Anti-CD38 binding molecules and uses thereof

Abstract

The present disclosure provides antibodies, or antigen-binding fragments or derivatives thereof, that specifically bind to CD38. Also provided are polynucleotides encoding the antibodies, or antigen-binding fragments or derivatives thereof, as well as vectors and host cells comprising the polynucleotides. The present disclosure further provides methods of producing and / or using the antibodies, or antigen-binding fragments or derivatives thereof, that specifically bind to CD38. TIFF2025506341000029.tif97138

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 306,434, filed February 3, 2022; No. 63 / 370,025, filed August 1, 2022; and No. 63 / 383,736, filed November 15, 2022, each of which is incorporated by reference in its entirety into this specification.

[0002] Sequence Listing This application contains a Sequence Listing that has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. The ASCII copy was created on February 3, 2023, has the name 039WO1-Sequence-Listing, and is 173,284 bytes in size. [Background technology]

[0003] background CD38 is expressed in various cancers, such as various hematological malignancies including chronic lymphocytic leukemia (CLL), multiple myeloma (MM), Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma (PTCL), as well as various solid tumors including prostate cancer, non-small cell lung cancer (NSCLC), squamous cell carcinoma of the head and neck (SCCHN), ovarian cancer and liver cancer, and is therefore considered a potential target for directed therapy (Martin et al., Cells, 2019, 8:1522 (Non-Patent Document 1)).

[0004] Two anti-CD38 IgG antibodies, daratumumab and isatuximab, have been approved for the treatment of multiple myeloma (MM), the second most common blood cancer and accounting for 10% of all blood cancers. Despite these and other therapeutic developments, MM remains incurable with a 5-year survival rate of only 40%. Most MM patients become resistant to treatment (Marzo et al., Oncotarget, 2016, 7(37):60698-60711).

[0005] Antibodies and antibody-like molecules capable of multimerization, such as IgA and IgM antibodies, have emerged as promising drug candidates, allowing for improved specificity, improved avidity, and binding capacity to multiple binding targets, for example in the fields of immuno-oncology and infectious diseases. For example, U.S. Patent Nos. 9,951,134 (Patent Document 1), 9,938,347 (Patent Document 2), 10,570,191 (Patent Document 3), 10,604,559 (Patent Document 4), 10,618,978 (Patent Document 5), 10,787,520 (Patent Document 6), and 10,899,835 (Patent Document 7), and See U.S. Patent Application Publication Nos. 2019-0185570 (Patent Document 8), 2019-0330360 (Patent Document 9), 2019-0330374 (Patent Document 10), 2019-0338041 (Patent Document 11), and 2022-0106399 (Patent Document 12), the contents of which are incorporated by reference in their entirety into this specification.

[0006] There is a continuing need to improve the treatment of CD38-expressing cancers, including MM. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 9,951,134 [Patent Document 2] Same No. 9,938,347 [Patent Document 3] Same No. 10,570,191 [Patent Document 4] Same No. 10,604,559 [Patent Document 5] Same No. 10,618,978 [Patent Document 6] Same No. 10,787,520 [Patent Document 7] No. 10,899,835 [Patent Document 8] U.S. Patent Application Publication No. 2019-0185570 [Patent Document 9] Same No. 2019-0330360 [Patent Document 10] Same No. 2019-0330374 [Patent Document 11] Same No. 2019-0338041 [Patent Document 12] Same No. 2022-0106399 [Non-patent literature]

[0008] [Non-Patent Document 1] Martin et al.,Cells,2019,8:1522 [Non-Patent Document 2] Marzo et al.,Oncotarget,2016,7(37):60698-60711 Summary of the Invention

[0009] overview Provided herein is an antibody or antigen-binding fragment or derivative thereof comprising an antigen-binding domain that specifically binds CD38, the antigen-binding domain comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL comprise six immunoglobulin complementarity determining regions HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3, wherein HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are set forth in SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, respectively. and SEQ ID NO:71; SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:73, SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:81, SEQ ID NO:82, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:105, SEQ ID NO:10 6, SEQ ID NO:107, SEQ ID NO:109, SEQ ID NO:110 and SEQ ID NO:111; SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:117, SEQ ID NO:118 and SEQ ID NO:119; SEQ ID NO:121, SEQ ID NO:122, SEQ ID NO:123, SEQ ID NO:125, SEQ ID NO:126 and SEQ ID NO:127; SEQ ID NO:65, SEQ ID NO:134, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:182, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:135, SEQ ID NO: or the amino acid sequences of SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95.In some embodiments, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, respectively.

[0010] In some embodiments, the VH and VL are, respectively, SEQ ID NO:128 and SEQ ID NO:133; SEQ ID NO:56 and SEQ ID NO:60; SEQ ID NO:64 and SEQ ID NO:68; SEQ ID NO:72 and SEQ ID NO:76; SEQ ID NO:80 and SEQ ID NO:84; SEQ ID NO:88 and SEQ ID NO:92; SEQ ID NO:96 and SEQ ID NO:100; SEQ ID NO:104 and SEQ ID NO:108; SEQ ID NO:112 and SEQ ID NO:116; SEQ ID NO:120 and SEQ ID NO:124; SEQ ID NO:128 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:133; SEQ ID NO:130 and SEQ ID NO:68; SEQ ID NO:130 and SEQ ID NO:133; SEQ ID NO:131 and SEQ ID NO:68; SEQ ID NO:131 and SEQ ID NO:133; SEQ ID NO:132 and SEQ ID NO:68; SEQ ID NO:132 and SEQ ID NO:133; SEQ ID NO:64 and SEQ ID NO: SEQ ID NO:133; SEQ ID NO:136 and SEQ ID NO:86; SEQ ID NO:136 and SEQ ID NO:138; SEQ ID NO:136 and SEQ ID NO:139; SEQ ID NO:136 and SEQ ID NO:140; SEQ ID NO:136 and SEQ ID NO:141; SEQ ID NO:136 and SEQ ID NO:142; SEQ ID NO:137 and SEQ ID NO:86; SEQ ID NO:137 and SEQ ID NO:138; SEQ ID NO:137 and SEQ ID NO:139; SEQ ID NO:137 and SEQ ID NO:140; SEQ ID NO:137 and SEQ ID NO:141; SEQ ID NO:137 and SEQ ID NO:142; SEQ ID NO:88 and SEQ ID NO:138; SEQ ID NO:88 and SEQ ID NO:139; SEQ ID NO:88 and SEQ ID NO:140; SEQ ID NO:88 and SEQ ID NO:141; or SEQ ID NO:88 and SEQ ID NO:142. In some embodiments, VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO:128 and SEQ ID NO:133, respectively.

[0011] Further provided herein is an antibody, or antigen-binding fragment or derivative thereof, comprising an antigen-binding domain that specifically binds CD38, wherein the antigen-binding domain comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL are, respectively, SEQ ID NO:147 and SEQ ID NO:150; SEQ ID NO:147 and SEQ ID NO:151; SEQ ID NO:147 and SEQ ID NO:152; SEQ ID NO:147 and SEQ ID NO:153; SEQ ID NO:147 and SEQ ID NO:154; SEQ ID NO:147 and SEQ ID NO:155; SEQ ID NO:148 and SEQ ID NO:150; SEQ ID NO:148 and SEQ ID NO:151; SEQ ID NO:148 and SEQ ID NO:152; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:154; SEQ ID NO:1 or an antigen-binding fragment or derivative thereof comprising the amino acid sequences of SEQ ID NO:157 and SEQ ID NO:159; SEQ ID NO:157 and SEQ ID NO:160; SEQ ID NO:157 and SEQ ID NO:161; SEQ ID NO:158 and SEQ ID NO:159; SEQ ID NO:158 and SEQ ID NO:160; or SEQ ID NO:158 and SEQ ID NO:161.

[0012] In some embodiments, the antibody or antigen-binding fragment or derivative thereof is a multimeric antibody comprising 2, 4, 5, or 6 bivalent binding units and 4, 8, 10, or 12 antigen-binding domains, wherein at least 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 antigen-binding domains specifically bind to CD38, each binding unit comprising two heavy chains each comprising an IgA or IgM constant region or a multimerizing fragment or variant thereof, and wherein at least 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 heavy chain constant regions or fragments or variants thereof are associated with a copy of the VH.

[0013] In some embodiments, the antibody or antigen-binding fragment or derivative thereof is an Fv fragment, a single chain Fv fragment (scFv) or a disulfide-linked Fv fragment (sdFv). In some embodiments, the antibody or antigen-binding fragment or derivative thereof comprises a complete antibody, a Fab fragment, a Fab' fragment or a F(ab')2 fragment.

[0014] In some embodiments, the antibody or antigen-binding fragment or derivative thereof comprises a bivalent binding unit comprising two antigen-binding domains, at least one antigen-binding domain specifically binds to CD38, and each binding unit comprises two heavy chains, each comprising a heavy chain constant region, or a fragment or variant thereof, and at least one heavy chain constant region, or a fragment or variant thereof, associated with a copy of a VH.

[0015] In some embodiments, the heavy chain comprises an IgG heavy chain constant region, or a fragment or variant thereof, fused to the C-terminus of the VH. In some embodiments, the binding unit further comprises two light chains, each comprising a light chain constant region, or a fragment or variant thereof, fused to the C-terminus of the VL.

