fixed dose of about 4.5 mg to about 7.5 mg; about 5 mg to about 6 mg; or about 5.5 mg to about 6.5 mg, for example, about 6 mg.

[0119] In certain embodiments, after administration of the first maintenance dose, no CRS events of grade >3 occur, preferably no CRS events of grade >2 occur, preferably no CRS events of grade >1 occur, preferably no CRS events of grade 1 or higher occur, and optionally, the first maintenance dose is administered without prophylactic administration of dexamethasone.

[0120] In embodiments where the treatment includes one or more additional maintenance dose(s), i.e., at least a second maintenance dose, of the multispecific (e.g., bispecific) antibody, the second maintenance dose may be administered to the patient 1-21 days after the first maintenance dose, e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, or 21 days after. In some embodiments, the second maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 7 days after the first maintenance dose. In some embodiments, the second maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 14 days after the first maintenance dose. In certain embodiments, after administration of the second maintenance dose, no CRS events of grade >3 occur, preferably no CRS events of grade >2 occur, preferably no CRS events of grade >1 occur, preferably no CRS events of grade 1 or higher occur, preferably no CRS events occur, and optionally the second maintenance dose is administered without prophylactic administration of dexamethasone.

[0121] The treatment may include a third maintenance dose of the multispecific (e.g., bispecific) antibody administered to the patient 1-21 days after the second maintenance dose, e.g., 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, or 21 days after. In some embodiments, the third maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 7 days after the second maintenance dose. In some embodiments, the third maintenance dose of the multispecific (e.g., bispecific) antibody is administered to the patient 14 days after the second maintenance dose. In certain embodiments, after administration of the third maintenance dose, no CRS events of grade >3 occur, preferably no CRS events of grade >2 occur, preferably no CRS events of grade >1 occur, preferably no CRS events of grade 1 or higher occur, and optionally, the third maintenance dose is administered without prophylactic administration of dexamethasone.

[0122] In some embodiments, the treatment includes administering additional maintenance doses, e.g., a fourth, fifth, sixth, etc. In some embodiments in which the treatment includes a fourth maintenance dose, the treatment comprises an initial treatment cycle, optionally in which the initial maintenance dose is administered to the patient as a fixed dose on day 1, followed by additional maintenance doses administered at weekly dosing intervals (e.g., every seven days) for three consecutive weeks (e.g., on days 8, 15, and 22).

[0123] In some embodiments, the treatment includes subsequent treatment cycles, e.g., a second, third, fourth, fifth, sixth, seventh treatment cycle. In some embodiments, the treatment includes subsequent treatment cycles, the maintenance dose continues to be administered at one or more weekly dosing intervals in the subsequent treatment cycles.

[0124] In some embodiments, the treatment includes: (i) an initial treatment cycle in which the first maintenance dose is administered on day 1, and additional maintenance doses are administered on days 8, 15, and 22; (ii) a second and third treatment cycle in which the maintenance dose is administered at weekly dosing intervals (e.g., on days 1, 8, 15, and 22); (iii) a fourth and fifth treatment cycle in which the maintenance dose is administered at biweekly dosing intervals (e.g., on days 1 and 15); and (iv) Cycles 7 and thereafter, in which the maintenance dose is administered at a 4-week dosing interval (e.g., on Day 1).

[0125] Thus, it is understood that a multispecific (e.g., bispecific) antibody (e.g., "42-TCBcv") can be administered to a patient according to the regimen set forth in Table 1, in which an initial maintenance dose is administered in place of a "starting dose."

[0126] In some embodiments, the one or more additional maintenance dose(s) are fixed doses of the same concentration as the initial maintenance dose. If a patient experiences an adverse event (e.g., CRS) after administration of a maintenance dose (e.g., the first, second, third, or fourth maintenance dose), the subsequent maintenance dose (e.g., the second, third, fourth, or fifth maintenance dose) can be at a lower concentration than the maintenance dose that induced the adverse event (e.g., CRS).

[0127] Adverse events In certain embodiments of any aspect of the invention, the patient experiences or is at risk of experiencing an adverse event associated with administration of the multispecific (e.g., bispecific) antibody. The adverse event can be cytokine-induced toxicity (e.g., cytokine release syndrome (CRS)), infusion-related reaction (IRR), macrophage activation syndrome (MAS), neurotoxicity, severe tumor lysis syndrome (TLS), neutropenia, thrombocytopenia, elevated liver enzymes, bacterial infection, viral infection, and / or central nervous system (CNS) toxicity. In certain embodiments, the adverse event is CRS.

[0128] If a patient experiences or is at risk of experiencing an adverse event associated with administration of a multispecific (e.g., bispecific) antibody, treatment according to any aspect of the invention can further include administration of an agent capable of treating, preventing, delaying, ameliorating, or reducing the onset or risk of onset of the adverse event. The agent can be administered to the patient prior to initiation of treatment with the multispecific (e.g., bispecific) antibody (e.g., as prophylaxis to prevent or reduce the risk of experiencing an adverse event) or during treatment with the multispecific (e.g., bispecific) antibody (e.g., in response to the onset of an adverse event). In some embodiments, the agent comprises a steroid, e.g., a corticosteroid. As used herein, "corticosteroid" refers to any natural or synthetic steroid hormone that can be derived from cholesterol and is characterized by a hydrogenated cyclopentanoperhydrophenanthrene ring system. Natural corticosteroids are generally produced by the adrenal cortex. Synthetic corticosteroids may be halogenated. Functional groups required for activity include a Δ4 double bond, a C3 ketone, and a C20 ketone. The corticosteroid may have glucocorticoid and / or mineralocorticoid activity. Exemplary corticosteroids include prednisolone, methylprednisolone, prednisone, triamcinolone, betamethasone, budesonide and dexamethasone. In some embodiments, the drug is dexamethasone.

[0129] In some embodiments, the agent comprises an antagonist of a cytokine receptor or cytokine selected from GM-CSF, IL-10, IL-10R, IL-6, IL-6 receptor (IL-6R), IFNγ, IFNGR, IL-2, IL-2R / CD25, MCP-1, CCR2, CCR4, MIPIβ, CCR5, TNFalpha, TNFR1, IL-1 (e.g., IL-1α, IL-1β, IL-1RA), and IL-1 receptor (IL-1R), wherein the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid. The antagonist may be an anti-IL-6 antibody and / or an anti-IL6R antibody. For example, the antagonist may be selected from tocilizumab, cirtoximab, clazakizumab, sarilumab, olokizumab, elsilimomab, ALD518 / BMS-945429, sirukumab (CNTO136), CPSI-2634, ARGX-109, lenzilumab, FE301, and FM101. In some embodiments, the antagonist is tocilizumab and / or cirtoximab. Alternatively, the antagonist may be an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, such as anakinra.

[0130] In some embodiments, the agent comprises a molecule that reduces the regulatory T cell (Treg) population. Agents that reduce (e.g., deplete) the number of Treg cells are known in the art, and include, for example, CD25 depletion, cyclophosphamide administration, anti-CTLA4 antibodies, and regulating glucocorticoid-induced TNLR family-related gene (GITR) function. GITR is a member of the TNLR superfamily that is upregulated on activated T cells and strengthens the immune system. In some embodiments, the treatment comprises administering cyclophosphamide.

[0131] In certain embodiments, an agent capable of treating, preventing, delaying, reducing or attenuating the occurrence or risk of occurrence of an adverse event is administered in one or more doses to a patient prior to the initiation of treatment with a multispecific (e.g., bispecific) antibody as a prophylactic treatment of the adverse event.

[0132] In certain embodiments, an agent capable of treating, preventing, delaying, reducing, or attenuating the occurrence or risk of occurrence of an adverse event is administered to a patient in combination with one or more doses of a multispecific (e.g., bispecific) antibody as a prophylactic treatment of the adverse event. The agent may be administered sequentially (before and / or after) and / or simultaneously in one or more doses with the multispecific (e.g., bispecific) antibody.

[0133] In certain embodiments, an agent capable of treating, preventing, delaying, reducing, or attenuating the occurrence or risk of occurrence of an adverse event is administered to a patient in combination with the initial dose of a multispecific (e.g., bispecific) antibody as a prophylactic treatment of the adverse event. The agent may be administered sequentially (before and / or after) and / or simultaneously in one or more doses with the multispecific (e.g., bispecific) antibody.

[0134] In certain embodiments, an agent capable of treating, preventing, delaying, reducing, or attenuating the occurrence or risk of occurrence of an adverse event is administered to a patient in combination with each increasing dose of a multispecific (e.g., bispecific) antibody as a prophylactic treatment of the adverse event. The agent may be administered sequentially (before and / or after) and / or simultaneously in one or more doses with the multispecific (e.g., bispecific) antibody.

[0135] In certain embodiments, the treatment comprises administering to the patient an initial maintenance dose and one or more additional maintenance doses of a multispecific (e.g., bispecific) antibody, the maintenance doses are administered in a dosing regimen comprising: (i) an initiation phase, followed by administration of an initial maintenance dose of a multispecific (e.g., bispecific) antibody, and optionally one or more additional maintenance doses, in combination with prophylactic treatment to the patient; (ii) a maintenance phase, in which one or more maintenance doses of a multispecific (e.g., bispecific) antibody are administered to the patient. Here, prophylactic treatment involves administering to a patient in one or more doses sequentially (before and / or after) and / or simultaneously with a maintenance dose of a multispecific (e.g., bispecific) antibody, an agent that can treat, prevent, delay, reduce or attenuate the onset or risk of onset of cytokine-driven toxicity (e.g., CRS).

[0136] Administration of multispecific (e.g., bispecific) antibodies in combination with initial phase prophylactic treatment significantly reduces toxicity due to attenuated cytokine release. Thus, it is understood that initial phase maintenance doses can include higher doses of the multispecific (e.g., bispecific) antibodies described herein, e.g., about 8.5 mg to 11.5 mg, about 9 mg to 11 mg, about 9.5 mg to 10.5 mg, e.g., about 10 mg.

[0137] In preferred embodiments, the prophylactic treatment comprises administering at least one dose of the agent (e.g., a CRS agent) prior to a maintenance dose of the multispecific (e.g., bispecific) antibody. In some embodiments, the prophylactic treatment comprises administering one or more doses (e.g., two doses) of the agent (e.g., a CRS agent) prior to the maintenance dose and one or more doses of the agent (e.g., a CRS agent) after the maintenance dose.

[0138] In certain embodiments of any aspect of the invention, prophylactic treatment involves administration of an agent (e.g., a CRS agent) in an amount sufficient to prevent, delay, reduce, or attenuate the onset or risk of onset of an adverse event (e.g., CRS).

[0139] In some embodiments of any aspect of the invention, the prophylactic treatment comprises administering a corticosteroid, such as dexamethasone. In some embodiments, dexamethasone is administered at a dose of about 10-20 mg, preferably intravenously. In embodiments in which dexamethasone is administered as a prophylactic treatment for cytokine-driven toxicity (e.g., CRS), preferably, the dexamethasone is administered in an amount sufficient to attenuate cytokine (e.g., GM-CSF, IL-2, and / or TNF-α) secretion induced by a multispecific (e.g., bispecific) antibody of the invention.

[0140] In certain embodiments of any aspect of the invention, the prophylactic treatment comprises administration of a cytokine receptor or cytokine antagonist, e.g., an antagonist of IL-6, IL-6 receptor (IL-6R), IL-1 (e.g., IL-1α, IL-1β, IL-1RA) and / or IL-1 receptor (IL-1R), wherein the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid.

[0141] In some embodiments of any aspect of the invention, the prophylactic treatment includes an anti-IL-6 antagonist antibody and / or an anti-IL-6R antagonist antibody, such as tocilizumab. In some embodiments, tocilizumab is administered to the patient in one or more doses of about 8 mg / kg, preferably intravenously. In preferred embodiments, tocilizumab is administered at least 30 minutes before the multispecific (e.g., bispecific) antibody. In embodiments in which tocilizumab is administered as a prophylactic treatment for cytokine release syndrome (e.g., CRS), preferably, tocilizumab is administered in an amount sufficient to attenuate IL-6 receptor signaling induced by the multispecific (e.g., bispecific) antibody of the invention.

[0142] In certain embodiments, the initiation phase comprises an initial and a second maintenance dose of a multispecific (e.g., bispecific) antibody administered to the patient in combination with a prophylactic treatment comprising a single dose of tocilizumab administered at least 30 minutes before the maintenance dose, and optionally, the second maintenance dose is administered to the patient 7 days after the initial maintenance dose.

[0143] In certain embodiments of any aspect of the invention, the prophylactic treatment comprises an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, such as anakinra. In certain embodiments, anakinra is administered as a prophylactic treatment for cytokine release syndrome (e.g., CRS), preferably in an amount sufficient to attenuate IL-1 receptor signaling induced by a multispecific (e.g., bispecific) antibody of the invention. Anakinra may be administered at a dose of about 100 mg (e.g., 100 mg ± 20%), preferably subcutaneously. In certain embodiments, anakinra is administered to a patient at a dose of about 100 mg, preferably subcutaneously. In certain embodiments, the prophylactic treatment comprises at least one dose of anakinra administered before the multispecific (e.g., bispecific) antibody and at least one dose of anakinra administered after the multispecific (e.g., bispecific) antibody.

[0144] Anakinra may be administered to the patient as one or more fixed doses between about 16 hours and about 2 hours before the multispecific (e.g., bispecific) antibody, or optionally as a single fixed dose between about 20 hours and about 22 hours after the multispecific (e.g., bispecific) antibody. In certain embodiments of any aspect of the invention, anakinra is administered as follows: (i) a single fixed dose between about 16 hours and about 8 hours prior to a multispecific (e.g., bispecific) antibody; and / or (ii) a single fixed dose between about 4 hours and about 2 hours prior to a multispecific (e.g., bispecific) antibody; Here, if desired, an additional fixed dose of anakinra may be administered between about 20 hours and about 22 hours after the multispecific (eg, bispecific) antibody.

[0145] In certain embodiments, the initiation phase comprises an initial and a second maintenance dose of a multispecific (e.g., bispecific) antibody administered to a patient in combination with a prophylactic treatment, respectively, wherein: (i) the first maintenance dose is administered in combination with: a first dose of anakinra between about 16 hours and about 8 hours before the maintenance dose; a second dose of anakinra between about 4 hours and about 2 hours before the maintenance dose; and a third dose of anakinra between about 20 hours and about 22 hours after the maintenance dose; and (ii) the second maintenance dose is administered in combination with: a fourth dose of anakinra between about 4 hours and about 2 hours before the maintenance dose; and a fifth dose of anakinra between about 20 hours and about 22 hours after the maintenance dose; Optionally, a second maintenance dose is administered to the patient 7 days after the first maintenance dose.

[0146] In some embodiments of any aspect of the invention, the prophylactic treatment comprises administering tocilizumab (e.g., about 8 mg / kg, preferably intravenously) together with dexamethasone (e.g., about 10-20 mg, preferably intravenously). In some embodiments, the prophylactic treatment comprises administering anakinra (e.g., about 100 mg, preferably subcutaneously) together with dexamethasone (e.g., about 10-20 mg, preferably intravenously).

[0147] In certain embodiments of any aspect of the invention, prophylactic treatment includes administration of symptomatic support, including administration of antipyretics, analgesics, antivirals, and / or antibiotics. In certain embodiments, administration of symptomatic support includes administration of antivirals (e.g., acyclovir, oseltamivir, zanamivir, and / or equivalents) and / or antibiotics (e.g., trimethoprim-sulfamethoxazole, levofloxacin, and / or equivalents). In certain embodiments, prophylactic treatment includes administration of a seizure prophylaxis (e.g., levetiracetam). Symptomatic and / or seizure prophylaxis may be administered in addition to an agent capable of treating, preventing, delaying, reducing, or attenuating the occurrence or risk of occurrence of an adverse event.