[0016] Further provided herein is a multimeric antibody comprising two, four, five or six bivalent binding units, each binding unit comprising two IgM or IgA heavy chain constant regions or multimerizable fragments or variants thereof, each associated with an antigen binding domain, wherein at least three, four, five, six, seven, eight, nine, ten, eleven or twelve of the antigen binding domains are CD38 antigen binding domains comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL are each associated with six immunoglobulin complementarity determining regions HCDR1, HCDR2, HCDR3, HCDR4, HCDR5, HCDR6, HCDR7, HCDR8, HCDR9, HCDR10, HCDR11, HCDR12, HCDR13, HCDR14, HCDR15, HCDR16, HCDR17, HCDR18, HCDR19, HCDR110, HCDR111, HCDR122, HCDR132, HCDR143, HCDR154, HCDR165, HCDR176, HCDR187, HCDR198, HCDR19 ... R3, LCDR1, LCDR2 and LCDR3, and HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:73, SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:81, SEQ ID NO:82, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:109, SEQ ID NO:110 and SEQ ID NO:111; SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:117, SEQ ID NO:118 and SEQ ID NO:119; SEQ ID NO:121, SEQ ID NO:122, SEQ ID NO:123, SEQ ID NO:125, SEQ ID NO:126 and SEQ ID NO:127; SEQ ID NO:65, SEQ ID NO:134, No. 67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:182, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:135, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:143, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:144, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:145, SEQ ID NO:94 and SEQ ID NO:95;or the multimeric antibody comprising the amino acid sequences of SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95. In some embodiments, the multimeric antibody is more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody. In some embodiments, the multimer can induce complement dependent cytotoxicity (CDC) of CD38 expressing cells with higher potency than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody;

[0017] In some embodiments, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, respectively. In some embodiments, the VH and VL are, respectively, SEQ ID NO:128 and SEQ ID NO:133; SEQ ID NO:56 and SEQ ID NO:60; SEQ ID NO:64 and SEQ ID NO:68; SEQ ID NO:72 and SEQ ID NO:76; SEQ ID NO:80 and SEQ ID NO:84; SEQ ID NO:88 and SEQ ID NO:92; SEQ ID NO:96 and SEQ ID NO:100; SEQ ID NO:104 and SEQ ID NO:108; SEQ ID NO:112 and SEQ ID NO:116; SEQ ID NO:120 and SEQ ID NO:124; SEQ ID NO:128 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:133; SEQ ID NO:130 and SEQ ID NO:68; SEQ ID NO:130 and SEQ ID NO:133; SEQ ID NO:131 and SEQ ID NO:68; SEQ ID NO:131 and SEQ ID NO:133; SEQ ID NO:132 and SEQ ID NO:68; SEQ ID NO:132 and SEQ ID NO:133; SEQ ID NO:64 and SEQ ID NO: SEQ ID NO:133; SEQ ID NO:136 and SEQ ID NO:86; SEQ ID NO:136 and SEQ ID NO:138; SEQ ID NO:136 and SEQ ID NO:139; SEQ ID NO:136 and SEQ ID NO:140; SEQ ID NO:136 and SEQ ID NO:141; SEQ ID NO:136 and SEQ ID NO:142; SEQ ID NO:137 and SEQ ID NO:86; SEQ ID NO:137 and SEQ ID NO:138; SEQ ID NO:137 and SEQ ID NO:139; SEQ ID NO:137 and SEQ ID NO:140; SEQ ID NO:137 and SEQ ID NO:141; SEQ ID NO:137 and SEQ ID NO:142; SEQ ID NO:88 and SEQ ID NO:138; SEQ ID NO:88 and SEQ ID NO:139; SEQ ID NO:88 and SEQ ID NO:140; SEQ ID NO:88 and SEQ ID NO:141; or SEQ ID NO:88 and SEQ ID NO:142. In some embodiments, VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO:128 and SEQ ID NO:133, respectively.

[0018] Further provided herein is a multimeric antibody comprising two, four, five or six bivalent binding units, each binding unit comprising two IgM or IgA heavy chain constant regions or multimerizing fragments or variants thereof, each associated with an antigen binding domain, wherein at least three, four, five, six, seven, eight, nine, ten, eleven or twelve of the antigen binding domains are CD38 antigen binding domains comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL are, respectively, SEQ ID NO:147 and SEQ ID NO:150; SEQ ID NO:147 and SEQ ID NO:151; SEQ ID NO:147 and SEQ ID NO:152; SEQ ID NO:147 and SEQ ID NO:153; SEQ ID NO:147 and SEQ ID NO:154; SEQ ID NO:147 and SEQ ID NO:155; SEQ ID NO:148 and SEQ ID NO:150; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:153; 151; SEQ ID NO:148 and SEQ ID NO:152; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:154; SEQ ID NO:148 and SEQ ID NO:155; SEQ ID NO:149 and SEQ ID NO:150; SEQ ID NO:149 and SEQ ID NO:151; SEQ ID NO:149 and SEQ ID NO:152; SEQ ID NO:149 and SEQ ID NO:153; SEQ ID NO:149 and SEQ ID NO:154; SEQ ID NO:149 and SEQ ID NO:155; SEQ ID NO:156 and SEQ ID NO:159; SEQ ID NO:156 and SEQ ID NO:160; SEQ ID NO:156 and SEQ ID NO:161; SEQ ID NO:157 and SEQ ID NO:159; SEQ ID NO:157 and SEQ ID NO:160; SEQ ID NO:157 and SEQ ID NO:161; SEQ ID NO:158 and SEQ ID NO:159; SEQ ID NO:158 and SEQ ID NO:160; or SEQ ID NO:158 and SEQ ID NO:161.

[0019] In some embodiments, multimeric antibodies are more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody, hi some embodiments, multimers can direct complement dependent cytotoxicity (CDC) of CD38 expressing cells with higher potency than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody.

[0020] In some embodiments, the multimeric antibody is a dimer or tetramer and comprises two or four bivalent IgA or IgA-like binding units and a J chain or a fragment or variant thereof, each binding unit comprising two IgA heavy chain constant regions or multimerizing fragments or variants thereof, each comprising a Cα3 domain and an α tailpiece (αtp) domain. In some embodiments, each of the IgA heavy chain constant regions or multimerizing fragments or variants thereof further comprises a Cα1 domain, a Cα2 domain, an IgA hinge region, or any combination thereof. In some embodiments, the IgA heavy chain constant region or multimerizing fragment or variant thereof is a human IgA constant region. In some embodiments, the J chain is a mature human J chain comprising the amino acid sequence of SEQ ID NO: 7 or a functional fragment or variant thereof.

[0021] In some embodiments, the multimeric antibody is a hexamer or pentamer and comprises five or six bivalent IgM or IgM-like binding units, each binding unit comprising two IgM heavy chain constant regions or multimerizing fragments or variants thereof, each comprising a Cμ4 and μ tailpiece (μtp) domain, in some embodiments, each of the IgM heavy chain constant regions or fragments or variants thereof further comprises a Cμ1 domain, a Cμ2 domain, a Cμ3 domain, or any combination thereof.

[0022] In some embodiments, the IgM heavy chain constant region or multimerizing fragment or variant thereof is a human IgM constant region. In some embodiments, each IgM heavy chain constant region comprises the amino acid sequence SEQ ID NO:1, SEQ ID NO:2, or a multimerizing variant or fragment thereof.

[0023] In some embodiments, each IgM heavy chain constant region is a variant human IgM constant region comprising one or more single amino acid substitutions, deletions or insertions compared to SEQ ID NO:1 or SEQ ID NO:2, and the multimeric antibody has reduced CDC activity compared to a multimeric antibody comprising in each IgM heavy chain constant region the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:2. In some embodiments, each variant human IgM constant region comprises an amino acid substitution corresponding to position L310 of SEQ ID NO:1 or SEQ ID NO:2, an amino acid substitution corresponding to position P311 of SEQ ID NO:1 or SEQ ID NO:2, an amino acid substitution corresponding to position P313 of SEQ ID NO:1 or SEQ ID NO:2, an amino acid substitution corresponding to position K315 of SEQ ID NO:1 or SEQ ID NO:2, or any combination thereof.

[0024] In some embodiments, each IgM heavy chain constant region is a variant human IgM constant region comprising one or more single amino acid substitutions, deletions or insertions compared to SEQ ID NO:1 or SEQ ID NO:2, such that upon administration to a subject animal, the multimeric antibody exhibits an increased serum half-life compared to a multimeric antibody comprising in each IgM heavy chain constant region the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:2 administered in the same manner to the same animal species. In some embodiments, the variant IgM heavy chain constant region comprises a half-life altering amino acid substitution at one or more amino acid positions corresponding to amino acids E345, S401, E402 or E403 of SEQ ID NO:1 or SEQ ID NO:2.

[0025] In some embodiments, the multimeric antibody is a pentamer and further comprises a J chain, or a functional fragment or functional variant thereof.

[0026] In some embodiments, the J chain is a mature human J chain comprising the amino acid sequence of SEQ ID NO: 7, or a functional fragment or variant thereof.

[0027] In some embodiments, the J chain is a variant J chain or a functional fragment thereof comprising one or more single amino acid substitutions, deletions or insertions compared to a reference J chain that is identical to the variant J chain except for the one or more single amino acid substitutions, deletions or insertions, and the variant J chain is capable of affecting the serum half-life of the multimeric antibody, such that upon administration to a subject animal, the multimeric antibody exhibits an increased serum half-life compared to a reference multimeric antibody that is identical except for the one or more single amino acid substitutions, deletions or insertions in the variant J chain and that is administered in the same manner to the same animal species. In some embodiments, the variant J chain comprises an amino acid substitution at an amino acid position corresponding to amino acid Y102 of the wild-type mature human J chain of SEQ ID NO:7. In some embodiments, the amino acid corresponding to Y102 of SEQ ID NO:7 is substituted with alanine (A). In some embodiments, the J chain comprises the amino acid sequence of SEQ ID NO:8.

[0028] In some embodiments, the J chain or functional fragment thereof is a modified J chain further comprising a heterologous moiety, which is fused or conjugated to the J chain or functional fragment or variant thereof. In some embodiments, the heterologous moiety is a polypeptide fused to the J chain or functional fragment or variant thereof. In some embodiments, the heterologous polypeptide is fused to the J chain or functional fragment or variant thereof via a peptide linker comprising at least 5 amino acids but not more than 25 amino acids. In some embodiments, the heterologous polypeptide is fused to the N-terminus of the J chain or functional fragment or variant thereof, the C-terminus of the J chain or functional fragment or variant thereof, or both the N-terminus and C-terminus of the J chain or functional fragment or variant thereof, and the heterologous polypeptides fused to both the N-terminus and C-terminus can be the same or different.

[0029] In some embodiments, the heterologous polypeptide comprises an scFv fragment. In some embodiments, the heterologous scFv fragment binds to CD3.

[0030] In some embodiments, the scFv fragment comprises an scFv heavy chain variable region (scFv VH) and an scFv light chain variable region (scFv VL), wherein the scFv VH comprises scFv VH complementarity determining regions VHCDR1, VHCDR2, and VHCDR3, and wherein the scFv VL comprises an scFv and VLCDR1, VLCDR2, VLCDR3, wherein VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3 comprise the amino acid sequences of SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:21, SEQ ID NO:22, and SEQ ID NO:23; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30, and SEQ ID NO:31; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30, and SEQ ID NO:33; SEQ ID NO:35, SEQ ID NO:36, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:41; SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:45; or SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:47, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:49. In some embodiments, VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2 and VLCDR3 comprise SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30 and SEQ ID NO:31, respectively. In some embodiments, scFv VH and scFv VL comprise an amino acid sequence that is at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO:16 and SEQ ID NO:20; SEQ ID NO:24 and SEQ ID NO:28; SEQ ID NO:24 and SEQ ID NO:32; SEQ ID NO:34 and SEQ ID NO:38; SEQ ID NO:42 and SEQ ID NO:44; or SEQ ID NO:46 and SEQ ID NO:48, respectively. In some embodiments, the scFv fragment comprises the scFv VH and scFv VL amino acid sequences of SEQ ID NO:24 and SEQ ID NO:28, respectively.

[0031] In some embodiments, the antibody or antigen-binding fragment or derivative thereof, or the multimeric antibody is capable of specifically binding to human CD38, non-human primate CD38, or human CD38 and non-human primate CD38. In some embodiments, the non-human primate CD38 is cynomolgus monkey CD38.

[0032] In some embodiments, the antibody or antigen-binding fragment or derivative thereof, or multimeric antibody specifically binds CD38 with an affinity characterized by a dissociation constant KD of less than or equal to 500 nM, 100 nM, 50.0 nM, 40.0 nM, 30.0 nM, 20.0 nM, 10.0 nM, 9.0 nM, 8.0 nM, 7.0 nM, 6.0 nM, 5.0 nM, 4.0 nM, 3.0 nM, 2.0 nM, 1.0 nM, 0.50 nM, 0.10 nM, 0.050 nM, 0.01 nM, 0.005 nM, or 0.001 nM, wherein CD38 is human CD38, cynomolgus CD38, or human CD38 and cynomolgus CD38.

[0033] In some embodiments, the antibody or antigen-binding fragment or derivative thereof, or the multimeric antibody is multispecific. In some embodiments, the antibody or antigen-binding fragment or derivative thereof, or the multimeric antibody is bispecific.

[0034] Further provided herein are compositions comprising the antibodies or antigen-binding fragments or derivatives thereof, or multimeric antibodies.

[0035] Further provided herein is a polynucleotide comprising a nucleic acid sequence encoding an antibody, or antigen-binding fragment or derivative thereof, or a multimeric antibody. Further provided herein is a vector comprising the polynucleotide. Further provided herein is a host cell comprising the vector. Further provided herein is a method for producing an antibody, or antigen-binding fragment or derivative thereof, or a multimeric antibody, comprising culturing a host cell and recovering the antibody, or antigen-binding fragment or derivative thereof.

[0036] Further provided herein are methods of treating cancer, comprising administering to a subject in need thereof an effective amount of an antibody or antigen-binding fragment or derivative thereof, or a multimeric antibody. In some embodiments, the subject is a human.

[0037] In some embodiments, the antibody or antigen-binding fragment or derivative thereof, multimeric antibody, or composition is for use in treating cancer in a subject in need thereof, hi some embodiments, the subject is a human.

[0038] Further provided herein is the use of an antibody, or an antigen-binding fragment or derivative thereof, or a multimeric antibody, in treating cancer in a subject in need thereof. Further provided herein is the use of an antibody, or an antigen-binding fragment or derivative thereof, or a multimeric antibody, in the manufacture of a medicament for treating cancer in a subject in need thereof. In some embodiments, the subject is a human. [Brief description of the drawings]

[0039] [Figure 1] 1A-1B show binding of chimeric CD38×CD3 IgM antibodies to human CD38 (FIG. 1A) and cynomolgus monkey ("cyno") CD38 (FIG. 1B). Data are expressed as relative light units (RLU) for binding of chimeric CD38×CD3 IgM antibodies (IgM A-1, IgM B-1, IgM C-1, IgM E-1, IgM F-1, and IgM H-1). [Diagram 2] Binding of chimeric CD38xCD3 IgM antibodies to NCI-H929 cells as measured by flow cytometry. Data are expressed as median fluorescence intensity for binding of chimeric CD38xCD3 IgM antibodies (IgM A-1, IgM B-1, IgM C-1, IgM E-1, IgM F-1, and IgM H-1). [Diagram 3]Figure 1 shows the binding of humanized CD38xCD3 IgM antibodies to human CD38 at different antibody concentrations as measured by ELISA. Data are expressed in relative light units (RLU) for humanized CD38xCD3 IgM antibodies (IgM B-2, IgM B-4, IgM E-2, IgM E-4, IgM OKT10-2, and IgM OKT10-4). [Figure 4] FIG. 1 shows the pharmacokinetics of anti-CD38×CD3 IgM antibodies (IgM B-2, IgM E-2, and IgM OKT10-2) in a mouse model. [Diagram 5] A shows dose response curves (% kill) for killing of H929 cells with increasing concentrations of CD38xCD3 IgG and IgM B-2. B shows the resulting TNF-α levels after treatment with increasing concentrations of CD38xCD3 IgG and IgM B-2. C shows the resulting IFN-γ levels after treatment with increasing concentrations of CD38xCD3 IgG and IgM B-2. [Figure 6] A shows the CD8+ T cell counts for each PBMC donor after treatment with CD38×CD3 IgG, or IgM B-2. B shows the ratio of CD8+ T cell counts to regulatory T cell counts (Treg) for each PBMC donor after treatment with CD38×CD3 IgG, or IgM B-2. C shows the CD38hi regulatory T cell counts for each PBMC donor after treatment with CD38×CD3 IgG, or IgM B-2. [Figure 7]Figure 7A shows in vitro colony formation of multiple myeloma cells from four different donors after treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2. Figure 7B shows in vitro colony formation of erythroid cells from two different normal bone marrow donors after treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2. Total erythroid cells at the developmental stages of CFU-E (late erythroid progenitor) and BFU-E (early erythroid progenitor) were measured. Figure 7C shows in vitro colony formation of granulocyte-macrophage progenitor cells (CFU-GM) from two different normal bone marrow donors after treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2. [Figure 8] The levels of T cell-cell combat are shown when CD4+ and CD8+ T cells were treated with IgM B-2 or CD38xCD3 IgG. [Figure 9] Both A and B show the median BLI signal (tumor burden) over time in two independent studies in animals receiving vehicle, CD38xCD3 IgG, or IgM B-2. [Figure 10-1] Figures 10A-10F show the BLI signal (tumor burden) over time for each of the animals treated with vehicle (Figure 10A), 0.5 mg / kg CD38xCD3 IgG (Figure 10B), 0.1 mg / kg CD38xCD3 IgG (Figure 10C), 10 mg / kg IgM B-2 (Figure 10D), 3 mg / kg IgM B-2 (Figure 10E), and 1 mg / kg IgM B-2 (Figure 10F). [Figure 10-2] See description of Figure 10-1. [Figure 11] A-B show the numbers of CD4+ T cells (A) and CD8+ T cells (B) per microliter of blood in mice treated with vehicle, 0.5 or 0.1 mg / kg CD38xCD3 IgG, or 10, 3 or 1 mg / kg IgM B-2. [Figure 12]AB show the numbers of CD4+ T cells (A) and CD8+ T cells (B) per bone marrow sample from mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2. [Figure 13] AB show the numbers of CD4+ T cells (A) and CD8+ T cells (B) per mg of spleen samples from mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2. [Figure 14] Figure 14A shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in the peripheral blood of mice treated with vehicle, 0.1 or 0.5 mg / kg CD38xCD3 IgG, or 1, 3, or 10 mg / kg IgM B-2. Figure 14B shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in the bone marrow of mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2. Figure 14C shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in the spleen of mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2. [Figure 15-1] Figure 15 shows dose response curves for complement-mediated cytotoxicity (% kill) of various cell lines with increasing concentrations of IgM B-2, CD38 IgG#Y, CD38 IgG#Z, and isotype control IgM antibodies: Figure 15A: MOLP-8 cells, Figure 15B: LP-1 cells, Figure 15C: Ramos cells, Figure 15D: Raji cells, Figure 15E: RPMI-8226 cells, Figure 15F: NCI-H929 cells, Figure 15G: OPM-2 cells, Figure 15H: MOLM-13 cells. [Figure 15-2] See description of Figure 15-1. [Figure 15-3] See description of Figure 15-1. [Figure 16] A shows the viability of primary NK cells as a function of antibody concentration. B shows the viability of primary monocytes as a function of antibody concentration. [Figure 17]BLI signal in the disseminated NCI-H929-luc-gfp-Puro tumor model in NSG-MHC I / II DKO mice humanized with PBMC and treated with IgM B-2 (10 mg / kg) three times a week for 11 doses. Error bars represent the mean ± SEM of 9 animals per group. Statistical analysis represents a comparison with the vehicle control group. Each vertical line indicates the day of antibody dosing. [Figure 18A] Figure 1 shows tumor volume over time as a function of IGM B-2 dose in a humanized mouse NCI-H929 tumor xenograft model. Error bars represent the mean ± SEM of 9 animals per group. Statistical analysis represents a comparison with the vehicle control group. Treatment was performed three times weekly for a total of 15 doses. Each triangle on the top indicates the day of antibody dosing. [Figure 18B] The percent body weight change following IGM B-2 treatment is shown. [Figure 18C] Details of D21 results from panel A are shown. P values ​​obtained by comparing treated groups with the vehicle group: **p=0.0049 (30 mg / kg), **p=0.0045 (10 mg / kg), p=0.15 (3 mg / kg) and p=0.18 (1 mg / kg). [Figure 18D] 1 shows overall survival in a humanized mouse NCI-H929 tumor xenograft model. [Figure 19A] Tumor volume over time as a function of IGM B-2 dose in a humanized Raji mouse tumor xenograft model. Error bars represent the mean ± SEM of 9 animals per group. Statistical analysis represents a comparison with the vehicle control group. Treatment was performed three times weekly for a total of 15 doses. Each triangle on the top indicates the day of antibody dosing. [Figure 19B] Details of D25 results from panel A are shown. P values ​​obtained by comparing treated groups with vehicle group, ****p<0.0001 (30 mg / kg), ***p=0.0008 (10 mg / kg), p=0.12 (3 mg / kg) and p=0.33 (1 mg / kg). [Figure 19C] The percent body weight change following IGM B-2 treatment is shown. [Figure 19D]1 shows overall survival in a humanized Raji xenograft mouse tumor xenograft model. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] definition It should be noted that the term "a" or "an" entity refers to one or more of that entity; for example, "a binding molecule" is understood to represent one or more binding molecules. Thus, the terms "a" (or "an"), "one or more," and "at least one" may be used interchangeably herein.