[0148] In certain embodiments of any aspect of the invention, an agent capable of treating, preventing, delaying, reducing, or attenuating the occurrence of, or the risk of, an adverse event is administered to a patient if the patient experiences an adverse event associated with administration of a multispecific (e.g., bispecific) antibody. In certain embodiments, treatment comprises administering a therapeutic amount of the agent, or an amount sufficient to partially or completely alleviate or ameliorate the adverse event (e.g., CRS) or its symptoms.

[0149] If a patient develops an adverse event (e.g., CRS) after administration of a multispecific (e.g., bispecific) antibody of the present invention, treatment may further include administering an anti-IL-6R antagonist antibody, e.g., tocilizumab. In some embodiments, tocilizumab is administered to the patient as a single dose of about 8 mg / kg, preferably administered intravenously. In some embodiments, treatment may further include administering one or more additional doses of an IL-6R antagonist antibody, e.g., tocilizumab, to the patient. In some embodiments, tocilizumab is administered to the patient in one or more additional doses of about 8 mg / kg, preferably administered intravenously.

[0150] In certain embodiments, if a patient develops an adverse event (e.g., CRS) after administration of a multispecific (e.g., bispecific) antibody of the invention, treatment may further include administration of an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, e.g., anakinra. In certain embodiments, anakinra is administered to the patient as one or more fixed doses of about 100 mg, preferably administered subcutaneously. In certain embodiments, anakinra is administered to the patient twice daily, preferably in a fixed dose of about 100 mg, preferably administered subcutaneously.

[0151] In some embodiments, if an adverse event (e.g., CRS) occurs, treatment may further include administration of an IL-6 antagonist antibody, such as siltuximab. In some embodiments, siltuximab is administered to the patient as a single dose of about 11 mg / kg, preferably administered intravenously.

[0152] In some embodiments, if an adverse event (e.g., CRS) occurs, treatment may further include administering a corticosteroid, such as methylprednisolone or dexamethasone, to the patient. In some embodiments, dexamethasone is administered at a dose of about 10-20 mg, preferably intravenously. In some embodiments, methylprednisolone is administered at a dose of about 1 mg / kg to about 5 mg / kg per day, e.g., about 2 mg / kg per day.

[0153] In some embodiments, additional treatment may be based on the stage of CRS. A modified version of the common CTCAE CRS grading scale has been established for grading and treatment of CRS and is detailed in Table 10.

[0154] [Table 10]

[0155] For example, in embodiments in which a patient has Grade 2 CRS after administration of a multispecific (e.g., bispecific) antibody, treatment may further include administration of a first line treatment comprising administration of an initial dose of an anti-IL-6 antagonist antibody and / or an anti-IL-6R antagonist antibody, e.g., tocilizumab. In certain embodiments, tocilizumab is administered intravenously to the patient as a single dose of about 8 mg / kg.

[0156] In another embodiment, in which the patient has Grade 2 CRS after administration of a multispecific (e.g., bispecific) antibody, the treatment may further comprise administering a first-line therapy comprising administering one or more fixed dose(s) of an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, e.g., anakinra. Anakinra may be administered at a dose of about 100 mg (e.g., 100 mg ± 20%), preferably subcutaneously. In some embodiments, anakinra is administered to the patient as one or more fixed dose(s) of about 100 mg, preferably subcutaneously. In some embodiments, anakinra is administered to the patient twice daily, preferably at a fixed dose of about 100 mg, preferably subcutaneously.

[0157] If the patient experiences a rapid onset of Grade 2 CRS or a Grade 3 or higher CRS after administration of the multispecific (e.g., bispecific) antibody, treatment may further include administration of a first-line therapy comprising: (i) anti-IL-6 antagonist antibodies and / or anti-IL-6R antagonist antibodies, such as tocilizumab; and (ii) Corticosteroids, such as dexamethasone or methylprednisolone.

[0158] In some embodiments, tocilizumab is administered intravenously to a patient at a dose of about 8 mg / kg.

[0159] Alternatively, if the patient experiences a rapid onset of Grade 2 CRS or an onset of Grade 3 or higher CRS after administration of the multispecific (e.g., bispecific) antibody, treatment may further include administration of a first-line therapy comprising: (i) an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, such as anakinra; and (ii) Corticosteroids, such as dexamethasone or methylprednisolone.

[0160] In some embodiments, anakinra is administered to a patient as one or more fixed dose(s) of about 100 mg, preferably administered subcutaneously. In some embodiments, anakinra is administered to a patient as a fixed dose of about 100 mg twice daily, preferably administered subcutaneously.

[0161] The corticosteroid can be administered sequentially (before or after) or simultaneously with (i) an anti-IL-6 antagonist antibody and / or an anti-IL-6R antagonist antibody, e.g., tocilizumab, or (ii) an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, e.g., anakinra. In some embodiments, the corticosteroid is dexamethasone. In some embodiments, dexamethasone is administered at a dose of about 10-20 mg, preferably intravenously. In some embodiments, the corticosteroid is methylprednisolone. In some embodiments, methylprednisolone is administered at a dose of about 1 mg / kg to about 5 mg / kg per day, e.g., about 2 mg / kg per day.

[0162] In some embodiments, first-line treatment includes administering symptomatic treatments for CRS, including administering antipyretics, analgesics, and / or antibiotics. In some embodiments, first-line treatment includes administering a prophylactic agent for stroke (e.g., levetiracetam). Symptomatic treatments and / or prophylactic agents may be administered in addition to agents capable of treating, preventing, delaying, reducing, or attenuating the occurrence or risk of occurrence of an adverse event.

[0163] In certain embodiments of any aspect of the invention, if a patient develops CRS after administration of a dose (e.g., a starting dose or a maintenance dose) of a multispecific (e.g., bispecific) antibody, the patient may be administered the next dose (e.g., the next starting dose or the next maintenance dose) when the toxicity described herein reaches a grade ≦1. In other embodiments in which the patient develops CRS, the patient may be administered the next dose when the toxicity reaches baseline levels.

[0164] If CRS does not resolve or worsens in response to first-line therapy, treatment may further include administration of a second-line therapy including: (i) one or more (e.g., one, two, three, four, or five or more) additional doses of an anti-IL-6 antagonist antibody and / or an anti-IL-6R antagonist antibody, e.g., tocilizumab; and (ii) one or more (e.g., one, two, three, four, or five or more) additional doses of a corticosteroid, e.g., dexamethasone or methylprednisolone.

[0165] In some embodiments, one or more additional doses of tocilizumab are administered intravenously to a patient at a dose of about 8 mg / kg. The corticosteroid can be administered sequentially (before or after) or simultaneously with the anti-IL-6 antagonist antibody and / or anti-IL-6R antagonist antibody, e.g., tocilizumab. In some embodiments, the corticosteroid is dexamethasone. In some embodiments, dexamethasone is administered intravenously at a dose of about 10-20 mg. In some embodiments, the corticosteroid is methylprednisolone. In some embodiments, methylprednisolone is administered at a dose of about 1 mg / kg to about 5 mg / kg per day, for example, at a dose of about 2 mg / kg per day.

[0166] If CRS does not resolve or worsens in response to the second-line therapy, treatment may further include administration of a third-line therapy comprising administration of an antagonist of a cytokine receptor or cytokine selected from GM-CSF, IL-10, IL-10R, IL-6, IL-6 receptor (IL-6R), IFN, IFNGR, IL-2, IL-2R / CD25, MCP-1, CCR2, CCR4, MIPIβ, CCR5, TNFα, TNFR1, IL-1 (e.g., IL-1α, IL-1β, IL-1RA), and IL-1 receptor (IL-1R), where the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid. The antagonist may be an anti-IL-6 antibody and / or an anti-IL-6R antibody. For example, the antagonist may be selected from tocilizumab, siltuximab, clazakizumab, sarilumab, olokizumab, elcilimomab, ALD518 / BMS-945429, sirukumab (CNTO136), CPSI-2634, ARGX-109, lenzilumab, FE301, and FM101. In some embodiments, the third-line treatment includes administration of siltuximab. In some embodiments, siltuximab is administered to the patient as a single dose of about 11 mg / kg, preferably intravenously. Alternatively, the antagonist may be an anti-IL-1 antagonist and / or an anti-IL-1R antagonist, such as anakinra.

[0167] If CRS does not disappear or worsens in response to third-line therapy, treatment may further include administering a fourth-line therapy, which includes administering a molecule that reduces the regulatory T cell (Treg) population. Molecules that reduce (e.g., deplete) the number of Treg cells are known in the art, and include, for example, CD25 depletion, cyclophosphamide administration, anti-CTLA4 antibodies, and glucocorticoid-induced TNLR family-related gene (GITR) function modulation. GITR is a member of the TNLR superfamily that is upregulated on activated T cells and strengthens the immune system. In some embodiments, the fourth-line therapy includes administering cyclophosphamide.

[0168] In some embodiments, if an adverse event (e.g., neutropenia, infection) occurs, treatment may further include symptomatic treatment, including administration of antipyretics, analgesics, antivirals, and / or antibiotics. In some embodiments, a prophylactic drug (e.g., levetiracetam) may be administered to the patient. If the patient develops neutropenia (e.g., at least grade 3 neutropenia), treatment may further include administration of an antibiotic (e.g., levofloxacin or equivalent). If the patient develops a viral infection (e.g., influenza), treatment may further include administration of oseltamivir, zanamivir, and / or equivalents.

[0169] In certain embodiments of any aspect of the invention, if a patient develops a viral infection (e.g., influenza A / B, SARS-CoV-2) after administration of a dose (e.g., a starting dose or a maintenance dose) of a multispecific (e.g., bispecific) antibody, a subsequent dose (e.g., a subsequent starting dose or a subsequent maintenance dose) may be administered to the patient when symptoms of the infection have resolved. In other embodiments in which the patient develops a viral infection, the subsequent administration may be administered at least 14 days after a negative test for viral infection, e.g., a negative PCR viral panel, and / or a positive test for viral infection, e.g., a positive PCR viral panel. The viral panel (e.g., a PCR viral panel) can test for influenza A / B, respiratory syncytial virus (RSV), parainfluenza virus, metapneumovirus, adenovirus, and / or SARS-CoV-2.

[0170] multispecific antibodies Multispecific (e.g., bispecific) antibodies of the present invention specifically bind to BCMA and CD3. The terms "antibody to BCMA and CD3," "anti-BCMA anti-CD3 antibody," or "antibody that binds BCMA and CD3" refer to a multispecific antibody (e.g., a bispecific antibody) that can bind to BCMA and CD3 with sufficient affinity so that the antibody is useful as a therapeutic. This is achieved by generating a molecule that includes a first antibody or antigen-binding fragment that binds to BCMA and a second antibody or antigen-binding fragment that binds CD3. Such multispecific antibodies may be trispecific or bispecific. In a preferred embodiment, the multispecific antibody is a bispecific antibody.

[0171] As used herein, the term "BCMA" relates to the human B-cell maturation antigen, also known as BCMA; TR17_HUMAN, TNFRSF17 (UniProt Q02223), a member of the tumor necrosis receptor superfamily that is preferentially expressed on differentiated plasma cells. The extracellular domain of BCMA consists of amino acids 1-54 (or 5-51) according to UniProt. As used herein, the terms "antibody against BCMA," "anti-BCMA antibody," or "antibody that binds to BCMA" refer to an antibody that specifically binds to the extracellular domain of BCMA.

[0172] The term "specifically binds to BCMA" refers to an antibody that is capable of binding to a defined target with sufficient affinity such that the antibody is useful as a BCMA-targeted therapeutic. In some embodiments, an antibody that specifically binds BCMA does not bind to other antigens or does not bind to other antigens with sufficient affinity to produce a physiological effect.

[0173] In some embodiments, the extent of binding of an anti-BCMA antibody to an unrelated, non-BCMA protein is about 10-fold, preferably 100-fold or more less than the binding of the antibody to BCMA, as measured, for example, by surface plasmon resonance (SPR), e.g., Biacore®, enzyme-linked immunosorbent assay (ELISA), or flow cytometry (FACS). -8 M or less, preferably 10 -8 M~10 -13 M, more preferably 10 -9 M~10 -13 It has a dissociation constant (Kd) of M.

[0174] In one embodiment the anti-BCMA antibody binds to an epitope of BCMA that is conserved between BCMA from different species, preferably human and cynomolgus monkey, and more preferably also binds to mouse and rat BCMA.

[0175] Preferably, the anti-BCMA antibody specifically binds to a group of BCMAs consisting of human BCMA and BCMA from non-human mammals, preferably cynomolgus monkeys, mice, and / or rats. The anti-BCMA antibody is analyzed for binding to human BCMA by ELISA using plate-bound BCMA. In this assay, the amount of plate-bound BCMA is preferably 1.5 μg / mL, and the anti-BCMA antibody is used at a concentration ranging from 0.1 pM to 200 nM.

[0176] The term "CD3" refers to the human CD3 protein multimeric subunit complex. The CD3 protein multimeric subunit complex is composed of six distinct polypeptide chains. Thus, the term includes the CD3 gamma chain (SwissProt P09693), the CD3 delta chain (SwissProt P04234), two CD3 epsilon chains (SwissProt P07766), and one CD3 zeta chain homodimer (SwissProt 20963), which are associated with the T cell receptor alpha and beta chains. The term encompasses "full-length," native CD3, as well as any CD3 variants, isoforms, and species homologs that are naturally expressed by cells (including T cells) or that can be expressed on cells transfected with genes or cDNAs encoding those polypeptides.

[0177] The term "specifically binds to CD3" refers to an antibody that is capable of binding to a defined target with sufficient affinity such that the antibody is useful as a CD3-targeted therapeutic. In some embodiments, an antibody that specifically binds to CD3 does not bind to other antigens or does not bind to other antigens with sufficient affinity to produce a physiological effect.

[0178] Multispecific (e.g., bispecific) antibodies of the invention can be analyzed for binding to CD3 by SPR, e.g., Biacore®. In one embodiment, the bispecific antibody has a surface plasmon resonance (SPR) assay, preferably a Biacore 8K assay at 25°C, of ​​about 10 -7 Dissociation constant (KD) of approximately 10 -8 KD below M, about 10 -9 KD below M, about 10 -10 KD below M, about 10 -11 KD below M, or about 10 -12 In a preferred embodiment, the bispecific antibody binds to human CD3 with a KD of about 10 -8 It binds to human CD3 with a dissociation constant (KD) of less than M.

[0179] As used herein, the term "antibody" encompasses a variety of antibody structures, including, but not limited to, monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), and antibody fragments, so long as they exhibit the desired antigen-binding activity.

[0180] A "heavy chain" comprises a heavy chain variable region (abbreviated herein as "VH") and a heavy chain constant region (abbreviated herein as "CH"). The heavy chain constant region may comprise heavy chain constant domains CH1, CH2, and CH3 (antibody classes IgA, IgD, and IgG), and optionally heavy chain constant domain CH4 (antibody classes IgE and IgM).

[0181] A "light chain" comprises a light chain variable domain (abbreviated herein as "VL") and a light chain constant domain (abbreviated herein as "CL"). The variable regions VH and VL can be further subdivided into hypervariable regions called complementarity-determining regions (CDRs) and highly conserved regions called framework regions (FRs). Each VH and VL is 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. The "constant domains" of the heavy and light chains are not directly involved in binding the antibody to a target, but exert various effector functions.

[0182] The binding of an antibody to its target antigen or epitope is mediated by complementarity-determining regions (CDRs). CDRs are regions of high sequence variability located within the variable regions of antibody heavy and light chains, forming the antigen-binding site. CDRs are the primary elements determining antigen specificity. Generally, antibody heavy and light chains each contain three non-contiguous CDRs. The CDR3 regions of antibody heavy and light chains play a particularly important role in the binding specificity / affinity of the antibodies according to the present invention, and therefore provide a further aspect of the present invention.