[0041] Furthermore, "and / or" as used herein should be considered as specifically disclosing each of the two specified features or components with or without the other. Thus, the term "and / or" when used herein in phrases such as "A and / or B" is intended to include "A and B", "A or B", "A" (single), and "B" (single). Similarly, the term "and / or" when used in phrases such as "A, B, and / or C" is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A, or C; A, or B; B, or C; A, and C; A, and B; B, and C; A (single); B (single); and C (single).

[0042] Unless otherwise defined, scientific and technical terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. For example, the Concise Dictionary of Biomedicine and Molecular Biology, Juo, Pei-Show, 2nd ed., 2002, CRC Press; The Dictionary of Cell and Molecular Biology, 3rd ed., 1999, Academic Press; and the Oxford Dictionary of Biochemistry and Molecular Biology, Revised, 2000, Oxford University Press provide those skilled in the art with a general dictionary of many of the terms used in this disclosure.

[0043] Units, prefixes, and symbols are expressed in the form accepted by the Systeme International de Unites (SI). Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, amino acid sequences are written from left to right in amino to carboxy orientation. The headings provided herein are not limitations of the various embodiments of the disclosure, which may be incorporated by reference into the specification in its entirety. Thus, the terms defined immediately below are more fully defined by reference to the specification in its entirety.

[0044] As used herein, the term "polypeptide" is intended to encompass the singular "polypeptide" and the plural "polypeptides" and refers to a molecule composed of monomers (amino acids) linearly linked by amide bonds (also known as peptide bonds). The term "polypeptide" refers to any chain of two or more amino acids and does not refer to a specific length of the product. Thus, peptides, dipeptides, tripeptides, oligopeptides, "proteins," "amino acid chains," or other terms used to refer to chains of two or more amino acids are included within the definition of "polypeptide," and the term "polypeptide" may be used in place of or interchangeably with any of these terms. The term "polypeptide" is also intended to refer to products of post-expression modifications of the polypeptide, including, but not limited to, glycosylation, acetylation, phosphorylation, amidation, and derivatization with known protecting / blocking groups, proteolytic cleavage, or modification with non-naturally occurring amino acids. Polypeptides can be obtained from biological sources or produced by recombinant technology, but are not necessarily translated from a specified nucleic acid sequence. It may be produced in any manner, including by chemical synthesis.

[0045] The polypeptides disclosed herein can be about 3 or more, 5 or more, 10 or more, 20 or more, 25 or more, 50 or more, 75 or more, 100 or more, 200 or more, 500 or more, 1,000 or more, or 2,000 or more amino acids in size. A polypeptide can have a defined three-dimensional structure, but does not necessarily have such a structure. A polypeptide that has a defined three-dimensional structure is said to be folded, and a polypeptide that does not have a defined three-dimensional structure but can adopt a number of different conformations is said to be unfolded. As used herein, the term glycoprotein refers to a protein associated with at least one carbohydrate moiety that is attached to the protein through an oxygen- or nitrogen-containing side chain of an amino acid, such as serine or asparagine.

[0046] An "isolated" polypeptide or a fragment, variant or derivative thereof is intended to mean a polypeptide that is not in its natural surroundings. No particular level of purification is required. For example, an isolated polypeptide can be removed from its native or natural environment. Recombinantly produced, host cell expressed polypeptides and proteins are considered isolated as disclosed herein, as are natural or recombinant polypeptides that have been separated, fractionated, or partially or substantially purified by any suitable technique.

[0047] As used herein, the term "non-naturally occurring polypeptide" or any grammatical variation thereof is a qualified definition that expressly excludes, but only excludes, forms of a polypeptide that have been or may be declared or construed as "naturally occurring" by a judicial or administrative agency or judicial body.

[0048] Other polypeptides disclosed herein are fragments, derivatives, analogs or variants of the aforementioned polypeptides, and any combination thereof. The terms "fragment", "variant", "derivative" and "analog" as disclosed herein encompass any polypeptide that retains at least some of the properties of the corresponding native antibody or polypeptide, such as specific binding to an antigen. Fragments of polypeptides include, for example, proteolytic fragments and deletion fragments, as well as the specific antibody fragments discussed elsewhere herein. Variants of, for example, polypeptides include the above fragments, as well as polypeptides having altered amino acid sequences due to amino acid substitutions, deletions or insertions. In certain embodiments, variants may not be naturally occurring. Non-naturally occurring variants may be produced using mutagenesis techniques known in the art. Variant polypeptides may include conservative or non-conservative amino acid substitutions, deletions or additions. Derivatives are polypeptides that have been modified to exhibit additional features not found in the original polypeptide. Examples include fusion proteins. Variant polypeptides may also be referred to herein as "polypeptide analogs". As used herein, the "derivative" of a polypeptide may also refer to a subject polypeptide having one or more amino acids that are chemically derivatized by reaction of a functional side group. Peptides that contain one or more derivatives of the 20 standard amino acids are also included as "derivatives". For example, 4-hydroxyproline may be substituted for proline, 5-hydroxylysine may be substituted for lysine, 3-methylhistidine may be substituted for histidine, homoserine may be substituted for serine, and ornithine may be substituted for lysine.

[0049] A "conservative amino acid substitution" refers to a substitution in which one amino acid is replaced with another amino acid having a similar side chain. Families of amino acids with similar side chains have been defined in the art, including basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., asparagine, glutamine, serine, threonine, tyrosine, cysteine), non-polar side chains (e.g., glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). For example, substituting phenylalanine for tyrosine is a conservative substitution. In certain embodiments, conservative substitutions in the sequences of the polypeptides and antibodies of the present disclosure do not cause a polypeptide or antibody containing the amino acid sequence to lose its ability to bind to the antigen to which the polypeptide or antibody binds. Methods for identifying conservative nucleotide and amino acid substitutions that do not lose antigen binding are well known in the art (see, e.g., Brummell et al., Biochem. 32:1180-1 187 (1993); Kobayashi et al., Protein Eng. 12(10):879-884 (1999); and Burks et al., Proc. Natl. Acad. Sci. USA 94:.412-417 (1997)).

[0050] The term "polynucleotide" is intended to encompass single and multiple nucleic acids and refers to an isolated nucleic acid molecule or construct, such as messenger RNA (mRNA), cDNA, or plasmid DNA (pDNA). A polynucleotide may contain conventional phosphodiester bonds or non-conventional bonds (e.g., amide bonds, as in peptide nucleic acids (PNA)). The term "nucleic acid" or "nucleic acid sequence" refers to any one or more nucleic acid segments, e.g., DNA or RNA fragments, present in a polynucleotide.

[0051] An "isolated" nucleic acid or polynucleotide is intended to mean any form of nucleic acid or polynucleotide that is separated from its natural environment. For example, a gel-purified polynucleotide or a recombinant polynucleotide encoding a polypeptide contained in a vector would be considered "isolated". Also, a polynucleotide segment that has been engineered to have a restriction site for cloning, such as a PCR product, is considered "isolated". Further examples of isolated polynucleotides include recombinant polynucleotides maintained in heterologous host cells or polynucleotides that have been purified (partially or substantially) in a non-native solution (e.g., buffer or saline). Isolated RNA molecules include in vivo or in vitro RNA transcripts of a polynucleotide, where the transcript is not found in nature. Isolated polynucleotides or nucleic acids further include such molecules that are produced synthetically. In addition, the polynucleotide or nucleic acid may be or may include regulatory elements, such as a promoter, a ribosome binding site, or a transcription terminator.

[0052] As used herein, the term "non-naturally occurring polynucleotide" or any grammatical variation thereof is a qualified definition that expressly excludes, but only, forms of nucleic acid or polynucleotide that have been or may be declared or construed as "naturally occurring" by a judicial or administrative agency or judicial body.

[0053] As used herein, a "coding region" is a portion of a nucleic acid consisting of codons that are translated into amino acids. A "stop codon" (TAG, TGA, or TAA) can be considered part of a coding region even though it is not translated into amino acids, except that any adjacent sequences, such as promoters, ribosome binding sites, transcription terminators, introns, and the like, are not part of a coding region. Two or more coding regions can be present in a single polynucleotide construct, such as on a single vector, or on separate polynucleotide constructs, such as in separate (different) vectors. Furthermore, any vector may contain a single coding region or may include two or more coding regions, for example, a single vector may separately encode an immunoglobulin heavy chain variable region and an immunoglobulin light chain variable region. In addition, a vector, polynucleotide, or nucleic acid may include a heterologous coding region that may or may not be fused to another coding region. Heterologous coding regions include, but are not limited to, those that encode specialized elements or motifs, such as secretory signal peptides or heterologous functional domains.

[0054] In certain embodiments, the polynucleotide or nucleic acid is DNA. In the case of DNA, a polynucleotide comprising a nucleic acid encoding a polypeptide may usually include a promoter and / or other transcriptional or translational control elements operably associated with one or more coding regions. Operable association refers to when a coding region for a gene product (e.g., a polypeptide) is associated with one or more regulatory sequences in such a way that the gene product is expressed under the influence or control of the regulatory sequence(s). Two DNA fragments (e.g., a polypeptide coding region and its associated promoter) are "operably associated" if induction of promoter function results in transcription of an mRNA encoding a desired gene product, and if the nature of the linkage between the two DNA fragments does not interfere with the ability of the expression regulatory sequence to induce expression of the gene product or the ability of the DNA template to be transcribed. Thus, a promoter region will be operably associated with a nucleic acid encoding a polypeptide if the promoter has the ability to effect transcription of that nucleic acid. The promoter may be a cell-specific promoter that induces substantial transcription of the DNA in a given cell. Other transcription control elements, besides a promoter, for example enhancers, operators, repressors, and transcription termination signals, can be operably associated with the polynucleotide to direct cell-specific transcription.

[0055] A variety of transcription control regions are known to those skilled in the art. These include, but are not limited to, transcription control regions that function in vertebrate cells, such as promoters and enhancer segments from cytomegalovirus (immediate early promoter in conjunction with intron A), Simian Virus 40 (early promoter) and retroviruses (e.g., from Rous sarcoma virus). Other transcription control regions include those derived from vertebrate genes, such as actin, heat shock proteins, bovine growth hormone and rabbit β-globin, as well as other sequences capable of controlling gene expression in eukaryotic cells. Further suitable transcription control regions include tissue-specific promoters and enhancers, as well as lymphokine-inducible promoters (e.g., promoters that can be induced by interferons or interleukins).

[0056] Similarly, a variety of translation control elements are known to those skilled in the art, including, but not limited to, ribosome binding sites, translation initiation and termination codons, and elements derived from picornaviruses (particularly internal ribosome entry sites, also called CITE sequences, or IRES).

[0057] In other embodiments, the polynucleotide may be in the form of RNA, such as messenger RNA (mRNA), transfer RNA, or ribosomal RNA.

[0058] The polynucleotide and nucleic acid coding regions may be associated with additional coding regions encoding secretory or signal peptides that induce secretion of the polypeptides encoded by the polynucleotides disclosed herein. According to the signal hypothesis, proteins secreted by mammalian cells have a signal peptide or secretory leader sequence that is cleaved from the mature protein once the growing protein chain begins to be exported across the rough endoplasmic reticulum. Those skilled in the art recognize that polypeptides secreted by vertebrate cells may have a signal peptide fused to the N-terminus of the polypeptide, which signal peptide is cleaved from the complete or "full-length" polypeptide to generate the secretory or "mature" form of the polypeptide. In certain embodiments, a native signal peptide (e.g., an immunoglobulin heavy or light chain signal peptide), or a functional derivative of that sequence, that retains the ability to induce secretion of a polypeptide operably associated therewith, is used. Alternatively, a heterologous mammalian signal peptide or a functional derivative thereof may be used. For example, the wild-type leader sequence may be substituted with the leader sequence of human tissue plasminogen activator (TPA) or mouse β-glucuronidase.

[0059] As used herein, the term "binding molecule" in its broadest sense refers to a molecule that specifically binds to a binding target, such as an epitope or antigenic determinant. As further described herein, a binding molecule may include one or more of the "antigen-binding domains" described herein. Non-limiting examples of binding molecules are antibodies or antibody-like molecules that retain antigen-specific binding, or antibody-like molecules or fragments thereof as described in detail herein that retain antigen-specific binding. In certain embodiments, the "binding molecule" includes antibodies or antibody-like molecules as described in detail herein.

[0060] As used herein, the term "binding domain" or "antigen-binding domain" (which may be used interchangeably) refers to a region or fragment of a binding molecule (e.g., an antibody or antibody-like molecule) necessary and sufficient to specifically bind to a binding target (e.g., an epitope). For example, an "Fv" (e.g., the heavy and light chain variable regions of an antibody, either as two separate polypeptide subunits or as a single chain) is considered to be a "binding domain". Other antigen-binding domains include, but are not limited to, the heavy chain variable region (VHH) of an antibody from a camelid species, or six immunoglobulin complementarity determining regions (CDRs) expressed within a scaffold (e.g., a fibronectin scaffold). A "binding molecule" as described herein, e.g., an antibody or antibody-like molecule, may contain 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or in some cases more "antigen-binding domains". As used herein, a "binding unit associated antigen-binding domain" refers to an antigen-binding domain that is a portion of an antibody heavy chain and / or an antibody light chain. The term "J chain associated antigen-binding domain" refers to an antigen-binding domain associated with a modified J chain as described herein, e.g., an scFv fused to a wild-type human J chain or a functional fragment or variant thereof.

[0061] The terms "antibody" and "immunoglobulin" may be used interchangeably herein. An antibody provided in this disclosure must specifically bind to an antigen, i.e., it contains at least the variable domain of the heavy chain (in the case of camelid species), or at least the variable domains of the heavy and light chains. Basic immunoglobulin structure in vertebrate systems is relatively well understood. See, e.g., Harlow et al., Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988). Unless otherwise specified, the term "antibody" encompasses everything from small antigen-binding fragments of antibodies to full-sized antibodies (e.g., an IgG antibody comprising two IgG heavy chains or fragments thereof and two light chains, an IgA antibody comprising two, four or eight IgA heavy chains or multimerizing fragments thereof and two, four or eight light chains, optionally comprising a J chain or a functional fragment or variant thereof, and / or a secretory component, or an IgM antibody comprising ten or twelve IgM heavy chains or multimerizing fragments thereof and ten or twelve light chains, optionally comprising a J chain or a functional fragment or variant thereof).

[0062] The term "immunoglobulin" includes a wide variety of classes of polypeptides that can be distinguished biochemically. Those skilled in the art will recognize that heavy chains are classified as, for example, gamma, mu, alpha, delta, or epsilon (γ, μ, α, δ, ε), with several subclasses within them (e.g., γ1-γ4, or α1-α2). The nature of the chain determines the "isotype" of the antibody as IgG, IgM, IgA, IgD, or IgE, respectively. Immunoglobulin subclasses (subtypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA1, IgA2, etc., are well characterized and are known to confer functional specialization. Modified forms of each of these immunoglobulins would be readily discernible to one of skill in the art in light of the present disclosure, and are therefore within the scope of the present disclosure.