[0183] As used herein, the term "antigen-binding fragment" encompasses any naturally occurring or artificially constructed configuration of an antigen-binding polypeptide containing one, two, or three light chain CDRs and / or one, two, or three heavy chain CDRs, which polypeptide is capable of binding to an antigen. Thus, the term refers to a molecule other than an intact antibody that contains a portion of an intact antibody that binds to the antigen bound by the intact antibody. Examples of antibody fragments include, but are not limited to, Fv, Fab, Fab', Fab'-SH, F(ab')2; bispecific antibodies (diabodies); linear antibodies; single-chain antibody molecules (e.g., scFv); and multispecific antibodies formed from antibody fragments.

[0184] The terms "Fab fragment" and "Fab" are used interchangeably herein and comprise a single light chain (i.e., constant domains C L and V L ) and a single heavy chain (i.e., constant domains C H and V H ). The heavy chain of a Fab fragment cannot form disulfide bonds with another heavy chain.

[0185] A "Fab' fragment" contains a single light chain and a single heavy chain, but also contains the CH1 and VH domains, as well as the region of the heavy chain between the CH1 and CH2 domains necessary for interchain disulfide bond formation. Thus, two Fab' fragments can associate via disulfide bond formation to form an F(ab')2 molecule.

[0186] A "F(ab')2 fragment" contains two light chains and two heavy chains, each of which contains a portion of the constant region necessary for interchain disulfide bond formation between the two heavy chains.

[0187] An "Fv fragment" contains only the variable regions of the heavy and light chains; it does not contain the constant regions.

[0188] A "single domain antibody" is an antibody fragment comprising a single antibody domain unit (eg, VH or VL).

[0189] A "single-chain Fv" ("scFv") is an antibody fragment comprising the VH and VL domains of an antibody linked together to form a single chain. A polypeptide linker is generally used to link the VH and VL domains of an scFv.

[0190] A "tandem scFv", also known as a TandAb®, is a single-chain Fv molecule formed by covalently linking two scFvs in a tandem orientation with a flexible peptide linker.

[0191] "Bispecific T cell inducers (BiTE®) are fusion proteins consisting of two single-chain variable fragments (scFv) on a single peptide chain. One scFv binds to T cells via the CD3 receptor, and the other scFv binds to a tumor cell antigen.

[0192] "Diabodies" are small bivalent and bispecific antibody fragments in which a heavy-chain variable domain (VH) and a light-chain variable domain (VL) on the same polypeptide chain are connected by a peptide linker that is too short to allow pairing between the two domains on the same chain (Kipriyanov, Int. J. Cancer 77 (1998), 763-772). This forces pairing with complementary domains on another chain, promoting the assembly of a dimeric molecule with two functional antigen-binding sites.

[0193] "DARPins" are bispecific ankyrin repeat molecules. DARPins are derived from the natural ankyrin protein present in the human genome and are one of the most abundant types of binding proteins. DARPin library modules are defined by the sequences of 229 ankyrin repeat proteins; the initial design contained 229 ankyrin repeats, and subsequent refinements added an additional 2,200 ankyrin repeats. These modules serve as building blocks for DARPin libraries. Library modules resemble human genome sequences. DARPins consist of 4-6 modules. Each module is approximately 3.5 kDa, resulting in an average DARPin size of 16-21 kDa. Binder selection is performed by ribosome display, a completely cell-free method described in He M. and Taussig MJ., Biochem Soc Trans. 2007, Nov;35(Pt 5):962-5.

[0194] The sequences of the CDRs can be identified by reference to any numbering system known in the art, such as the Kabat system (Kabat, EA, et al., Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, National Institutes of Health, Bethesda, MD (1991)); the Chothia system (Chothia & Lesk, "Canonical Structures for the Hypervariable Regions of Immunoglobulins," J. Mol. Biol. 196, 901-917 (1987)); or the IMGT system (Lefranc et al., "IMGT Unique Numbering for Immunoglobulin and Cell Receptor Variable Domains and Ig superfamily V-like domains," Dev. Comp. Immunol. 27, 55-77 (2003)).

[0195] [Table 11]

[0196] For the heavy chain constant region amino acid positions discussed herein, numbering is according to the EU numbering system first described in Edelman, GM, et al., Proc. Natl. Acad. Sci. USA 63 (1969) 78-85. Edelman's EU numbering system is also described in Kabat et al. (1991) supra. Thus, the terms "EU index according to Kabat," "EU index," "Kabat's EU index," or "EU numbering" in the context of heavy chains refer to the residue numbering system based on the human IgG1 EU antibody of Edelman et al. as defined in Kabat et al. (1991). The numbering system used for light chain constant region amino acid sequences is similarly described in Kabat et al. (supra). Thus, as used herein, "numbered according to Kabat" refers to the numbering system described in Kabat et al. (supra).

[0197] The antibodies and antigen-binding fragments thereof of the present invention may be derived from any species by recombinant means. For example, the antibodies or antigen-binding fragments may be mouse, rat, goat, horse, cow, chicken, rabbit, camel, donkey, human, or chimeric versions thereof. For use in human administration, antibodies or antigen-binding fragments of non-human origin may be genetically or structurally modified to render them less antigenic when administered to a human patient.

[0198] Human or humanized antibodies are particularly preferred, especially as recombinant human or humanized antibodies.

[0199] The term "humanized antibody" refers to an antibody in which the framework or "complementarity-determining regions" (CDRs) have been altered to comprise CDRs from an immunoglobulin with different specificity compared to those of the parent immunoglobulin. For example, murine CDRs can be grafted into the framework regions of a human antibody to prepare a "humanized antibody." See, e.g., Riechmann, L., et al., Nature 332 (1988) 323-327; and Neuberger, MS, et al., Nature 314 (1985) 268-270. In certain embodiments, a "humanized antibody" is one in which the constant region has been additionally modified or altered from that of the original antibody to generate the properties of the antibody according to the invention, particularly with respect to Clq binding and / or Fc receptor (FcR) binding.

[0200] The term "human antibody" refers to an antibody having an amino acid sequence corresponding to that of an antibody produced by a human or human cell, or an antibody derived from a non-human source that utilizes the human antibody repertoire or other human antibody coding sequences. This definition of human antibody specifically excludes humanized antibodies, which comprise non-human antigen-binding residues. Human antibodies can be generated using a variety of techniques known in the art, such as phage display libraries.

[0201] The term "chimeric antibody" refers to an antibody comprising a variable region, i.e., a binding region, from one source or species and at least a portion of a constant region from a different source or species, typically produced by recombinant DNA technology. Chimeric antibodies comprising a murine variable region and a human constant region are preferred. Other preferred embodiments of "chimeric antibodies" encompassed by the present invention are those in which the constant region has been modified or changed from that of the original antibody to generate the properties of the antibodies according to the present invention, particularly with respect to Clq binding and / or Fc receptor (FcR) binding. Such chimeric antibodies are also referred to as "class-switched antibodies." Chimeric antibodies are the product of the expression of immunoglobulin genes comprising DNA segments encoding immunoglobulin variable regions and DNA segments encoding immunoglobulin constant regions. Methods for producing chimeric antibodies, including conventional recombinant DNA and gene transfer techniques, are well known in the art. See, e.g., Morrison, SL, et al., Proc. Natl. Acad. Sci. USA 81 (1984) 6851-6855; U.S. Patent Nos. 5,202,238 and 5,204,244.

[0202] The terms "Fc region" and "Fc" are used interchangeably herein and refer to the portion of a native immunoglobulin formed by two Fc chains. Each "Fc chain" contains a constant domain and a constant domain CH3. Each Fc chain may also contain a hinge region. Native Fc regions are homodimers. In certain embodiments, the Fc region may contain modifications to effect Fc heterodimerization.

[0203] The term "Fc portion" refers to the portion of an antibody or antigen-binding fragment thereof of the present invention that corresponds to the Fc region.

[0204] Heavy chain constant regions are classified into five major classes: IgA, IgG, IgD, IgE, and IgM, each with a characteristic effector function designated by its isotype. For example, IgG is divided into four subclasses, called IgG1, IgG2, IgG3, and IgG4. Ig molecules interact with multiple cell receptor classes. For example, IgG molecules interact with three classes of Fcγ receptors specific for IgG class antibodies: FcγRI, FcγRII, and FcγRIII. It has been reported that sequences important for IgG binding to FcγR receptors reside in the CH2 and CH3 domains.

[0205] The antibody or antigen-binding fragment thereof of the present invention may be of any isotype, i.e., IgA, IgD, IgE, IgG, and IgM, as well as synthetic multimers of four-chain immunoglobulin (Ig) structures. In a preferred embodiment, the antibody or antigen-binding fragment thereof is an IgG isotype. The antibody or antigen-binding fragment may be of any IgG subclass, for example, an IgG1, IgG2, IgG3, or IgG4 isotype. In a preferred embodiment, the antibody or antigen-binding fragment thereof is an IgG1 isotype.

[0206] In some embodiments, the antibody comprises a heavy chain constant region of an IgG isotype. In some embodiments, the antibody comprises a portion of a heavy chain constant region of an IgG isotype. In some embodiments, the IgG constant region or portion thereof is an IgG1, IgG2, IgG3, or IgG4 constant region. Preferably, the IgG constant region or portion thereof is an IgG1 constant region.

[0207] The antibodies or antigen-binding fragments thereof of the present invention may comprise a lambda light chain or a kappa light chain.

[0208] In preferred embodiments, the antibody or antigen-binding fragment thereof comprises a light chain that is a kappa light chain. In some embodiments, the antibody or antigen-binding fragment comprises a light chain that comprises a light chain constant region (CL) that is a kappa constant region.

[0209] In some embodiments, the antibody comprises a light chain comprising a light chain variable region (VL) that is a kappa variable region. Preferably, the kappa light chain comprises a VL that is a kappa VL and a CL that is a kappa CL.

[0210] Alternatively, the antibody or antigen-binding fragment thereof may comprise a light chain that is a λ light chain. In some embodiments, the antibody or antigen-binding fragment comprises a light chain that comprises a light chain constant region (CL) that is a λ constant region. In some embodiments, the antibody comprises a light chain that comprises a light chain variable region (VL) that is a λ variable region.

[0211] Engineered antibodies and antigen-binding fragments thereof include those in which modifications have been made to framework residues within VH and / or VL. Such modifications can improve the properties of the antibody, for example, to reduce the immunogenicity of the antibody and / or to improve production and purification of the antibody.

[0212] The antibodies and antigen-binding fragments thereof described herein can be further modified by conventional techniques known in the art, such as amino acid deletion(s), insertion(s), substitution(s), addition(s) and / or recombination and / or other modification(s) known in the art, either alone or in combination. Methods for introducing such alterations into the DNA sequence underlying the amino acid sequence of an immunoglobulin chain are well known to those skilled in the art.

[0213] The antibodies and antigen-binding fragments thereof of the present invention also include derivatives that have been modified (e.g., by the covalent attachment of any type of molecule to the antibody) such that the covalent attachment does not prevent the antibody from binding to its epitope or otherwise impair the biological activity of the antibody. Examples of suitable derivatives include, but are not limited to, fucosylated antibodies, glycosylated antibodies, acetylated antibodies, pegylated antibodies, phosphorylated antibodies, amidated antibodies, etc.

[0214] Minor variations in the amino acid sequences of the antibodies of the invention are contemplated to be encompassed by the present invention, provided that the variations in the amino acid sequence(s) maintain at least 75%, more preferably at least 80%, at least 90%, at least 95%, and most preferably at least 99% sequence identity to an antibody or antigen-binding fragment thereof of the invention as defined anywhere herein.

[0215] The antibodies of the present invention may include variants in which an amino acid residue from one species is substituted with the corresponding residue in another species, either at a conserved or non-conserved position. In one embodiment, an amino acid residue at a non-conserved position is substituted with a conserved or non-conserved residue. Conservative amino acid substitutions are particularly contemplated.

[0216] A "conservative amino acid substitution" is one in which an amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art, and include basic side chains (e.g., lysine, arginine, or histidine), acidic side chains (e.g., aspartic acid or glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, or cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, or tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, or histidine). Thus, when an amino acid in a polypeptide is substituted with another amino acid from the same side chain family, the amino acid substitution is considered conservative. The inclusion of conservatively modified variants in the antibodies of the invention does not exclude other forms of variants, such as polymorphic variants, interspecies homologs, and alleles.

[0217] "Non-conservative amino acid substitutions" include (i) substitutions of a residue having an electropositive side chain (e.g., Arg, His, or Lys) for or by an electronegative residue (e.g., Glu or Asp), (ii) substitutions of a hydrophilic residue (e.g., Ser or Thr) for a hydrophobic residue (e.g., Ala, Leu, Ile, Phe, or Val), (iii) substitutions of cysteine ​​or proline for or by other residues, or (iv) substitutions of a residue having a bulky hydrophobic or aromatic side chain (e.g., Val, His, Ile, or Trp) for or by one having a small side chain (e.g., Ala or Ser) or no side chain (e.g., Gly).

[0218] Antibody Format Formats for multispecific, for example bispecific antibodies, are known in the art. For example, bispecific antibody formats are described in Kontermann RE, mAbs 4:2 1-16 (2012); Holliger P., Hudson PJ, Nature Biotech.23 (2005) 1126-1136, Chan AC, Carter PJ Nature Reviews Immunology 10, 301-316 (2010) and Cuesta AM et al., Trends Biotech 28 (2011) 355-362.

[0219] The multispecific, e.g., bispecific, antibodies of the present invention can have any format. Multispecific and bispecific antibody formats include, for example, multivalent single-chain antibodies, diabodies, and triabodies, as well as antibodies with the constant domain structure of a full-length antibody to which additional antigen-binding domains (e.g., single-chain Fvs, tandem scFvs, VH and / or VL domains, Fab, or (Fab)2) are linked via one or more peptide linkers, and antibody mimetics such as DARPins. In one embodiment, the multispecific, e.g., bispecific, antibodies of the present invention have an scFv format, such as bispecific T cell engineer (BITE®). In one embodiment, an antibody of the invention is a single chain antibody comprising a first domain that binds to BCMA, a second domain that binds to a T cell antigen (e.g., CD3), and a third domain comprising two polypeptide monomers, each comprising a hinge, a CH2 domain, and a CH3 domain, wherein the two polypeptide monomers are fused to each other via a peptide linker (e.g., (hinge-CH2-CH3-linker-hinge-CH2-CH3).

[0220] The "valency" of an antibody refers to the number of binding domains. Thus, the terms "bivalent," "trivalent," and "multivalent" refer to the presence of two binding domains, three binding domains, and multiple binding domains, respectively. Multispecific antibodies, e.g., bispecific antibodies, of the invention may have multiple binding domains capable of binding to each target antigen (i.e., the antibody is trivalent or multivalent). In preferred embodiments, multispecific antibodies, e.g., bispecific antibodies, of the invention have two or more binding domains capable of binding to the same epitope on each target antigen. In some embodiments, multispecific antibodies, e.g., bispecific antibodies, of the invention have two or more binding domains capable of binding to different epitopes on each target antigen.

[0221] Multispecific antibodies, e.g., bispecific antibodies, of the present invention may be bivalent, trivalent, or tetravalent. In a preferred embodiment, the multispecific antibody, e.g., bispecific antibody, is trivalent, and preferably, the trivalent antibody is bivalent for BCMA. Thus, the bispecific antibody may be trivalent, wherein the trivalent antibody is bivalent for BCMA.

[0222] Multispecific antibodies, e.g., bispecific antibodies, may be full-length from a single species or may be chimerized or humanized. In antibodies with three or more antigen-binding domains, some of the binding domains may be identical, as long as the protein has binding domains for two different antigens.

[0223] The multispecific antibodies, e.g., bispecific antibodies, of the present invention may have a bispecific heterodimer format. In some embodiments, the bispecific antibodies comprise two different heavy chains and two different light chains. In other embodiments, the multispecific antibodies, e.g., bispecific antibodies, comprise two identical light chains and two different heavy chains. In some embodiments, in the multispecific antibodies, e.g., bispecific antibodies, of the present invention, one of the two heavy-light chain pairs (HC / LC) specifically binds to CD3, and the other specifically binds to BCMA.