[0063] Light chains are classified as either kappa or lambda (κ, λ). Each heavy chain class can be associated with either kappa or lambda light chains. Usually, when immunoglobulins are expressed, for example, by hybridomas, B cells, or genetically engineered host cells, the light and heavy chains are covalently linked to each other via disulfide bonds, and the "tail" portions of the two heavy chains are linked to each other by covalent disulfide bonds or non-covalent bonds. In the heavy chains, the amino acid sequences run from the N-terminus at the forked ends of the Y configuration to the C-terminus at the end of each chain. The basic structure of a certain antibody, for example an IgG antibody, comprises two heavy chain subunits and two light chain subunits covalently linked via disulfide bonds to form a "Y" structure (also referred to herein as an "H2L2" structure or "binding unit").

[0064] The term "binding unit" is used herein to refer to a portion of a binding molecule (e.g., an antibody or antibody-like molecule) that corresponds to a standard "H2L2" immunoglobulin structure (e.g., two heavy chains or fragments thereof and two light chains or fragments thereof). In certain embodiments, a binding unit may correspond to two heavy chains, e.g., of a camelid antibody. In certain embodiments, for example, when the binding molecule is a bivalent IgG antibody or antibody-like molecule, the terms "binding molecule" and "binding unit" are equivalent. In other embodiments, for example, when the binding molecule is a multimer, e.g., a dimeric or tetrameric IgA antibody or IgA-like antibody, a pentameric IgM antibody or IgM-like antibody, or a hexameric IgM antibody or IgM-like antibody, the binding molecule comprises two or more "binding units", two or four in the case of an IgA dimer or tetramer, respectively, or five or six in the case of an IgM pentamer or hexamer, respectively. A binding unit need not contain a full-length antibody heavy / light chain, but will typically be bivalent, i.e., contain two "antigen-binding domains" as defined above. As used herein, certain binding molecules provided in the present disclosure are "dimers" or "tetramers" and contain two or four bivalent binding units comprising an IgA heavy chain constant region or a multimerizing fragment thereof. Certain binding molecules provided in the present disclosure are "pentamers" or "hexamers" and contain five or six bivalent binding units comprising an IgM heavy chain constant region or a multimerizing fragment thereof. A binding molecule, e.g., an antibody or antibody-like molecule, that contains more than one, e.g., two, four, five or six, binding units, is referred to herein as "multimeric."

[0065] The term "J chain", as used herein, refers to a J chain associated with a pentameric IgM or dimeric or tetrameric IgA antibody of any animal species, any functional fragment thereof, derivative thereof and / or variant thereof, including the mature human J chain whose amino acid sequence is presented as SEQ ID NO: 7. A variety of J chain variants and modified J chain derivatives are disclosed herein. As one of skill in the art will recognize, a "functional fragment" or "functional variant" encompasses fragments and variants that are capable of associating with an IgM heavy chain constant region to form a pentameric IgM antibody (or that are capable of associating with an IgA heavy chain constant region to form a dimeric or tetrameric IgA antibody).

[0066] The term "modified J chain" is used herein to refer to a derivative of a J chain polypeptide that includes a heterologous moiety (e.g., a heterologous polypeptide, e.g., an exogenous binding domain, introduced into the J chain polypeptide). Introduction can be accomplished by any means, including direct or indirect fusion of a heterologous polypeptide or other moiety, or conjugation via a peptide or chemical linker. The term "modified human J chain" includes, without limitation, a human J chain comprising the amino acid sequence of SEQ ID NO:7, or a functional fragment or functional variant thereof, that has been modified by the introduction of a heterologous moiety (e.g., a heterologous polypeptide, e.g., an exogenous binding domain). In certain embodiments, the heterologous moiety does not interfere with efficient polymerization of IgM into pentamers, or IgA into dimers or tetramers, and binding of such polymers to targets. Exemplary modified J chains can be found, for example, in U.S. Pat. Nos. 9,951,134, 10,975,147, 10,400,038, and 10,618,978, and U.S. Patent Application Publication No. US-2019-0185570, each of which is incorporated by reference in its entirety.

[0067] As used herein, the terms "IgM-derived binding molecule", "IgM-like antibody", "IgM-like binding unit" or "IgM-like heavy chain constant region" refer to a binding molecule, antibody, binding unit or heavy chain constant region derived from a variant antibody that still retains the structural portions of the IgM heavy chain necessary to confer the ability to bind antigen and to form multimers (i.e., hexamers) or to form pentamers in association with a J chain. An IgM-like antibody or IgM-derived binding molecule typically contains at least the Cμ4 and μ tailpiece (μtp) domains of the IgM constant region, as well as an antigen-binding domain or subunits thereof, but may also contain heavy chain constant region domains from other antibody isotypes (e.g., IgG) from the same or different species. Similarly, an IgM-like antibody or IgM-derived binding molecule may be an antibody fragment in which one or more constant regions have been deleted, so long as the IgM-like antibody is capable of binding antigen and forming hexamers and / or pentamers. Thus, an IgM-like antibody or an IgM-derived binding molecule may be, for example, a hybrid IgM / IgG antibody, or a "multimerizing fragment" of an IgM antibody.

[0068] As used herein, the terms "IgA-derived binding molecule", "IgA-like antibody", "IgA-like binding unit" or "IgA-like heavy chain constant region" refer to a binding molecule, antibody, binding unit or heavy chain constant region derived from a variant antibody that still retains the structural portion of the IgA heavy chain required for binding to antigen and conferring the ability to form multimers (i.e., dimers or tetramers) in association with a J chain. An IgA-like antibody or IgA-derived binding molecule typically contains at least the Cα3 and α tailpiece (αtp) domains of the IgA constant region, as well as an antigen-binding domain or subunit thereof, but may also contain heavy chain constant region domains from other antibody isotypes (e.g., IgG) from the same or different species. An IgA-like antibody or IgA-derived binding molecule may also be an antibody fragment in which one or more constant regions have been deleted, so long as the IgA-like antibody has the ability to bind to antigen and form dimers in association with a J chain. Thus, an IgA-like antibody or an IgA-derived binding molecule may be, for example, a hybrid IgA / IgG antibody, or a "multimerizing fragment" of an IgA antibody.

[0069] The terms "valency", "monovalent", "bivalent", "multivalent" and grammatical equivalents refer to the number of antigen-binding domains in a given binding molecule (e.g., an antibody or antibody-like molecule) or a given binding unit. Thus, for a given binding molecule, e.g., an IgM antibody, an IgM-like antibody or a multimerizing fragment thereof, the terms "bivalent", "tetravalent" and "hexavalent" refer to the presence of two antigen-binding domains, four antigen-binding domains and six antigen-binding domains, respectively. A typical IgM or IgM-like antibody or IgM-derived binding molecule, in which each binding unit is bivalent, may have a valency of 10 or 12. A bivalent or multivalent binding molecule (e.g., an antibody or antibody-like molecule) may be monospecific (i.e., all of the antigen-binding domains are the same) or bispecific or multispecific (e.g., where two or more antigen-binding domains are different, e.g., binding to different epitopes on the same antigen or to completely different antigens).

[0070] The term "epitope" includes any molecular determinant capable of specific binding to an antigen-binding domain of an antibody or antibody-like molecule. In certain embodiments, an epitope may comprise chemically active surface groups of a molecule, such as amino acids, sugar side chains, phosphoryl or sulfonyl, and in certain embodiments may have three-dimensional structural characteristics and / or specific charge characteristics. An epitope is the area of ​​a target that is bound by the antigen-binding domain of an antibody.

[0071] The term "target" is used in the broadest sense to include any substance that can be bound by a binding molecule, such as an antibody or antibody-like molecule. A target can be, for example, a polypeptide, a nucleic acid, a carbohydrate, a lipid, or other molecule. Furthermore, a "target" can be, for example, a cell, an organ, or an organism that contains an epitope that can be bound by a binding molecule (e.g., an antibody or antibody-like molecule).

[0072] Both the light and heavy chains of an antibody or antibody-like molecule are classified into regions of structural and functional homology. The terms "constant" and "variable" are used in relation to function, but refer to the specific structure of the molecule. The variable regions of both the light (VL) and heavy (VH) chains determine antigen recognition and specificity. Conversely, the constant domains (e.g. CH1, CH2, CH3 or CH4) of the light (CL) and heavy chains confer biological properties, such as the ability to multimerize, secretion, transplacental transfer, Fc receptor binding, complement fixation, etc. By convention, the numbering of the constant region domains increases as they become more distal from the antigen-binding region or amino-terminus of the antibody. The N-terminal portion is the variable region, the C-terminal portion is the constant region, and the CH3 (or CH4 for IgM) and CL domains actually comprise the carboxy termini of the heavy and light chains, respectively.

[0073] A "full-length IgM antibody heavy chain" is a polypeptide that comprises, from N-terminal to C-terminal direction, an antibody heavy chain variable domain (VH), antibody heavy chain constant domain 1 (CM1 or Cμ1), antibody heavy chain constant domain 2 (CM2 or Cμ2), antibody heavy chain constant domain 3 (CM3 or Cμ3), and antibody heavy chain constant domain 4 (CM4 or Cμ4), which may include the μ tailpiece.

[0074] As shown above, the variable region(s) form the antigen-binding domain of an antibody or antibody-like molecule, allowing it to selectively recognize and specifically bind to an epitope on an antigen. That is, the VL domain and the VH domain, or the antigen-binding subset of the complementarity determining regions (CDRs) of a binding molecule (e.g., an antibody or antibody-like molecule), combine to form the antigen-binding domain. More specifically, the antigen-binding domain may be defined by the CDRs, three on each of the VH and VL chains. Certain antibodies or antibody-like molecules form larger structures. For example, an IgA heavy chain may form a molecule that includes two or four H2L2 binding units and a J chain covalently linked via disulfide bonds, which may further associate with a secretory component, and an IgM heavy chain may form a pentameric or hexameric molecule that includes five or six H2L2 binding units and optionally a J chain covalently linked via disulfide bonds.

[0075] The six "complementarity determining regions" or "CDRs" present in the antigen-binding domain of an antibody are short, non-contiguous sequences of amino acids that are specifically arranged to form the antigen-binding domain when the antibody assumes its three-dimensional configuration in an aqueous environment. The remaining amino acids in the antigen-binding domain are referred to as "framework" regions and show less variability between molecules. The framework regions adopt a predominantly β-sheet conformation, and the CDRs form loops that connect, and in some cases form part of, the β-sheet structure. Thus, the framework regions act to form a scaffold that provides for the positioning of the CDRs in the correct orientation by non-covalent interactions between the chains. The antigen-binding domain formed by the positioned CDRs defines a surface that is complementary to the epitope on the target antigen. This complementary surface promotes the non-covalent binding of the antibody to its cognate epitope. The amino acids that constitute the CDRs and framework regions, respectively, have been defined in a variety of different ways and can be readily identified by one of skill in the art for any given heavy or light chain variable region (see, e.g., "Sequences of Proteins of Immunological Interest," Kabat, E., et al., USDepartment of Health and Human Services, (1983); and Chothia and Lesk, J. Mol. Biol., 196:901-917 (1987), which are incorporated by reference in their entireties.

[0076] In cases where there is more than one definition of a term used and / or accepted in the art, the definition of the term as used herein is intended to include all such meanings, unless expressly stated otherwise. A specific example is the use of the term "complementarity determining region" ("CDR") to refer to the discontinuous antigen-binding sites found within the variable regions of both heavy and light chain polypeptides. These particular regions are described, for example, by Kabat et al., USDept. of Health and Human Services, "Sequences of Proteins of Immunological Interest" (1983) and Chothia et al., J. Mol. Biol. 196:901-917 (1987), which are incorporated herein by reference. The Kabat and Chothia definitions include overlapping or subsets of amino acids when compared to each other. Nevertheless, application of either definition (or other definitions known to those of skill in the art) to refer to the CDRs of an antibody or variants thereof is intended to be within the scope of the term as defined and used herein, unless otherwise indicated. The appropriate amino acids which encompass the CDRs as defined by each of the above cited references are set forth below in Table 1 for comparison. The exact amino acid numbers which encompass a particular CDR will vary depending on the sequence and size of the CDR. One of skill in the art can routinely determine which amino acids constitute a particular CDR given the variable region amino acid sequence of an antibody.

[0077] Table 1: CDR definitions * TIFF2025506341000002.tif36128 * The numbering of all CDR definitions in Table 1 follows the numbering convention set out by KABAT et al. (see below).

[0078] Antibody variable domains can also be analyzed using, for example, the IMGT information system (imgt_dot_cines_dot_fr / ) (IMGT® / V-Quest) to identify variable region segments containing the CDRs (see, for example, Brochet et al., Nucl. Acids Res., 36:W503-508, 2008).

[0079] Kabat et al. also defined a numbering system for variable and constant region sequences that is applicable to any antibody. One of skill in the art can unambiguously assign this system of "Kabat numbering" to any variable region sequence without reliance on any experimental data beyond the sequence itself. As used herein, "Kabat numbering" refers to the numbering system set forth by Kabat et al., USDept. of Health and Human Services, "Sequence of Proteins of Immunological Interest" (1983). However, all amino acid sequences in this disclosure use consecutive numbering unless the use of the Kabat numbering system is explicitly stated.

[0080] The Kabat numbering system for the human IgM constant domain can be found in Kabat, et al. "Tabulation and Analysis of Amino acid and nucleic acid Sequences of Precursors, V-Regions, C-Regions, J-Chain, T-Cell Receptors for Antigen, T-Cell Surface Antigens, β-2 Microglobulins, Major Histocompatibility Antigens, Thy-1, Complement, C-Reactive Protein, Thymopoietin, Integrins, Post-gamma Globulin, α-2 Macroglobulins, and Other Related Proteins," US Dept. of Health and Human Services (1991). The IgM constant region can be numbered sequentially (i.e., amino acid number 1 starts with the first amino acid of the constant region) or by using the Kabat numbering system. The sequential numbering of the two alleles of the human IgM constant region (SEQ ID NO:1 (allele IGHM * 03) and SEQ ID NO:2 (allele IGHM * A comparison of the numbering according to the Kabat system with that according to the nucleotide sequence 04) (presented herein as 04) is shown below. The underlined amino acid residues are not considered in the Kabat system (the double underlined "X" below can be serine (S) (SEQ ID NO:1) or glycine (G) (SEQ ID NO:2)).

[0081] Sequential (SEQ ID NO:1 or SEQ ID NO:2) / KABAT numbering legend for IgM heavy chain TIFF2025506341000003.tif62145

[0082] Binding molecules, such as antibodies, antibody-like molecules, antigen-binding fragments thereof, variants or derivatives, and / or multimerizable fragments thereof, include, but are not limited to, polyclonal antibodies, monoclonal antibodies, human antibodies, humanized antibodies or chimeric antibodies, single chain antibodies, epitope-binding fragments, such as Fab, Fab' and F(ab')2, Fd, Fvs, single chain Fvs (scFv), single chain antibodies, disulfide-linked Fvs (sdFv), fragments comprising either the VL or VH domain, fragments produced by a Fab expression library. scFv molecules are described, for example, in U.S. Patent No. 5,892,019.

[0083] "Specifically binds" generally means that a binding molecule, such as an antibody or antibody-like molecule, binds to an epitope through its antigen-binding domain, and that binding requires some complementarity between the antigen-binding domain and the epitope. According to this definition, a binding molecule, such as an antibody or antibody-like molecule, is said to "specifically bind" to an epitope if it binds to the epitope through its antigen-binding domain more readily than it binds to a random, unrelated epitope. The term "specificity" is used herein to qualify the relative affinity with which a particular binding molecule binds to a particular epitope. For example, binding molecule "A" may be considered to be more specific for a given epitope than binding molecule "B," or it may be said that binding molecule "A" binds to epitope "C" with higher specificity than it has for related epitope "D."

[0084] The binding molecules disclosed herein, such as antibodies or fragments, variants or derivatives thereof, can be used to bind to cells of up to 5×10 -2 seconds -1 , 10 -2 seconds -1 , 5×10 -3 seconds -1 , 10 -3 seconds -1 , 5×10 -4 seconds -1 , 10 -4 seconds -1, 5×10 -5 seconds -1 , 10 -5 seconds -1 , 5×10 -6 seconds -1 , 10 -6 seconds -1 , 5×10 -7 seconds -1 or 10 -7 seconds -1 It can be expressed as binding to a target antigen with an off-rate (k(off)) of:

[0085] The binding molecules disclosed herein, such as antibodies or antibody-like molecules, can be used in a variety of applications, including: 3 M -1 seconds -1 , 5×10 3 M -1 seconds -1 , 10 4 M -1 seconds -1 , 5×10 4 M -1 seconds -1 , 10 5 M -1 seconds -1 , 5×10 5 M -1 seconds -1 , 10 6 M -1 seconds -1 , 5×10 6 M -1 seconds -1 or 10 7 M -1 seconds -1 It can be expressed as binding to a target antigen with an on rate (k(on)) equal to or greater than this.

[0086] A binding molecule, such as an antibody or antibody-like molecule, is said to competitively inhibit the binding of a reference antibody or antibody-like molecule to a given epitope if it preferentially binds to that epitope to such an extent that it blocks the binding of the reference antibody or antigen-binding fragment to that epitope to some extent. Competitive inhibition can be determined by any method known in the art, such as competitive ELISA assay or OCTET assay. A binding molecule can be said to competitively inhibit the binding of a reference antibody or antibody-like molecule to a given epitope by at least 90%, at least 80%, at least 70%, at least 60% or at least 50%.

[0087] As used herein, the term "affinity" refers to a measure of the strength of binding between one or more antigen-binding domains (e.g., of an antibody or antibody-like molecule) and an individual epitope. See, e.g., Harlow et al., Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988), pages 27-28. As used herein, the term "avidity" refers to the overall stability of the complex between a population of antigen-binding domains and an antigen. See, e.g., Harlow, pages 29-34. Avidity is related to both the affinity of an individual antigen-binding domain in a population with a particular epitope, as well as the valency of the immunoglobulin and the antigen. For example, the interaction between a bivalent monoclonal antibody and an antigen with a highly repeating epitope structure, such as a polymer, would be one of high avidity. Similarly, the interaction between a multimeric antibody with a valency of 4, 8, 10 or 12 and a population of particular epitopes would be one of high avidity. The interaction between a bivalent monoclonal antibody and a receptor that is present at high density on a cell surface will also be of high avidity.