[0224] In embodiments in which the bispecific antibodies of the invention are bivalent, they may comprise one anti-BCMA antibody and one anti-CD3 antibody (referred to herein as a "1+1" format).

[0225] In embodiments where the BCMA antibody and the CD3 antibody are Fabs, the bivalent bispecific antibody in a 1+1 format may have the format: CD3 Fab - BCMA Fab (i.e., when Fc is absent). Alternatively, the bispecific antibody may have the format: Fc - CD3 Fab - BCMA Fab; Fc-BCMAFab-CD3Fab; or BCMA Fab - Fc - CD3 Fab (i.e., when Fc is present). In a preferred embodiment, the bivalent bispecific antibody has the format BCMA Fab - Fc - CD3 Fab.

[0226] "CD3 Fab - BCMA Fab" means that the CD3 Fab is linked via its N-terminus to the C-terminus of the BCMA Fab. "Fc - BCMA Fab - CD3 Fab" means that BCMA Fab is bound via its C-terminus to the N-terminus of Fc, and CD3 Fab is bound via its C-terminus to the N-terminus of BCMA Fab. "Fc - CD3 Fab - BCMA Fab" means that CD3 Fab is bound via its C-terminus to the N-terminus of Fc, and BCMA Fab is bound via its C-terminus to the N-terminus of CD3 Fab. "BCMA Fab - Fc - CD3 Fab" means that the BCMA and CD3 Fab fragments are linked via their C-termini to the N-terminus of Fc.

[0227] In embodiments in which the bispecific antibodies of the invention are trivalent, they may comprise two anti-BCMA antibodies and one anti-CD3 antibody (referred to herein as a "2+1" format).

[0228] In embodiments where the BCMA antibody and the CD3 antibody are Fabs, the trivalent bispecific antibody in a 2+1 format may have the format: CD3 Fab - BCMA Fab - BCMA Fab; or BCMA Fab - CD3 Fab - BCMA Fab (i.e., when Fc is absent). Alternatively, the bispecific antibody may have the following format: BCMA Fab - Fc - CD3 Fab - BCMA Fab; BCMA Fab - Fc - BCMA Fab - CD3 Fab; or CD3 Fab - Fc - BCMA Fab - BCMA Fab (i.e., when Fc is present). In a preferred embodiment, the trivalent bispecific antibody has the format BCMA Fab - Fc - CD3 Fab - BCMA Fab.

[0229] "CD3 Fab - BCMA Fab - BCMA Fab" means that a CD3 Fab is bound via its C-terminus to the N-terminus of a first BCMA Fab, and the first BCMA Fab is bound via its C-terminus to the N-terminus of a second BCMA Fab. "BCMA Fab - CD3 Fab - BCMA Fab" means that a first BCMA Fab is bound via its C-terminus to the N-terminus of a CD3 Fab, and a CD3 Fab is bound via its C-terminus to the N-terminus of a second BCMA Fab. "BCMA Fab - Fc - CD3 Fab - BCMA Fab" means that a first BCMA Fab and a CD3 Fab are bound via their C-terminus to the N-terminus of the Fc, and a second BCMA Fab is bound via its C-terminus to the N-terminus of the CD3 Fab. "BCMA Fab - Fc - BCMA Fab - CD3 Fab" means that a first BCMA Fab and a second BCMA Fab are bound via their C-terminus to the N-terminus of Fc, and a CD3 Fab is bound via its C-terminus to the N-terminus of the second BCMA Fab. "CD3 Fab - Fc - BCMA Fab - BCMA Fab" means that a CD3 Fab and a first BCMA Fab are bound via their C-terminus to the N-terminus of Fc, and a second BCMA Fab is bound via their C-terminus to the N-terminus of the first BCMA Fab.

[0230] In one embodiment, a bispecific antibody of the invention comprises no more than one BCMA Fab that specifically binds BCMA, no more than one CD3 Fab that specifically binds CD3 and no more than one Fc portion.

[0231] In some embodiments, the bispecific antibody comprises no more than one CD3 Fab that specifically binds CD3, no more than two BCMA Fabs that specifically bind BCMA, and no more than one Fc portion. In some embodiments, no more than one CD3 Fab and no more than one BCMA Fab are linked to the Fc portion, with the linkage being performed via a C-terminal linkage to the hinge region of the Fc portion of the Fab(s). In some embodiments, a second BCMA Fab is linked via its C-terminus to either the N-terminus of the CD3 Fab or to the hinge region of the Fc portion, and is thus located between the Fc portion and the CD3 Fab of the bispecific antibody.

[0232] In embodiments comprising two BCMA Fabs, the BCMA Fabs are preferably derived from the same antibody and are preferably identical in CDR sequences, variable domain sequences VH and VL, and / or constant domain sequences CH1 and CL. Preferably, the amino acid sequences of the two BCMA Fabs are identical.

[0233] Bispecific antibodies of the invention may also comprise scFvs instead of Fabs. Thus, in some embodiments, the bispecific antibody has any one of the above formats, in which each Fab is replaced with a corresponding scFv.

[0234] The components of the bispecific antibody of the present invention, such as Fab fragments, may be chemically linked by using a suitable linker according to the state of the art. In a preferred embodiment, a (Gly4-Ser1)2 linker is used (Desplancq DK et al., Protein Eng. 1994 Aug;7(8):1027-33 and Mack M. et al., PNAS July 18, 1995 vol.92 no.15 7021-7025). As used herein, "chemically linked" (or "linked") means that the components are linked by a covalent bond. Because the linker is a peptide linker, such covalent linkage is usually achieved by biochemical recombinant means. For example, linkage can be achieved using nucleic acids encoding the VL and / or VH domains of each Fab fragment, the linker, and, if the antibody contains an Fc, an Fc partial chain.

[0235] If a linker is used, the linker may be of sufficient length and sequence to ensure that the first and second domains can each retain their different binding specificities independently of each other.

[0236] Antibody sequence In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody or antigen-binding fragment thereof comprising the CDR3H region of SEQ ID NO: 17 and the CDR3L region of SEQ ID NO: 20 and a combination of CDR1H, CDR2H, CDR1L and CDR2L regions selected from the group consisting of: a) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 23, and the CDR2L region of SEQ ID NO: 24; b) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 25, and the CDR2L region of SEQ ID NO: 26; c) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 27, and the CDR2L region of SEQ ID NO: 28; d) the CDR1H region of SEQ ID NO: 29 and the CDR2H region of SEQ ID NO: 30, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; e) the CDR1H region of SEQ ID NO: 34 and the CDR2H region of SEQ ID NO: 35, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; f) the CDR1H region of SEQ ID NO: 36 and the CDR2H region of SEQ ID NO: 37, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32, and g) The CDR1H region of SEQ ID NO: 15 and the CDR2H region of SEQ ID NO: 16, the CDR1L region of SEQ ID NO: 18, and the CDR2L region of SEQ ID NO: 19.

[0237] In a preferred embodiment, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising a VH region comprising the CDR1H region of SEQ ID NO: 21, the CDR2H region of SEQ ID NO: 22, and the CDR3H region of SEQ ID NO: 17, and the CDR3L region of SEQ ID NO: 20 and a combination of CDR1L and CDR2L regions selected from the group consisting of: i) The CDR1L region of SEQ ID NO: 27 and the CDR2L region of SEQ ID NO: 28. ii) the CDR1L region of SEQ ID NO: 23 and the CDR2L region of SEQ ID NO: 24; or iii) The CDR1L region of SEQ ID NO: 25 and the CDR2L region of SEQ ID NO: 26.

[0238] In particularly preferred embodiments, the multispecific (e.g. bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising a VH region comprising the CDR1H region of SEQ ID NO: 21, the CDR2H region of SEQ ID NO: 22 and the CDR3H region of SEQ ID NO: 17, and a VL region comprising the CDR1L region of SEQ ID NO: 27, the CDR2L region of SEQ ID NO: 28 and the CDR3L region of SEQ ID NO: 20.

[0239] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising a VH and a VL selected from the group consisting of: a) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 12; b) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 13; c) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 14; d) a VH region of SEQ ID NO: 38 and a VL region of SEQ ID NO: 12; e) a VH region of SEQ ID NO: 39 and a VL region of SEQ ID NO: 12; f) a VH region of SEQ ID NO: 40 and a VL region of SEQ ID NO: 12, or g) A VH region of SEQ ID NO: 9 and a VL region of SEQ ID NO: 11.

[0240] In a particularly preferred embodiment, the anti-BCMA antibody or antigen-binding fragment thereof comprises a VH region of SEQ ID NO:10 and a VL region of SEQ ID NO:14.

[0241] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-CD3 antibody or antigen-binding fragment thereof.

[0242] Examples of anti-CD3 antibodies include OKT3, TR66, APA 1 / 1, SP34, CH2527, WT31, 7D6, UCHT-1, Leu-4, BC-3, H2C, HuM291 (vicilizumab), Hu291 (PDL), ChAglyCD3 (otelixumab), hOKT3γ1 (ara-ara) (teplizumab), and NI-0401 (foralumab).

[0243] The first anti-CD3 antibody produced was OKT3 (muromonab-CD3), a murine antibody that binds to the CD3 epsilon domain. Subsequent anti-CD3 antibodies include humanized or human antibodies, and artificial antibodies, such as those containing modified Fc regions.

[0244] Anti-CD3 antibodies may recognize epitopes on a single polypeptide chain, such as APA 1 / 1 or SP34 (Yang SJ, The Journal of Immunology (1986) 137; 1097-1100), or conformational epitopes located on two or more subunits of CD3, such as WT31, 7D6, UCHT-1 (see WO2000041474), and Leu-4. Clinical trials are underway using several anti-CD3 antibodies, including BC-3 (Anasetti et al., Transplantation 54:844(1992)) and H2C (WO2008119567A2). Anti-CD3 antibodies in clinical development include HuM291 (visilizumab) (Norman et al., Transplantation. 2000 Dec 27;70(12):1707-12.), Hu291 (PDL), ChAglyCD3 (Otelixizumab) (H Waldmann), hOKT3γ1(Ala-Ala) (Teplizumab) (J Bluestone and Johnson and Johnson), and (NI-0401) foralumab.

[0245] Any anti-CD3 antibody or antigen-binding fragment thereof may be suitable for use in the multispecific (e.g., bispecific) antibodies of the present invention. For example, the multispecific (e.g., bispecific) antibody may comprise an anti-CD3 antibody selected from OKT3, TR66, APA1 / 1, SP34, CH2527, WT31, 7D6, UCHT-1, Leu-4, BC-3, H2C, HuM291 (vicilizumab), Hu291 (PDL), ChAglyCD3 (otelixumab), hOKT3γ1 (Ala-Ala) (teplizumab), and NI-0401 (foralumab). In some embodiments, the multispecific (e.g., bispecific) antibody of the present invention comprises a humanized SP34 antibody or an antigen-binding fragment thereof.

[0246] In some preferred embodiments, the anti-CD3 antibody or antigen-binding fragment thereof may be derived from SP34 and may have similar sequence and epitope binding properties as antibody SP34.

[0247] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-CD3 antibody, or antigen-binding fragment thereof, comprising a variable domain VH that comprises the heavy chain CDRs of SEQ ID NOs: 1, 2, and 3 as heavy chain CDR1H, CDR2H, and CDR3H, respectively, and a variable domain VL that comprises the light chain CDRs of SEQ ID NOs: 4, 5, and 6 as light chain CDR1L, CDR2L, and CDR3L, respectively. In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-CD3 antibody, or antigen-binding fragment thereof, comprising the variable domains of SEQ ID NO: 7 (VH) and SEQ ID NO: 8 (VL).

[0248] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody or antigen-binding fragment thereof comprising the CDR3H region of SEQ ID NO: 17 and the CDR3L region of SEQ ID NO: 20, and a combination of CDR1H, CDR2H, CDR1L, and CDR2L regions selected from the group consisting of: a) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 23, and the CDR2L region of SEQ ID NO: 24; b) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 25, and the CDR2L region of SEQ ID NO: 26; c) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 27, and the CDR2L region of SEQ ID NO: 28; d) the CDR1H region of SEQ ID NO: 29 and the CDR2H region of SEQ ID NO: 30, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; e) the CDR1H region of SEQ ID NO: 34 and the CDR2H region of SEQ ID NO: 35, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; f) the CDR1H region of SEQ ID NO: 36 and the CDR2H region of SEQ ID NO: 37, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32, and g) the CDR1H region of SEQ ID NO: 15 and the CDR2H region of SEQ ID NO: 16, the CDR1L region of SEQ ID NO: 18, and the CDR2L region of SEQ ID NO: 19, and An anti-CD3 antibody or antigen-binding fragment thereof, comprising a CDR1H region of SEQ ID NO: 1, a CDR2H region of SEQ ID NO: 2, a CDR3H region of SEQ ID NO: 3, a CDR1L region of SEQ ID NO: 4, a CDR2L region of SEQ ID NO: 5, and a CDR3L region of SEQ ID NO: 6.

[0249] In particularly preferred embodiments, the multispecific (e.g., bispecific) antibody comprises: a VH region comprising the CDR1H region of SEQ ID NO: 21, the CDR2H region of SEQ ID NO: 22, and the CDR3H region of SEQ ID NO: 17, and a VL region comprising the CDR1L region of SEQ ID NO: 27, the CDR2L region of SEQ ID NO: 28, and the CDR3L region of SEQ ID NO: 20; an anti-BCMA antibody or antigen-binding fragment thereof; and An anti-CD3 antibody or antigen-binding fragment thereof, comprising a CDR1H region of SEQ ID NO: 1, a CDR2H region of SEQ ID NO: 2, a CDR3H region of SEQ ID NO: 3, a CDR1L region of SEQ ID NO: 4, a CDR2L region of SEQ ID NO: 5, and a CDR3L region of SEQ ID NO: 6. Includes.

[0250] In some embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising a VH and a VL selected from the group consisting of: a) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 12; b) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 13; c) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 14; d) a VH region of SEQ ID NO: 38 and a VL region of SEQ ID NO: 12; e) a VH region of SEQ ID NO: 39 and a VL region of SEQ ID NO: 12; f) a VH region of SEQ ID NO: 40 and a VL region of SEQ ID NO: 12, and An anti-CD3 antibody or antigen-binding fragment thereof, comprising a VH region of SEQ ID NO: 7 and a VL region of SEQ ID NO: 8.

[0251] In particularly preferred embodiments, the multispecific (e.g., bispecific) antibody comprises an anti-BCMA antibody, or antigen-binding fragment thereof, comprising the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 14, and an anti-CD3 antibody, or antigen-binding fragment thereof, comprising the VH region of SEQ ID NO: 7 and the VL region of SEQ ID NO: 8.

[0252] Fc Multispecific antibodies, e.g., bispecific antibodies, of the present invention may or may not have an Fc. In a preferred embodiment, the multispecific antibodies of the present invention comprise an Fc, preferably a human Fc.

[0253] In certain embodiments, the Fc is a variant Fc, e.g., an Fc sequence that has been modified (e.g., by amino acid substitution, deletion, and / or insertion) relative to a parent Fc sequence (e.g., an unmodified Fc polypeptide that is subsequently modified to generate the variant) to provide desirable structural characteristics and / or biological activity.

[0254] Thus, multispecific, e.g., bispecific, antibodies of the invention may comprise an Fc that generally comprises one or more modifications to alter one or more functional properties of the antibody, such as serum half-life, complement fixation, Fc receptor binding, and / or antigen-dependent cellular cytotoxicity. The Fc may be linked to an anti-BCMA fragment and / or an anti-CD3 Fab fragment in the antibodies of the invention.

[0255] The presence of Fc has the advantage of extending the elimination half-life of the antibody. The antibodies, e.g., bispecific antibodies, of the present invention may have an elimination half-life of more than 12 hours, preferably 3 days or more, in mice or cynomolgus monkeys, preferably cynomolgus monkeys. In one embodiment, the antibodies, e.g., bispecific antibodies, of the present invention have an elimination half-life of about 1 to 12 days, allowing for administration at least once or twice a week.

[0256] Decreased effector function Preferably, the bispecific antibodies of the present invention comprise an Fc region (e.g., of the IgG1 subclass) that contains modifications to avoid FcR and C1q binding and minimize ADCC / CDC. This provides the advantage that bispecific antibodies mediate their tumor cell killing ability purely through a potent mechanism of effector cell, e.g., T cell, redirection / activation. Thus, additional mechanisms of action, such as effects on the complement system and on FcR-expressing effector cells, are avoided, reducing the risk of side effects such as infusion-related reactions.

[0257] In a preferred embodiment, the antibody of the invention, eg, a bispecific antibody, comprises an IgG, particularly an IgG1, Fc region comprising the modifications L234A, L235A and P329G (numbering according to EU numbering).

[0258] Heterodimerization The multispecific, e.g., bispecific, antibodies of the invention may be heteromultimeric antibodies, which may contain modifications in regions involved in interactions between antibody chains to promote correct assembly of the antibody.

[0259] For example, a bispecific antibody of the invention may comprise an Fc with one or more modification(s) in the CH2 and CH3 domains to effect Fc heterodimerization. Alternatively or additionally, a bispecific antibody of the invention may comprise modifications in the CH1 and CL regions to promote preferential pairing between the heavy and light chains of the Fab fragment.

[0260] There are many strategies for promoting heterodimerization. These strategies include introducing asymmetric, complementary modifications into each of the two antibody chains so that both chains are compatible with each other and can therefore form heterodimers, but each chain cannot dimerize with itself. Such modifications can include insertions, deletions, conservative and non-conservative substitutions, and rearrangements.

[0261] Heterodimerization can be promoted by introducing charged residues to create favorable electrostatic interactions between the first and second antibody chains. For example, one or more positively charged amino acids can be introduced into the first antibody chain and one or more negatively charged amino acids can be introduced into the corresponding positions of the second antibody chain.

[0262] Alternatively or additionally, heterodimerization may be promoted by introducing steric hindrance between contacting residues, for example, one or more residues with bulky side chains can be introduced into the first antibody chain, and one or more residues that can accommodate large side chains can be introduced into the second antibody chain.

[0263] Alternatively or additionally, heterodimerization can be promoted by introducing one or more modification(s) to hydrophilic and hydrophobic residues at the interface between the chains, such that heterodimer formation is entropically and enthalpically favored over homodimer formation.

[0264] Another strategy to promote heterodimerization is to rearrange parts of antibody chains so that each chain is only compatible with the corresponding rearranged chain. For example, CrossMAb technology is based on cross-linking antibody domains to allow correct chain binding. There are three main formats of CrossMAb: (i) CrossMAbFab, in which VH and VL are swapped and CH1 and CL are swapped; (ii) CrossMAbVH-VL, in which VH and VL are swapped; and (iii) CrossMAbCH1-CL, in which CH1 and CL are swapped (Klein et al., 2016. MABS, 8(6):1010-1020).

[0265] In some embodiments, bispecific antibodies of the invention may comprise swapped VH and VL. In some embodiments, antibodies of the invention, e.g., bispecific antibodies, may comprise swapped CH1 and CL. In some embodiments, antibodies of the invention, e.g., bispecific antibodies, may comprise swapped VH and VL, as well as swapped CH1 and CL.

[0266] In a preferred embodiment, the antibodies of the invention, eg, bispecific antibodies, comprise swapped VH and VL.

[0267] Other approaches to promote heterodimerization include the use of strand exchange engineering domains (SEEDs) (Davis et al., 2010. Protein Eng Des Sel, 23(4);195-202).

[0268] A combination of the above strategies may be used to maximize the efficiency of assembly while minimizing the impact on antibody stability.

[0269] Fc heterodimerization In certain embodiments, multispecific, e.g., bispecific, antibodies of the invention may have a heterodimeric Fc, e.g., they may comprise one heavy chain derived from an anti-BCMA antibody and one heavy chain derived from an anti-CD3 antibody.

[0270] The antibodies of the present invention, e.g., bispecific antibodies, may comprise a heterodimeric Fc comprising one or more modification(s) that promote association of a first CH2 and / or CH3 domain with a second CH2 and / or CH3 domain. In preferred embodiments, the one or more modification(s) promote association of a first CH3 domain with a second CH3 domain, for example, by introducing an asymmetric modification into the CH3 domain. The one or more modification(s) may comprise a modification selected from amino acid insertions, deletions, conservative and non-conservative substitutions and rearrangements, and combinations thereof.

[0271] Generally, the first and second CH3 domains are engineered to be complementary such that each CH3 domain (or the heavy chain containing it) can no longer homodimerize with itself but must heterodimerize with another complementary engineered CH3 domain (such that the first and second CH3 domains heterodimerize and there is no homodimerization between the two first or second CH3 domains).

[0272] Multispecific antibodies, e.g., bispecific antibodies, of the invention may comprise an Fc with "knob-into-holes" modification(s), which are described in detail, with some examples, in, e.g., WO96 / 027011, Ridgway, JB, et al., Protein Eng. 9 (1996) 617-621, Merchant, AM et al., Nat. Biotechnol. 16 (1998) 677-68, and WO98 / 050431.

[0273] In this method, the interaction surfaces of the two CH3 domains are altered to increase heterodimerization of both Fc chains containing these two CH3 domains. One of the two CH3 domains (of the two Fc chains) can be the "knob" and the other can be the "hole."

[0274] Thus, a bispecific antibody of the invention may comprise two CH3 domains, wherein a first CH3 domain of a first Fc chain and a second CH3 domain of a second Fc chain each meet at an interface that comprises the original interface between antibody CH3 domains, where the interface is altered to facilitate antibody formation.

[0275] In one embodiment, (i) the CH3 domain of one Fc chain is modified so that, within the original interface of the CH3 domain of one Fc chain that mates with the original interface of the CH3 domain of the other Fc chain, amino acid residues are replaced with amino acid residues having larger side chains, thereby creating protrusions at the interface of the CH3 domain of one Fc chain and allowing it to locate within the space at the interface of the CH3 domain of the other Fc chain; and ii) Within the original interface of the CH3 domain of one Fc chain, amino acid residues that fit into the original interface of the CH3 domain of the other Fc chain are replaced with amino acid residues having smaller side chains, thereby creating a space within the interface of the CH3 domain of the other Fc chain into which a protrusion within the interface of the CH3 domain of one Fc chain can be positioned, thereby altering the CH3 domain of one Fc chain and allowing the CH3 domain of one Fc chain to be positioned.

[0276] Preferably, the amino acid residue with a larger side chain volume is selected from the group consisting of arginine (R), phenylalanine (F), tyrosine (Y), tryptophan (W).

[0277] In some embodiments the multispecific antibody, such as the bispecific antibody, of the invention comprises a first CH3 domain comprising modification(s) at positions T366, L368 and Y407, such as T366S, L368A and Y407V (numbering according to EU numbering).

[0278] In some embodiments, the multispecific antibody, such as the bispecific antibody, of the invention comprises a second CH3 domain comprising a modification at position T366 (a "knob modification"), such as T366W (numbering according to EU numbering).

[0279] In a particularly preferred embodiment, the multispecific, such as bispecific, antibody of the invention comprises a first CH3 domain comprising the modifications T366S, L368A and Y407V, or conservative substitutions thereof, and a second CH3 domain comprising the modification T366W, or conservative substitutions thereof (numbering according to EU numbering).

[0280] In one embodiment a multispecific antibody, such as a bispecific antibody, of the invention comprises a first CH3 domain comprising a modification described in Table 12 and a second CH3 domain comprising a modification described in Table 12. [Table 12]

[0281] Other techniques of CH3 modification to effect heterodimerization are contemplated as alternatives of the present invention and are described, for example, in WO96 / 27011, WO98 / 050431, EP1870459, WO2007 / 110205, WO2007 / 147901, WO2009 / 089004, WO2010 / 129304, WO2011 / 90754, WO2011 / 143545, WO2012 / 058768, WO2013 / 157954, WO2013 / 157953 and WO2013 / 096291.

[0282] In one embodiment, the bispecific antibody according to the invention is of the IgG2 isotype and the heterodimerization approach described in WO2010 / 129304 can be used.

[0283] Other Fc modifications In some embodiments, the bispecific antibody of the present invention may comprise an Fc in which both CH3 domains have been modified by introducing a cysteine ​​(C) as an amino acid at the corresponding position in each CH3 domain so that disulfide bridges can form between the two CH3 domains. The cysteine ​​may be introduced at position 349 in one CH3 domain and at position 354 in the other CH3 domain (EU numbering).

[0284] Preferably, the introduced cysteine ​​at position 354 is in the first CH3 domain and the introduced cysteine ​​at position 349 is in the second CH3 domain (numbering according to EU numbering).

[0285] The Fc may contain modifications such as D356E, L358M, N384S, K392N, V397M and V422I (numbered according to EU numbering). Preferably, both CH3 domains contain D356E and L358M (numbered according to EU numbering).

[0286] Heterodimerization of light and heavy chains In the multispecific antibodies, e.g., bispecific antibodies, of the present invention, one or more of the immunoglobulin heavy and light chains may contain one or more modification(s), e.g., amino acid modifications, that can promote preferential pairing of a specific heavy chain with a specific light chain when the heavy and light chains are co-expressed or co-produced. Such modifications can provide significantly improved production / purification without altering biological properties such as binding to BCMA. In particular, the introduction of one or more modifications, such as amino acid substitutions, can significantly reduce light chain mispairing and the formation of by-products during production, thereby increasing yield and facilitating purification.

[0287] The amino acid substitutions may be for oppositely charged amino acids (eg, at the CH1 / CL interface) to reduce mispairing in the light chain, eg, reducing Bence-Jones type by-products.

[0288] In preferred embodiments, the one or more modification(s) that support heterodimerization of the light and heavy chains are amino acid modifications in the light and heavy chains outside of the CDRs.

[0289] The one or more modification(s) may be present in the anti-BCMA antibody or antigen-binding fragment thereof. Alternatively, the one or more modification(s) may be present in the anti-CD3 antibody or antigen-binding fragment thereof. In a preferred embodiment, the one or more modification(s) are present in the anti-BCMA antibody or antigen-binding fragment thereof.

[0290] In certain embodiments, a multispecific, e.g., bispecific, antibody of the invention comprises an immunoglobulin heavy chain comprising a CH1 domain with the amino acid modifications K147E / D and K213E / D (numbering according to EU numbering), and a corresponding immunoglobulin light chain comprising a CL domain with the amino acid modifications E123K / R / H and Q124K / R / H (numbering according to Kabat). Preferably, the CH1 domain comprises the amino acid modifications K147E and K213E (numbering according to EU numbering) or conservative substitutions thereof, and the corresponding CL domain comprises the amino acid modifications E123R and Q124K or conservative substitutions thereof (numbering according to Kabat). Such multispecific, e.g., bispecific, antibodies can be produced in high yield and easily purified.

[0291] In one embodiment, the amino acid modifications set forth in Table 13 may be present in a BCMA antibody or a CD3 antibody.

[0292] In one embodiment, the bispecific antibody of the invention is bivalent and comprises one anti-BCMA antibody, or antigen-binding fragment thereof, and one anti-CD3 antibody, or antigen-binding fragment thereof ("1+1" format), wherein (a) a BCMA antibody or antigen-binding fragment thereof (e.g., a BCMA Fab) comprising a CH1 domain with an amino acid modification listed in Table 13 and a corresponding CL domain with an amino acid modification listed in Table 13; or (b) A CD3 antibody or antigen-binding fragment thereof (e.g., CD3 Fab) comprises a CH1 domain having an amino acid modification listed in Table 13 and a corresponding CL domain having an amino acid modification listed in Table 13.

[0293] In one embodiment, the bispecific antibody of the invention is trivalent and comprises two anti-BCMA antibodies or antigen-binding fragments thereof and one anti-CD3 antibody or antigen-binding fragment thereof ("2+1" format), wherein: (a) one or both BCMA antibodies or antigen-binding fragments thereof (e.g., BCMA Fab) comprise a CH1 domain with an amino acid modification listed in Table 13 and a corresponding CL domain with an amino acid modification listed in Table 13; or (b) A CD3 antibody (eg, a CD3 Fab) comprises a CH1 domain with an amino acid modification listed in Table 13 and a corresponding CL domain with an amino acid modification listed in Table 13.

[0294] In particular, each BCMA antibody (e.g., BCMA Fab) may comprise a CH1 domain having an amino acid modification as set forth in Table 13, and a corresponding CL domain having an amino acid modification as set forth in Table 13.

[0295] [Table 13]

[0296] In a preferred embodiment, a multispecific antibody, such as a bispecific antibody, of the invention comprises a modification listed in Table 13 in combination with a modification listed in Table 12. Thus, in one embodiment, a bispecific antibody of the invention is bivalent and comprises the following: (a) one anti-BCMA antibody or antigen-binding fragment thereof and one anti-CD3 antibody or antigen-binding fragment thereof ("1+1" format), wherein: (i) the BCMA antibody or antigen-binding fragment thereof (e.g., BCMA Fab) comprises a CH1 domain comprising the amino acid modifications K147E and K213E, and a corresponding CL domain comprising the amino acid modifications E123R and Q124K (i.e., a modification described in Table 13), or (ii) the CD3 antibody or antigen-binding fragment thereof (e.g., CD3 Fab) comprises a CH1 domain comprising the amino acid modifications K147E and K213E, and a corresponding CL domain comprising the amino acid modifications E123R and Q124K (i.e., a modification described in Table 13); and (b) a first CH3 domain comprising the modifications T366S, L368A and Y407V, and a second CH3 domain comprising the modification T366W (i.e., the modifications described in Table 12); Includes.

[0297] In one embodiment, the bispecific antibody of the invention is trivalent and has the following: (a) two anti-BCMA antibodies or antigen-binding fragments thereof, and one anti-CD3 antibody or antigen-binding fragment thereof ("2+1" format), wherein (i) one or both BCMA antibodies or antigen-binding fragments thereof (e.g., BCMA Fab) comprise a CH1 domain comprising the amino acid modifications K147E and K213E, and a corresponding CL domain comprising the amino acid modifications E123R and Q124K (i.e., a modification described in Table 13), or (ii) a CD3 antibody or antigen-binding fragment thereof (e.g., CD3 Fab) comprises a CH1 domain comprising the amino acid modifications K147E and K213E, and a corresponding CL domain comprising the amino acid modifications E123R and Q124K (i.e., a modification described in Table 13); and (b) a first CH3 domain comprising the modifications T366S, L368A and Y407V, and a second CH3 domain comprising the modification T366W (i.e., the modifications described in Table 12); Includes.

[0298] In particular, each BCMA antibody (e.g., BCMA Fab) may comprise a CH1 domain with an amino acid modification as set forth in Table 13 and a corresponding CL domain with an amino acid modification as set forth in Table 13. In a preferred embodiment, a first Fc chain is attached at the N-terminus of the Fc to the C-terminus of the first anti-BCMA antibody, and a second Fc chain is attached at the N-terminus of the Fc to the C-terminus of the anti-CD3 antibody.

[0299] Multispecific antibodies, for example bispecific antibodies, of the present invention may further comprise an amino acid substitution at position 49 of the VL region selected from the group consisting of tyrosine (Y), glutamic acid (E), serine (S) and histidine (H), and / or an amino acid substitution at position 74 of the VL region with threonine (T) or alanine (A).

[0300] CrossMAb The multispecific antibodies, e.g., bispecific antibodies, of the present invention may include CrossMAb technology. CrossMAb technology is based on cross-linking antibody domains to allow correct chain binding. This is used to facilitate the formation of multispecific antibodies. There are three main formats of CrossMAb: (i) CrossMAbFab, in which VH and VL, CH1 and CL are swapped; (ii) CrossMAbVH-VL, in which VH and VL are swapped; and (iii) CrossMAbCH1-CL, in which CH1 and CL are swapped (Clain et al. 2016. mabs, 8(6):1010-1020).

[0301] CrossMAb technology is known in the art. Bispecific antibodies in which the variable domains VL and VH or the constant domains CL and CH1 are exchanged with each other are described in WO2009080251 and WO2009080252.

[0302] In one or more of the antibodies or antigen-binding fragments within a multispecific antibody, e.g., a bispecific antibody, of the invention, the variable domains VL and VH, or the constant domains CL and CH1, may be substituted for one another. In some embodiments, an antibody, e.g., a bispecific antibody, of the invention may comprise an exchange of VH and VL, and an exchange of CH1 and CL. Thus, a multispecific antibody, e.g., a bispecific antibody, of the invention may comprise a crossover light chain and a crossover heavy chain. As used herein, a "crossover light chain" is a light chain that may comprise VH-CL, VL-CH1, or VH-CH1. As used herein, a "crossover heavy chain" is a heavy chain that may comprise VL-CH1, VH-CL, or VL-CL.

[0303] In some embodiments, a multispecific antibody, e.g., a bispecific antibody, is provided comprising an anti-BCMA antibody, or antigen-binding fragment thereof, and an anti-CD3 antibody, or antigen-binding fragment thereof, of the present invention, wherein the multispecific antibody, e.g., the bispecific antibody, is (a) the light and heavy chains of an antibody that specifically binds to CD3; and (b) Light and heavy chains of an antibody that specifically binds to BCMA wherein the variable domains VL and VH and / or the constant domains CL and CH1 are substituted for each other in (i) an anti-BCMA antibody; and / or (ii) an anti-CD3 antibody.

[0304] In some embodiments, the variable domains VL and VH, or the constant domains CL and CH1, of an anti-CD3 antibody or antigen-binding fragment thereof are substituted for each other. More preferably, the variable domains VL and VH of an anti-CD3 antibody or antigen-binding fragment thereof are substituted for each other.

[0305] In embodiments where the bispecific antibody in a 1+1 format has the formats: CD3 Fab - BCMA Fab (i.e., when Fc is absent); Fc - CD3 Fab - BCMA Fab; Fc- BCMA Fab - CD3 Fab; or BCMA Fab - Fc - CD3 Fab, the bispecific antibody may be, for example, a CrossMAb. Fab , CrossMAb VH-VL or CrossMAb CH1-CL The BCMA Fab may be in a CrossMAb format, such as CrossMAb Fab , CrossMAb VH-VL or CrossMAb CH1-CL Alternatively, the CD3 Fab may be in a CrossMAb format, e.g., CrossMAb Fab , CrossMAb VH-VL or CrossMAb CH1-CL In a preferred embodiment, the CD3 Fab of the bispecific antibody may have the following structure: CrossMAb VH-VL Includes format.

[0306] It is particularly preferred that bispecific antibodies of the invention having a 2+1 format comprise CrossMAb technology. Thus, in embodiments where a trivalent bispecific antibody in a 2+1 format has the formats: CD3 Fab - BCMA Fab - BCMA Fab; BCMA Fab - CD3 Fab - BCMA Fab (i.e., when Fc is absent); BCMA Fab - Fc - CD3 Fab - BCMA Fab; BCMA Fab - Fc - BCMA Fab - CD3 Fab; or CD3 Fab - Fc - BCMA Fab - BCMA Fab, the bispecific antibody can be, for example, a CrossMAb. Fab , CrossMAb VH-VL or CrossMAb CH1-CL The BCMA Fab may be in a CrossMAb format, such as CrossMAb Fab, CrossMAb VH-VL or CrossMAb CH1-CL Alternatively, the CD3 Fab may be in a CrossMAb format, e.g., CrossMAb Fab , CrossMAb VH-VL or CrossMAb CH1-CL In a preferred embodiment, the CD3 Fab of the bispecific antibody may have the following structure: CrossMAb VH-VL Includes format.

[0307] In some embodiments, bispecific antibodies of the invention having a 1+1 format do not comprise CrossMAb technology, i.e. neither the anti-BCMA antibody nor the anti-CD3 antibody have the variable domains VL and VH or the constant domains CL and CH1 substituted for each other.

[0308] Exemplary Embodiments Exemplary embodiments are depicted in FIGS.

[0309] In one embodiment, the bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion of the format BCMA Fab-Fc-CD3 Fab. The anti-BCMA Fab fragment comprises the amino acid modifications shown in Table 13. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. This embodiment is shown in Figure 1A.

[0310] In one embodiment, the bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion of the format BCMA Fab-Fc-CD3 Fab. The anti-CD3 Fab fragment comprises (a) a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising the variable domain VH and the constant domain CL, and the heavy chain is a crossover heavy chain comprising the variable domain VL and the constant domain CH1, and (b) comprises an amino acid modification as set forth in Table 13. This embodiment is shown in Figure 1B.

[0311] In one embodiment, the bispecific antibody of the invention is a trivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, two Fab fragments of an anti-BCMA antibody, and one Fc portion in the format BCMA Fab - Fc - CD3 Fab - BCMA Fab. Each anti-BCMA Fab fragment comprises the amino acid modifications shown in Table 13. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. This embodiment is shown in Figure 2A.

[0312] In one embodiment, the bispecific antibody of the invention is a trivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, two Fab fragments of an anti-BCMA antibody, and one Fc portion in the format BCMA Fab - Fc - CD3 Fab - BCMA Fab. The anti-CD3 Fab fragment comprises (a) a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1, and (b) an amino acid modification as set forth in Table 13. This embodiment is shown in Figure 2B.

[0313] In one embodiment, the bispecific antibody of the invention is a trivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, two Fab fragments of an anti-BCMA antibody, and one Fc portion in the format BCMA Fab - Fc - BCMA Fab - CD3 Fab. Each anti-BCMA Fab fragment comprises the amino acid modifications shown in Table 13. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. This embodiment is shown in Figure 2C.

[0314] In one embodiment, a bispecific antibody of the invention is a trivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, two Fab fragments of an anti-BCMA antibody, and one Fc portion in the format BCMA Fab - Fc - BCMA Fab - CD3 Fab. The anti-CD3 Fab fragment comprises (a) a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1, and (b) an amino acid modification as set forth in Table 13. This embodiment is shown in Figure 2D.

[0315] In one embodiment, the bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion in the format Fc - CD3 Fab - BCMA Fab. The anti-BCMA Fab fragment comprises the amino acid modifications shown in Table 13. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. This embodiment is shown in Figure 3A.

[0316] In one embodiment, a bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion in the format Fc - CD3 Fab - BCMA Fab. The anti-CD3 Fab fragment comprises (a) a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising the variable domain VH and the constant domain CL, and the heavy chain is a crossover heavy chain comprising the variable domain VL and the constant domain CH1, and (b) an amino acid modification as set forth in Table 13. This embodiment is shown in Figure 3B.

[0317] In one embodiment, the bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion in the format Fc - BCMA Fab - CD3 Fab. The anti-BCMA Fab fragment comprises the amino acid modifications shown in Table 13. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. This embodiment is shown in Figure 3C.

[0318] In one embodiment, a bispecific antibody of the invention is a bivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, one Fab fragment of an anti-BCMA antibody, and one Fc portion in the format Fc - BCMA Fab - CD3 Fab. The anti-CD3 Fab fragment comprises (a) a light chain and a heavy chain, wherein the light chain is a crossover light chain comprising the variable domain VH and the constant domain CL, and the heavy chain is a crossover heavy chain comprising the variable domain VL and the constant domain CH1, and (b) comprises an amino acid modification as set forth in Table 13. This embodiment is shown in Figure 3D.

[0319] In one embodiment, the antibody illustrated in FIG. 2 further comprises a modification defined in Table 12.

[0320] In one embodiment, the bispecific antibody of the invention is a trivalent bispecific antibody comprising one Fab fragment of an anti-CD3 antibody, two Fab fragments of an anti-BCMA antibody, and one Fc portion in the format BCMA Fab - Fc - CD3 Fab - BCMA Fab. The anti-CD3 Fab fragment comprises a light chain and a heavy chain, where the light chain is a crossover light chain comprising a variable domain VH and a constant domain CL, and the heavy chain is a crossover heavy chain comprising a variable domain VL and a constant domain CH1. Each anti-BCMA Fab fragment comprises a light chain and a heavy chain, where the heavy chain comprises a CH1 domain comprising the amino acid modifications K147E and K213E (numbering according to EU numbering), and the light chain comprises a corresponding CL domain comprising the amino acid modifications E123R and Q124K (numbering according to Kabat) (i.e., the modifications described in Table 13). The Fc portion comprises a first Fc chain and a second Fc chain, wherein the first Fc chain comprises a first constant domain CH2 and a first constant domain CH3, and the second Fc chain comprises a second constant domain CH2 and a second constant domain CH3. The first Fc chain is linked at its N-terminus to the C-terminus of a first anti-BCMA Fab, and the second Fc chain is linked at its N-terminus to the C-terminus of an anti-CD3 Fab. The first CH3 domain comprises the modifications T366S, L368A, and Y407V ("hole modifications"), and the second CH3 domain comprises the modification T366W ("knob modification") (numbering according to EU numbering) (i.e., modifications described in Table 12). Additionally, both Fc chains further comprise the modifications L234A, L235A and P329G, and optionally D356E and L358M (numbered according to EU numbering). Optionally, the first CH3 domain may further comprise the amino acid modification S354C, and the second CH3 domain may further comprise the amino acid modification Y349C (numbered according to EU numbering), such that a disulfide bridge between both CH3 domains is formed.

[0321] In one embodiment the anti-BCMA Fab fragment comprises the CDR3H region of SEQ ID NO: 17 and the CDR3L region of SEQ ID NO: 20, and the following: a) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 23, and the CDR2L region of SEQ ID NO: 24; b) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 25, and the CDR2L region of SEQ ID NO: 26; c) the CDR1H region of SEQ ID NO: 21 and the CDR2H region of SEQ ID NO: 22, the CDR1L region of SEQ ID NO: 27, and the CDR2L region of SEQ ID NO: 28; d) a CDR1H region of SEQ ID NO: 29 and a CDR2H region of SEQ ID NO: 30, a CDR1L region of SEQ ID NO: 31, and a CDR2L region of SEQ ID NO: 32; e) the CDR1H region of SEQ ID NO: 34 and the CDR2H region of SEQ ID NO: 35, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32; f) the CDR1H region of SEQ ID NO: 36 and the CDR2H region of SEQ ID NO: 37, the CDR1L region of SEQ ID NO: 31, and the CDR2L region of SEQ ID NO: 32, and g) the CDR1H region of SEQ ID NO: 15 and the CDR2H region of SEQ ID NO: 16, the CDR1L region of SEQ ID NO: 18, and the CDR2L region of SEQ ID NO: 19 and the anti-CD3 Fab fragment comprises a CDR1H region of SEQ ID NO: 1, a CDR2H region of SEQ ID NO: 2, a CDR3H region of SEQ ID NO: 3, a CDR1L region of SEQ ID NO: 4, a CDR2L region of SEQ ID NO: 5 and a CDR3L region of SEQ ID NO: 6.

[0322] In one embodiment the anti-BCMA Fab fragment comprises: a) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 12; b) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 13; c) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 14; d) a VH region of SEQ ID NO: 38 and a VL region of SEQ ID NO: 12; e) a VH region of SEQ ID NO: 39 and a VL region of SEQ ID NO: 12; f) a VH region of SEQ ID NO: 40 and a VL region of SEQ ID NO: 12; or g) the VH region of SEQ ID NO: 9 and the VL region of SEQ ID NO: 11 and the anti-CD3 Fab fragment comprises a VH region of SEQ ID NO:7 and a VL region of SEQ ID NO:8.

[0323] In one embodiment, a bispecific antibody of the invention comprises the following SEQ ID NOs (listed in Tables 14A and 15B below): 83A10-TCBcv: 45, 46, 47(x2), 48 (Figure 2A) 21-TCBcv: 48, 49, 50, 51(x2) (Figure 2A) 22-TCBcv: 48, 52, 53, 54 (x2) (Figure 2A) 42-TCBcv:48, 55, 56, 57(x2) (Fig. 2A).

[0324] As used herein, the term "83A10-TCBcv" refers to a bispecific antibody that specifically binds to BCMA and CD3, as defined by its heavy and light chain combinations of SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47(2x), and SEQ ID NO: 48, as shown in FIG. 2A, and as described in EP14179705.

[0325] The terms "21-TCBcv, 22-TCBcv, 42-TCBcv" as used herein refer to the respective bispecific antibodies Mab21, defined by the combination of its heavy and light chains set forth in SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51 (2x), Mab 22, defined by the combination of its heavy and light chains set forth in SEQ ID NO: 48, SEQ ID NO: 52, SEQ ID NO: 53, and SEQ ID NO: 54 (2x), and Mab42, defined by the combination of its heavy and light chains set forth in SEQ ID NO: 48, SEQ ID NO: 55, SEQ ID NO: 56, and SEQ ID NO: 57 (2x), as shown in FIG. 2A and described in WO2017 / 021450.

[0326] In a preferred embodiment, the bispecific antibody is 42-TCBcv.

[0327] Pharmaceutical Composition The multispecific, e.g., bispecific, antibodies of the invention can be administered to a patient as a pharmaceutical composition. Accordingly, the invention also provides pharmaceutical compositions comprising the multispecific, e.g., bispecific, antibodies of the invention and a pharmaceutically acceptable excipient.

[0328] As used herein, the term "pharmaceutically acceptable" means approved by a regulatory agency of the federal or state government or listed in the United States Pharmacopoeia, the European Pharmacopoeia, or other generally recognized pharmacopoeias for use in animals, and more particularly in humans.

[0329] Examples of suitable excipients include one or more of water, saline, phosphate-buffered saline, dextrose, glycerol, ethanol, etc., and any combination thereof. It is often preferable to include an isotonicity agent, such as a sugar, a polyhydric alcohol, or sodium chloride, in the composition. Particularly relevant examples of suitable excipients include: (1) Dulbecco's phosphate-buffered saline, pH about 7.4, with or without about 1 mg / mL to 25 mg / mL human serum albumin; (2) 0.9% saline (0.9% w / v sodium chloride (NaCl)); and (3) 5% (w / v) dextrose, which may also contain an antioxidant, such as tryptamine, and a stabilizer, such as Tween 20®.

[0330] One of skill in the art will appreciate that the appropriate choice of excipient(s) for use with a multispecific antibody, e.g., a bispecific antibody, of the invention will depend on the desired properties of the pharmaceutical composition.

[0331] Monotherapy and combination therapy In some embodiments, the treatment comprises administering a multispecific antibody, e.g., a bispecific antibody, of the invention to the patient as monotherapy.

[0332] In some embodiments, the treatment comprises administering a multispecific antibody, e.g., a bispecific antibody, of the invention to a patient as a combination therapy, where the combination therapy comprises administering a multispecific antibody, e.g., a bispecific antibody, of the invention and one or more additional therapeutic agents. The term "combination therapy" is meant to encompass the administration of selected therapeutic agents to a single patient and is intended to include treatment in which the therapeutic agents are administered by the same or different routes of administration or at the same or different times.

[0333] In certain embodiments, the one or more additional therapeutic agents are selected from the group consisting of thalidomide and its immunotherapeutic derivatives, anti-CD38 antibodies, anti-PD-1 antibodies, anti-PD-L1 antibodies, gamma secretase inhibitors (GSIs), anti-BCMA antibody drug conjugates, and anti-BCMA CAR T-cell therapy.

[0334] The term "anti-CD38 antibody" as used herein refers to an antibody that specifically binds to human CD38. In an embodiment of the present invention, the anti-CD38 antibody is daratumumab (US20150246123). In an embodiment of the present invention, the anti-CD38 antibody is isatuximab (SAR650984, US887899). In an embodiment of the present invention, the anti-CD38 antibody is MOR202 (WO2012041800). In an embodiment of the present invention, the anti-CD38 antibody is Ab79 (US8362211). In an embodiment of the present invention, the anti-CD38 antibody is Ab19 (US8362211). The dosage of such anti-CD38 antibodies is determined according to the state of the art and is described in the respective prescribing information. For example, the dosage of daratumumab is typically 16 mg / kg (www.ema.europa.eu).

[0335] The term "thalidomide compound" or "thalidomide and immunotherapeutic derivatives" as used herein relates to 2-(2,6-dioxopiperidin-3-yl)-2,3-dihydro-1H-isoindole-1,3-dione and its immunotherapeutic derivatives. In an embodiment of the present invention, the thalidomide compound is selected from the group consisting of, but not limited to, thalidomide (CAS Registry Number 50-35-1), lenalidomide (CAS Registry Number 191732-72-6), pomalidomide (CAS Registry Number 1971-19-8), CC122 (CAS Registry Number 1398053-45-6), and CC-220 (CAS Registry Number 1323403-33-3), and their respective salts (preferably 1:1 HCl salts). The chemical formula of CC-122 is 2,6-piperidinedione, 3-(5-amino-2-methyl-4-oxo-3(4H-quinazolinyl), hydrochloride (1:1), and that of CC-220 is 2,6-piperidinedione, 3-[1,3-dihydro-4-[(4-morpholinylmethyl)phenyl]methoxy]-1-oxo-2H-isoindol-2-yl), (3S)-, hydrochloride (1:1). Methods for preparing CC-220 are described, for example, in US20110196150, the entire contents of which are incorporated herein by reference.

[0336] The dosage of the thalidomide compound is determined according to the state of the art and is described in the respective formulation examples. For example, the dosage of Revlimid® (lenalidomide) is typically 25 mg administered orally once daily on days 1-21 of a 28-day cycle (www.revlimid.com), and the dosage of POMALYST® (pomalidomide) for the treatment of multiple myeloma is typically 4 mg administered orally daily on days 1-21 of a 28-day cycle (www.celgene.com). In one embodiment, 3-(5-amino-2-methyl-4-oxo-4H-quinazolin-3-yl)-piperidine-2,6-dione is administered in an amount of about 5 to about 50 mg per day.

[0337] In one embodiment, CC-122 and CC-220 are administered in an amount of about 5 to about 25 mg per day. In another embodiment, CC-122 and CC-220 are administered in an amount of about 5 mg, 10 mg, 15 mg, 25 mg, 30 mg, or 50 mg per day. In another embodiment, 10 mg or 25 mg of CC-122 and CC-220 are administered per day. In one embodiment, CC-122 and CC-220 are administered twice daily.

[0338] The term "anti-PD-1 antibody" as used herein refers to an antibody that specifically binds to human PD-1. Such antibodies are described, for example, in WO2015026634 (MK-3475, pembrolizumab), US7521051, US8008449, and US8354509. Pembrolizumab (Keytruda®, MK-3475) is also described in WO2009 / 114335, Poole, RM Drugs (2014) 74: 1973; Seiwert, T., et al., J. Clin. Oncol. 32,5s (suppl;abstr 6011). In an embodiment of the present invention, the PD-1 antibody is MK-3475 (WHO Drug Information, Vol. 27, No. 2, pages 161-162 (2013)), and the amino acid sequence of pembrolizumab, including the heavy and light chain amino acid sequences shown in Figure 6 of WO2015026634, is described in WO2008156712 (light chain CDR SEQ ID NOS: 15, 16, and 17 and heavy chain CDR SEQ ID NOS: 18, 19, and 20). In an embodiment of the present invention, the PD-1 antibody is nivolumab (BMS-936558, MDX 1106; WHO Drug Information, Vol. 27, No. 1, pages 68-69 (2013), ), WO2006 / 121, the amino acid sequence shown in WO2015026634). In an embodiment of the invention the PD-1 antibody is pidilizumab (CT-011, also known as hBAT or hBAT-1; amino acid sequence WO2003 / 099196; WO2009 / 101611, Fried I. et al.; Neuro Oncol (2014) 16 (suppl 5): v111-v112.). In an embodiment of the invention the PD-1 antibody is MEDI-0680 (AMP-514, WO2010 / 027423, WO2010 / 027827, WO2010 / 027828, Hamid O. et al.; J Clin Oncol 33, 2015 (suppl; abstr TPS3087)).In an embodiment of the invention, the PD-1 antibody is PDR001 (Naing A. et al.; J Clin Oncol 34, 2016 (suppl; abstr 3060)). In an embodiment of the invention, the PD-1 antibody is REGN2810 (Papadopoulos KP et al.; J Clin Oncol 34, 2016 (suppl; abstr 3024)). In an embodiment of the invention, the PD-1 antibody is ramulizumab (WO2008 / 156712). In an embodiment of the invention, the PD-1 antibody is h409A11, h409A16, or h409A17, as described in WO2008 / 156712. The dosage of such anti-PD-1 antibodies is determined according to the level of skill in the art and is described in the respective formulation examples. For example, Keytruda® is typically administered at a concentration of 2 mg / kg body weight every three weeks (http: / / ec.europa.eu / health / documents).

[0339] As used herein, the term "anti-PD-L1 antibody" refers to an antibody that specifically binds to human PD-L1. Such antibodies are described, for example, in WO2015026634, WO2013 / 019906, WO2010 / 077634, and US8383796. In an embodiment of the invention, the PD-L1 antibody is MPDL3280A (atezolizumab, YW243.55.S70, WO2010 / 077634, McDermott DF. Et al., JCO March 10, 2016 vol.34 no.8 833-842). In an embodiment of the invention, the PD-L1 antibody is MDX-1105 (BMS-936559, WO2007 / 005874, Patrick A. Ott PA et al., DOI: 10.1158 / 1078-0432, Clinical Cancer Research-13-0143). In an embodiment of the invention, the PD-L1 antibody is MEDI4736 (durvalumab, WO2016 / 040238 Gilbert J. et al., Journal for ImmunoTherapy of Cancer 20153(Suppl 2):P152). In an embodiment of the invention, the PD-L1 antibody is MSB001071 8C (avelumab, Disis ML. et al., Journal of Clinical Oncology, Vol 33, No 15_suppl (May 20 Supplement), 2015:5509). In an embodiment of the invention, the PD-L1 antibody is an anti-PD-L1 antibody comprising the VH sequence of SEQ ID NO: 16 and the VL sequence of SEQ ID NO: 17 as described in WO2016007235. The dosage of such anti-PD-L1 antibodies will be determined according to the state of the art and is described in the respective formulation examples. For example, atezolizumab is typically administered as a 60-minute intravenous infusion at a concentration of 1200 mg every three weeks (www.accessdata.fda.gov).

[0340] As used herein, the term "gamma secretase" refers to any protein or protein complex that exhibits gamma secretase activity, including binding to a substrate having a gamma secretase cleavage sequence and catalyzing cleavage of the gamma secretase cleavage sequence at the gamma secretase cleavage site to generate a substrate cleavage product. In one embodiment, the gamma secretase is a protein complex that includes one or more of the following subunits: presenilin, nicastrin, gamma secretase subunit APH-1, and gamma secretase subunit PEN-2.

[0341] As used herein, the term "gamma secretase inhibitor" or "GSI" refers to any molecule capable of inhibiting or reducing the expression and / or function of gamma secretase. In certain embodiments, the GSI reduces the expression and / or function of a subunit of gamma secretase (e.g., presenilin, nicastrin, APH-1, or PEN-2). Any form of a "gamma secretase inhibitor," such as a salt, co-crystal, crystalline form, prodrug, etc., is included within the term. In certain embodiments, the GSI is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid.

[0342] The above-described embodiments should be understood as illustrative examples. Additional embodiments are contemplated. It is understood that any feature described in connection with any one embodiment may be used alone or in combination with other described features, and may also be used in combination with any one or more other features of the embodiments or any other combination of embodiments. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined in the appended claims.

[0343] Other examples and variations of the antibodies and methods described herein may be apparent to those of skill in the art. Other examples and variations are within the scope of the invention, as defined in the appended claims.

[0344] All documents cited herein are hereby incorporated by reference in their entirety, including all data, tables, figures, and text presented in the cited documents.

[0345] [Table 14] [Table 15] [Table 16] [Table 17] [Table 18] [Table 19] [Table 20] [Table 21] [Table 22]

[0346] [Table 23]

[0347] [Table 24]

[0348] [Table 25] [Example]

[0349] Example Example 1: Clinical Trial of CC-93269 in Relapsed / Refractory Multiple Myeloma (RRMM): Cohorts 1-7 This trial enrolled 19 patients with RRMM who had not received three or more prior BCMA-directed therapies, including autologous stem cell transplantation, allogeneic stem cell transplantation, lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab (DARA). All patients had MM that was refractory to their last treatment strategy.

[0350] CC-93269 (42-TCBcv), a bispecific antibody that binds bivalently to BCMA and monovalently to CD3, was administered intravenously over 2 hours in 28-day cycles on days 1, 8, 15, and 22 in cycles 1–3, on days 1 and 15 in cycles 4–6, and on day 1 in cycles 7 and beyond. Fourteen patients received fixed doses of 0.15 mg (Cohort 1, n=1), 0.5 mg (Cohort 2, n=1), 1.5 mg (Cohort 3, n=1), 3 mg (Cohort 4, n=4), 6 mg (Cohort 5, n=3), or 10 mg (Cohort 6, n=4) at the appropriate intervals. Five patients received the 6 mg dose starting on day 1 of cycle 1 and the 10 mg dose starting on day 8 of cycle 1 (Cohort 7, n=5).

[0351] Efficacy: Responses were assessed at each cycle starting on day 1 of cycle 2 and at the end of treatment using the International Myeloma Working Group (IMWG) Unified Response Criteria (Rajkumar, 2011a; Kumar, 2016). Minimal residual disease (MRD) was assessed by EuroFlow assessment and, when available, by next-generation sequencing (NGS). MRD negativity was defined as >10 nucleated cells. 5 Only cases where a minimum sensitivity of less than one tumor cell per sample was achieved were reported.

[0352] Of the 12 patients (Cohorts 5-7) who received CC-93269 at 6 mg or higher, 10 achieved a partial response (PR) or better (overall response rate; 83.3%), including 7 patients who achieved a very good partial response (VGPR) or better, and 4 patients who achieved a stringent complete response (SCR); 9 patients (75.0%) were MRD-negative (Table 16). The median time to response was 4.2 weeks (range 4.0-13.1). These data suggest that doses of CC-93269 at 6 mg or higher are clinically effective.

[0353] Additionally, four patients in Cohort 4 failed to respond to continuous 3 mg dosing (Table 16), suggesting insufficient clinical activity at this dose.

[0354] Pharmacokinetic (PK) data at doses 6 mg and above demonstrated significantly increased exposure after multiple doses of CC-93269, suggesting significant target-mediated drug disposition (TMDD) and clearance of BCMA-positive myeloma cells after the first dose, a phenomenon not observed with the 3 mg dose. These data suggest that the 3 mg dose provides an additional margin of safety without target saturation for the majority of subjects.

[0355] [Table 26]

[0356] Safety: To prevent CRS, dexamethasone (maximum 20 mg intravenous administration or equivalent) was administered at the initial dose, with the dose increased to 6 mg or more. Cohorts 1-4 did not receive dexamethasone as premedication.

[0357] Patients were monitored for clinical symptoms and signs related to CRS (Lee, 2014), and CRS events were graded and treated according to the common CTCAE CRS grading scale (Lee, 2015).

[0358] Continuous administration of CC-93269 at ≤3 mg was well tolerated, despite the absence of CRS prophylaxis at this dose. A maximum of Grade 1 cytokine release syndrome was observed at fixed doses of CC-93269 at ≤3 mg (Figure 4).

[0359] In Cohort 6, which received sequential doses of 6 mg of CC-93269, the maximum grade 2 CRS was observed, with all CRS events occurring in Cycle 1. One patient (Cohort 7) who received 6 mg as the first dose of CC-93269 and 10 mg on Day 8 of Cycle 1 developed CRS and died during the study. In this patient, grade 3 CRS was observed after the first dose of 6 mg on Day 1 of Cycle 1, and grade 5 CRS was observed after the second dose of 10 mg on Day 8 of Cycle 1 (Figure 4). This patient had extensive extramedullary disease at enrollment and a concurrent documented infection (Clostridium difficile), which was noted as suspected at the time of death.

[0360] Of the 27 CRS events, 8 (29.6%) were managed with dexamethasone and 10 (37.0%) with tocilizumab.

[0361] Example 2: Clinical Trial of CC-93269 in Relapsed / Refractory Multiple Myeloma (RRMM): Cohorts 8-9 In cohorts 8 and 9, a new dosing regimen was adopted to balance clinical activity and the overall safety profile, particularly minimizing the risk of severe cytokine release syndrome (CRS) in the first cycle.

[0362] CC-93269 was administered intravenously over 2 hours on days 1, 8, 15, and 22 for cycles 1 to 3, on days 1 and 15 for cycles 4 to 6, and on day 1 for cycles 7 and beyond, all in 28-day cycles. Patients began treatment with 3 mg on day 1 of cycle 1, and increased to 6 mg on days 8 and beyond.

[0363] Cohort 8 (n=6) and Cohort 9 (n=5) differed in baseline multiple myeloma tumor burden based on bone marrow plasma cell percentage and / or the presence of extramedullary disease (Cohort 8 included subjects with ≤50% bone marrow plasma cells (resected or aspirated) and ≤5 extramedullary disease, while Cohort 9 included subjects with ≥50% bone marrow plasma cells or >5 extramedullary disease). Based on the rationale that the only patient who experienced grade ≥3 CRS in Cohorts 1–7 had extensive extramedullary disease at enrollment, patients with low (Cohort 8) and high (Cohort 9) tumor burdens were enrolled to allow for evaluation of differences in tolerability.

[0364] safety In Cohorts 8 and 9, all patients received dexamethasone (up to 20 mg intravenously or equivalent) as prophylaxis against CRS before the first dose, before the second dose, at dose escalation, and after any dose interruption of 2 weeks or more that occurred during cycles 1 to 6. Patients were monitored, graded, and treated for CRS in the same manner as Cohorts 1 to 7 in Example 1.

[0365] Of the 11 patients receiving the 3 / 6 mg dose regimen, only 6 (54.5%) experienced no CRS, compared with 12 of the 12 subjects receiving the 6 mg, 6 / 10 mg, or 10 mg doses (100%) (Cohorts 5-7 in Example 1). In addition to a reduction in the frequency of CRS events, the severity of CRS in Cohorts 8 and 9 was generally reduced compared with Cohorts 5 to 7. All CRS events reported in Cohorts 8 and 9 were grade 1 (6 of 8 [75%]) or grade 2 (2 of 8 [25%]), with no grade 3 or higher CRS events reported. Grade 2 or higher events were reported in only 2 of 11 patients (18.2%) receiving the 3 / 6 mg dose regimen compared with 6 of 12 patients (50%) receiving the 6 mg, 6 / 10 mg, or 10 mg dose regimen (Figure 4). All CRS events in cohorts 8 and 9 resolved with standard treatment, including tocilizumab and / or dexamethasone.

[0366] No increase in the frequency or severity of CRS was observed in subjects with a high multiple myeloma tumor burden, i.e., percentage of bone marrow plasma cells or number of extramedullary lesions (cohort 9), compared with subjects with a low tumor burden (cohort 8).

[0367] In all cohorts 1 to 9 in Examples 1 and 2, the median time to the first occurrence of CRS was 1 day, with a maximum of 3 days. The majority of CRS events occurred with the first dose of C1D1 (73.3%), fewer with the second dose of C1D8 (23.3%), and few occurred with subsequent doses (2.7%, limited to events of grade 2 or less), suggesting that continued administration reduces the risk of CRS (Figure 5).

[0368] In all cohorts 1 to 9 in Examples 1 and 2, the median duration of CRS events was 2 days (range 1 to 7 days; only 4 of 36 cases lasted 3 days or longer).

[0369] Effectiveness Response was assessed in the same manner as for Cohorts 1-7 in Example 1. Subjects in Cohorts 8 and 9 (who received a maintenance dose of 6 mg or more after a starting dose of 3 mg) showed improved response compared to subjects in Cohorts 1-4 in Example 1 (who received a maintenance dose of 3 mg or less).

[0370] The overall response rate for patients treated at up to 6 mg (3 / 6 mg and 6 mg) was lower than that for patients treated at up to 10 mg (6 / 10 mg and 10 mg). Among patients treated at up to 6 mg (Cohorts 5, 8, and 9), a total of five responses were reported, for a preliminary overall response rate of 35.7%. Among nine patients treated at a maintenance dose of 10 mg (Cohorts 6 and 7), a total of eight responses were reported, for a preliminary overall response rate of 88.9% (Table 17).

[0371] These data suggest that a starting dosing schedule of 3 / 6 mg may reduce CRS, but a higher maintenance dose of 10 mg may improve efficacy, supporting the 3 / 6 / 10 mg regimen.

[0372] [Table 27]

[0373] Example 3: Effect of dexamethasone on CC-93269-mediated cytokine release, T cell activation, T cell proliferation, and redirected lysis of MM cell lines Four BCMA-expressing tumor cell lines (multiple myeloma cell lines: BCMA-high H929 (Cat. No. CRL-9068), BCMA-mid SKMM2 and -MM.1S (Cat. No. ACC-430), and BCMA-low KMS12-PE (Cat. No. ACC-606)) purchased from ATCC (Manassa, VA) were cocultured with T cells from three independent healthy donors (Bloodworks Northwest, Seattle, WA) at a 1:1 E:T ratio (i.e., 1 T cell:1 MM cell). Cocultures were treated with clinically relevant doses of dexamethasone (DEX: 0.0014 μM - 1 μM) or control dimethyl sulfoxide (DMSO), and various concentrations of CC-93269 (6.4-500 ng / mL; 0.033-2.6 nM) for 72 hours.

[0374] Dexamethasone was confirmed to reduce CC-93269-mediated release of IL-2 (48.3-74.1%), GM-CSF (47.5-67.8%), and TNF-α (46.3-61.8%), as measured using the Milliplex Human Cytokine / Chemokine Magnetic Bead Multiplex Assay (Millipore Sigma, Temecula, MA) according to the manufacturer's recommendations. Percent reductions were determined by co-treatment with 1 μM DEX compared to the DMSO control at the highest CC-93269 concentration tested. Cytokine levels were calculated using ForeCyt software (Intellicyt) according to a standard curve ranging from 2.29 to 7500 pg / mL. The effect of dexamethasone on CC-93269-induced cytokine secretion was determined by calculating the percent inhibition of 1 μM dexamethasone compared to the DMSO control and the highest concentration of CC-93269 tested according to the following formula: percent inhibition = 100 × ([cytokine concentration, DMSO control] − [cytokine secretion, 1 μM dexamethasone]) / [cytokine concentration, DMSO control].

[0375] FIG. 6 shows cytokine secretion from co-cultures with donor T cells from one healthy donor; results from all three independent healthy donors are summarized in Table 18.

[0376] [Table 28]

[0377] Dexamethasone had minimal effects on CC-93269-induced CD4 and CD8 T cell activation, proliferation, and redirected lysis of BCMA+ tumor cell lines (e.g., multiple myeloma cell lines).

[0378] Figure 7 shows the redirected lysis of BCMA+ tumor cell lines induced by CC-93269 after co-culture with donor T cells from one healthy donor; results from all three independent healthy donors are summarized in Table 19. 1 x 10 cells were cultured in a 96-well round-bottom plate and in a final volume of 100 μL. 4 1 x 10 CellTrace Violet-labeled T cells 4CellTrace CFSE-labeled target cells were seeded in the presence of different concentrations of CC-93269 combined with different concentrations of dexamethasone (7-point dose response). Co-cultures were incubated at 37°C and 5% CO2. After 72 hours of incubation, culture supernatants were collected and stored at -80°C. Following the manufacturer's instructions, cells were labeled with Live / Dead Fixable Aqua Dead Cell Stain for 30 minutes at room temperature. Cells were then stained with antibodies against the following cell surface markers: CD2, CD3, CD4, CD8, CD69, CD25, HLA-DR, and CD154 in a final volume of 50 μL of flow staining buffer. After staining for cell surface molecules, cells were washed once with 150 μL of flow staining buffer, resuspended in 50 μL of BD Cytofix fixation buffer, and incubated at room temperature for 30 minutes. Cells were washed with 150 μL of flow staining buffer, resuspended in a final volume of 50 μL of flow staining buffer, and analyzed using an IQUE Screener Plus instrument (Intellicyt, Albuquerque, NM). 100% viability was determined by the absolute number of viable tumor cells in the absence of CC-93269 or dexamethasone; an absolute number of viable cells of 0 was defined as 100% tumor cell death. The IC50 indicates the concentration of CC-93269 that inhibits the response midway between baseline and maximum after a specific exposure time. IC50 values ​​were calculated using nonlinear regression analysis, sigmoidal dose-response, using GraphPad Prism (version 5.0) software.

[0379] [Table 29]

[0380] Figure 8 shows CC-93269-induced T cell activation and proliferation after co-culture with donor T cells from one healthy donor. CD4 T cells proliferate in response to increasing doses of CC-93269. + and CD8 +CD4 T cells showed a dilution of CellTrace Violet after co-culture of healthy donor T cells with tumor cell lines compared to culture of T cells alone + and CD8 + The percentage of T cells is graphed as the mean ± standard deviation (SD) of triplicate samples. CD4 T cells expressing activation markers CD69, CD25, HLA-DR, and CD154 in response to increasing doses of CC-93269. + and CD8 + The percentage of T cells expressing activation markers after co-culture of healthy donor T cells with tumor cell lines compared to culture of T cells alone was significantly higher than that of CD4 T cells. + and CD8 + The percentage of T cells was graphed as the mean ± SD of triplicate samples. Both proliferation data and expression of activation markers were analyzed using ForCyt software (Intellicyt).

[0381] Concomitant treatment with dexamethasone had little inhibitory effect on CC-93269-mediated cytotoxicity, but strongly suppressed cytokine secretion, suggesting that it may be beneficial in the clinical management of cytokine release syndrome. For example, the present disclosure provides: [Section 1] 1. A multispecific antibody that binds BCMA and CD3 for use in treating a disorder associated with BCMA expression in a patient, wherein the treatment comprises: (i) an initiation phase, in which one or more initial doses of a multispecific antibody are administered to the patient; and (ii) a maintenance phase in which an initial maintenance dose of the multispecific antibody is administered to the patient, followed, if necessary, by at least one additional maintenance dose of the multispecific antibody. wherein each maintenance dose is greater than one or more starting doses; a multispecific antibody comprising administering the multispecific antibody in a dosing regimen; [Section 2] 2. The multispecific antibody of claim 1, wherein the multispecific antibody is a bispecific antibody, optionally wherein the bispecific antibody is a trivalent bispecific antibody comprising two Fab fragments of anti-BCMA antibodies, one Fab fragment of anti-CD3 antibodies, and one Fc portion, and is in the format BCMA Fab-Fc-CD3 Fab-BCMA Fab. [Section 3] the anti-BCMA antibody or antigen-binding fragment thereof, a) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 12; b) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 13; c) a VH region of SEQ ID NO: 10 and a VL region of SEQ ID NO: 14; d) a VH region of SEQ ID NO: 38 and a VL region of SEQ ID NO: 12; e) a VH region of SEQ ID NO: 39 and a VL region of SEQ ID NO: 12; f) a VH region of SEQ ID NO: 40 and a VL region of SEQ ID NO: 12, or g) the VH region of SEQ ID NO: 9 and the VL region of SEQ ID NO: 11 3. The multispecific antibody of claim 1, comprising a VH and a VL selected from the group consisting of: [Section 4] 4. The multispecific antibody of claim 1 , wherein the anti-CD3 antibody or antigen-binding fragment thereof comprises the VH region of SEQ ID NO: 7 and the VL region of SEQ ID NO: 8. [Section 5] 3. The multispecific antibody of claim 2, wherein the bispecific antibody comprises heavy and light chain polypeptides of SEQ ID NO: 48, SEQ ID NO: 55, SEQ ID NO: 56 and SEQ ID NO: 57 (x2). [Section 6] 6. The multispecific antibody according to claim 1 , wherein the initiation phase comprises a single fixed dose, optionally wherein the single fixed dose is between about 1.5 mg and 4.5 mg, for example about 3 mg. [Section 7] The multispecific antibody according to any one of claims 1 to 6, wherein the initial maintenance dose is a fixed dose of about 4.5 mg to 7.5 mg, for example about 6 mg. [Section 8] 6. The multispecific antibody according to claim 1 , wherein the initiation phase comprises a single fixed dose, optionally wherein the single fixed dose is between about 4.5 mg and 7.5 mg, for example about 6 mg. [Section 9] 9. The multispecific antibody according to any one of claims 1 to 6 and 8, wherein the initial maintenance dose is a fixed dose of about 8.5 mg to 11.5 mg, such as about 10 mg. [Section 10] 10. The multispecific antibody of any one of claims 1 to 9, wherein at least one additional maintenance dose is the same as the initial maintenance dose. [Section 11] 10. The multispecific antibody of any one of claims 1 to 9, wherein at least one additional maintenance dose is higher than the initial maintenance dose. [Section 12] 8. The multispecific antibody according to any one of claims 1 to 7, wherein at least one additional maintenance dose is a fixed dose of about 8.5 mg to 11.5 mg, such as about 10 mg. [Section 13] The patient has experienced or is at risk of experiencing an adverse event associated with administration of a multispecific antibody, wherein the treatment further comprises: a) steroids, such as corticosteroids; b) an antagonist of a cytokine receptor or cytokine selected from GM-CSF, IL-10, IL-10R, IL-6, IL-6 receptor (IL-6R), IFNγ, IFNGR, IL-2, IL-2R / CD25, MCP-1, CCR2, CCR4, MIPIβ, CCR5, TNFα, TNFR1, IL-1 and IL-1Rα / IL-1β, wherein the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid; c) molecules that decrease regulatory T cell (Treg) populations, such as cyclophosphamide; d) antipyretics, analgesics and / or antibiotics; and / or e) seizure prevention drugs, such as levetiracetam; 13. The multispecific antibody of any one of claims 1 to 12, comprising administering [Section 14] 12. The multispecific antibody of any one of claims 1 to 11, wherein the disorder associated with BCMA expression is a BCMA-expressing B-cell cancer, such as multiple myeloma. [Section 15] 13. The multispecific antibody of any one of claims 1 to 12, wherein the multispecific antibody is administered intravenously.

Claims

1. 1. A pharmaceutical composition comprising a bispecific antibody that binds BCMA and CD3 for use in treating a disorder associated with BCMA expression in a patient, comprising: wherein the treatment is (i) an initiation phase in which one or more starting doses of the bispecific antibody are administered to the patient, the one or more starting doses being a dose of about 1.5 mg to 4.5 mg; and (ii) a maintenance phase in which an initial maintenance dose of the bispecific antibody is administered to the patient, followed, if necessary, by at least one additional maintenance dose of the bispecific antibody; and administering the bispecific antibody in a dosing regimen comprising: wherein each maintenance dose is greater than one or more starting doses; The bispecific antibody is administered intravenously or subcutaneously; wherein the bispecific antibody: (a) an anti-BCMA antibody or antigen-binding fragment thereof comprising the VH region of SEQ ID NO: 10 and the VL region of SEQ ID NO: 14; and (b) an anti-CD3 antibody or antigen-binding fragment thereof, comprising the VH region of SEQ ID NO: 7 and the VL region of SEQ ID NO: 8; Including, the bispecific antibody is a trivalent bispecific antibody comprising two Fab fragments of the anti-BCMA antibody, one Fab fragment of the anti-CD3 antibody, and one Fc portion, and is in the format of BCMA Fab-Fc-CD3 Fab-BCMA Fab; and The bispecific antibody comprises heavy and light chain polypeptides of SEQ ID NO: 48, SEQ ID NO: 55, SEQ ID NO: 56 and two copies of SEQ ID NO:

57. Pharmaceutical compositions.

2. 10. The pharmaceutical composition of claim 1, wherein the initiation phase comprises a single fixed dose of about 3 mg.

3. 3. The pharmaceutical composition of claim 1 or 2, wherein the maintenance phase comprises two or more maintenance doses of about 4.5 mg to 25 mg.

4. 4. The pharmaceutical composition according to any one of claims 1 to 3, wherein the initial maintenance dose is a fixed dose of about 4.5 mg to 7.5 mg, for example about 6 mg, or the initial maintenance dose is a fixed dose of about 8.5 mg to 11.5 mg, for example about 10 mg.

5. 5. The pharmaceutical composition of any one of claims 1 to 4, wherein the starting dose of the bispecific antibody is a single fixed dose of about 3 mg and the first maintenance dose of the bispecific antibody is a fixed dose of about 6 mg.

6. 6. The pharmaceutical composition of claim 1, wherein at least one additional maintenance dose is the same as the initial maintenance dose.

7. 6. The pharmaceutical composition of claim 1, wherein at least one additional maintenance dose is greater than the initial maintenance dose.

8. 8. The pharmaceutical composition of any one of claims 1 to 7, wherein the at least one further maintenance dose is a fixed dose of about 8.5 mg to 11.5 mg, such as about 10 mg, optionally wherein the starting dose of the bispecific antibody is a single fixed dose of about 3 mg, the initial maintenance dose is a fixed dose of about 6 mg, and the at least one further maintenance dose is a fixed dose of about 10 mg.

9. 9. The pharmaceutical composition of any one of claims 1 to 5 or 7 to 8, wherein at least one additional maintenance dose comprises a second maintenance dose of the bispecific antibody, the second maintenance dose being greater than the first maintenance dose.

10. 10. The pharmaceutical composition of claim 9, wherein the first maintenance dose is a fixed dose of about 6 mg and the second maintenance dose is at the maximum dose level, optionally with the starting dose of the bispecific antibody being a single fixed dose of about 3 mg.

11. 11. The pharmaceutical composition of any one of claims 1 to 10, wherein a first maintenance dose of the bispecific antibody is administered to the patient three days after the starting dose, a second maintenance dose of the bispecific antibody is administered to the patient four days after the first maintenance dose, and optionally the third and subsequent maintenance doses are administered at about once per week or longer dosing intervals, for example the third and subsequent maintenance doses are administered at once per week dosing intervals (e.g. every 7 days), then once per two weeks dosing intervals (e.g. every 14 days), then once per four weeks dosing intervals (e.g. every 28 days).

12. The patient has experienced or is at risk of experiencing an adverse event associated with administration of the bispecific antibody, wherein the treatment further comprises: a) steroids, such as corticosteroids, optionally dexamethasone; b) an antagonist of a cytokine receptor or cytokine selected from GM-CSF, IL-10, IL-10R, IL-6, IL-6 receptor (IL-6R), IFNγ, IFNGR, IL-2, IL-2R / CD25, MCP-1, CCR2, CCR4, MIPIβ, CCR5, TNFα, TNFR1, IL-1 and IL-1Rα / IL-1β, wherein the antagonist is selected from an antibody or antigen-binding fragment, a small molecule, a protein or peptide, and a nucleic acid; c) molecules that reduce regulatory T cell (Treg) populations, such as cyclophosphamide; d) antipyretics, analgesics and / or antibiotics; and / or e) anti-seizure medications, such as levetiracetam; 12. The pharmaceutical composition of claim 1, comprising administering

13. 13. The pharmaceutical composition of any one of claims 1 to 12, wherein the disorder associated with BCMA expression is a BCMA-expressing B-cell cancer, such as multiple myeloma.

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