[0088] The binding molecules disclosed herein, such as antibodies or their fragments, variants or derivatives, can also be described or defined in terms of their cross-reactivity.As used herein, the term "cross-reactivity" refers to the ability of a binding molecule, such as an antibody or its fragments, variants or derivatives, that is specific for one antigen to react with another antigen, and is a measure of the closeness between two different antigenic substances.Thus, a binding molecule is cross-reactive if it binds to an epitope other than the epitope that induced the formation of the binding molecule.Cross-reactive epitopes generally contain many of the same complementary structural features as the induced epitope, and in some cases may actually fit better than the original one.

[0089] Binding molecules, e.g., antibodies or fragments, variants or derivatives thereof, may also be described or specified in terms of their binding affinity to an antigen. For example, a binding molecule may have a binding affinity of 5×10 -2 M, 10 -2 M, 5×10 -3 M, 10 -3 M, 5×10 -4 M, 10 -4 M, 5×10 -5 M, 10 -5 M, 5×10 -6 M, 10 -6 M, 5×10 -7 M, 10 -7 M, 5×10 -8 M, 10 -8 M, 5×10 -9 M, 10 -9 M, 5×10 -10 M, 10 -10 M, 5×10 -11 M, 10 -11 M, 5×10 -12 M, 10 -12 M, 5×10 -13 M, 10 -13 M, 5×10 -14 M, 10 -14 M, 5×10 -15 M or 10 -15 It can bind to the antigen with a dissociation constant, or KD, of less than or equal to M.

[0090] Antigen-binding fragments of the binding molecules or antibodies provided herein (including single chain antibodies or other antigen-binding domains) may be present alone or in combination with one or more of the following: hinge region, CH1, CH2, CH3 or CH4 domain, J chain, or secretory component. Also included are antigen-binding fragments that may include any combination of one or more of the hinge region, CH1, CH2, CH3 or CH4 domain, J chain, or secretory component, and sufficient variable region(s) to bind the antigen. The binding molecules, e.g., antibodies or antibody-like molecules, may be from any animal origin, including birds and mammals. The antibodies may be, for example, human, murine, donkey, rabbit, goat, guinea pig, camel, llama, horse, or chicken antibodies. In another embodiment, the variable region may be of condricthoid origin (e.g., from shark). As used herein, a "human" antibody includes antibodies having the amino acid sequence of a human immunoglobulin, and also includes antibodies isolated from a human immunoglobulin library or from an animal that has been transgenic with one or more human immunoglobulins, optionally capable of expressing endogenous immunoglobulins, some of which are unable to do so, as described below and, for example, in U.S. Patent No. 5,939,598 by Kucherlapati et al. According to embodiments of the present disclosure, the IgM or IgM-like antibodies or IgM-derived binding molecules provided herein may include antigen-binding fragments of antibodies (e.g., scFvs), so long as the IgM or IgM-like antibodies are capable of forming multimers (e.g., hexamers or pentamers).

[0091] As used herein, the term "heavy chain subunit" includes an amino acid sequence derived from an immunoglobulin heavy chain. A binding molecule, e.g., an antibody or antibody-like molecule, that includes a heavy chain subunit can include a VH domain and one or more of a CH1 domain, a hinge (e.g., an upstream, middle and / or downstream hinge region) domain, a CH2 domain, a CH3 domain, a CH4 domain, a μ tailpiece (μtp), or a variant or fragment thereof. For example, a binding molecule, e.g., an antibody, an antibody-like molecule, or a fragment, variant or derivative thereof, can include, in addition to a VH domain, any combination of a CH1 domain, a hinge, a CH2 domain, a CH3 domain, a CH4 domain, or a μ tailpiece (μtp) of one or more antibody isotypes and / or species, without limitation. In certain embodiments, a binding molecule, e.g., an antibody, antibody-like molecule, or a fragment, variant, or derivative thereof, may include, in addition to a VH domain, one or more of the following: CH1 domain, CH2 domain, CH3 domain, CH4 domain, μ tailpiece (μtp) domain, and J chain (for IgM), or one or more of the following: CH1 domain, hinge region, CH2 domain, CH3 domain, α tailpiece (αtp) domain, and J chain (for IgA). Furthermore, a binding molecule, e.g., an antibody or antibody-like molecule, provided in the present disclosure may lack all or a portion of a certain constant region portion, e.g., the CH1 domain, hinge, CH2 domain, or CH3 domain. These domains (e.g., heavy chain subunits) may be modified such that their amino acid sequence differs from that of the original immunoglobulin molecule. According to embodiments of the present disclosure, the IgM or IgM-like antibodies provided herein comprise a sufficient portion of an IgM heavy chain constant region to enable the IgM or IgM-like antibody to form multimers (e.g., hexamers or pentamers), e.g., the IgM heavy chain constant region comprises a "multimerizing fragment" of the IgM heavy chain constant region.

[0092] As used herein, the term "light chain subunit" includes an amino acid sequence derived from an immunoglobulin light chain. A light chain subunit includes at least a VL and may further include a CL (e.g., a Cκ or Cλ) domain.

[0093] Binding molecules, such as antibodies, antibody-like molecules, antigen-binding fragments, variants or derivatives thereof, or multimerizing fragments thereof, may be described or defined in terms of the epitope(s) or portion(s) of the antigen that they recognize or specifically bind. The portion of a target antigen that specifically interacts with the antigen-binding domain of an antibody is an "epitope" or "antigenic determinant." A target antigen may contain a single epitope or more than one epitope, and may contain any number of epitopes depending on the size, conformation and type of antigen.

[0094] As used herein, the term "hinge region" includes the portion of the heavy chain molecule that connects the CH1 domain to the CH2 domain in IgG, IgA, and IgD heavy chains. This hinge region contains approximately 25 amino acids and is flexible, thus allowing the two N-terminal antigen-binding regions to move independently.

[0095] As used herein, the term "disulfide bond" includes a covalent bond formed between two sulfur atoms. The amino acid cysteine ​​contains a thiol group that can form a disulfide bond or crosslink with another thiol group.

[0096] As used herein, the term "chimeric antibody" refers to an antibody in which the immunoreactive region or site is obtained or derived from a first species and the constant region (which may be unmodified, partial, or modified) is obtained from a second species. In some embodiments, the target binding region or site is from a non-human source (e.g., mouse or primate) and the constant region is human.

[0097] The term "multispecific antibody" or "bispecific antibody" refers to an antibody or antibody-like molecule that has antigen-binding domains for two or more different epitopes within a single antibody molecule. Canonical antibody structures as well as other binding molecules can be constructed with two binding specificities.

[0098] As used herein, the term "engineered antibody" refers to an antibody in which the variable domains in the heavy and / or light chains have been altered by at least partial replacement of one or more amino acids in either the CDRs or framework regions. In certain embodiments, the entire CDRs from an antibody with known specificity may be grafted into the framework regions of a heterologous antibody. The replacement CDRs may be from an antibody of the same class, or possibly the same subclass, as the antibody from which the framework region is derived, but the CDRs may also be from an antibody of a different class, for example, an antibody from a different species. An engineered antibody in which one or more "donor" CDRs from a non-human antibody with known specificity are grafted into the framework regions of a human heavy or light chain is referred to herein as a "humanized antibody." In certain embodiments, even though not all CDRs are replaced with complete CDRs from the donor variable region, the donor's antigen binding capacity may still be transferred to the recipient's variable domains. Exemplary methods of humanization are described in U.S. Patent Nos. 5,585,089, 5,693,761, 5,693,762, and 6,180,370.

[0099] As used herein, the term "engineered" includes the manipulation of nucleic acid or polypeptide molecules by synthetic means (e.g., recombinant techniques, in vitro peptide synthesis, enzymatic or chemical peptide, nucleic acid or glycan coupling, or some combination of these techniques).

[0100] As used herein, the terms "linked," "fused," or "fusion," or other grammatical equivalents, may be used interchangeably. These terms refer to the joining of two or more elements or components by any means, including chemical conjugation or recombinant means. An "in-frame fusion" refers to the joining of two or more polynucleotide open reading frames (ORFs) in a manner that maintains the translational reading frame of the original ORFs to form a continuous, longer ORF. Thus, a recombinant fusion protein is a single protein that contains two or more segments that correspond to the polypeptides encoded by the original ORFs (these segments are not normally so joined in nature). The reading frame is thus made continuous throughout the fused segments, but the segments may be physically or spatially separated, for example, by in-frame linker sequences. For example, polynucleotides encoding the CDRs of immunoglobulin variable regions may be fused in frame, but may be separated by polynucleotides encoding at least one immunoglobulin framework region or additional CDR regions, so long as the "fused" CDRs are co-translated as part of a continuous polypeptide. The term "associated," and its grammatical equivalents, refers to the interaction of two or more elements that may function together, be connected or fused, but are in close proximity without being linked in any particular way, e.g., may interact in trans.

[0101] In the context of a polypeptide, a "linear sequence" or "sequence" is the order of amino acids in a polypeptide in the amino-terminal to carboxyl-terminal direction, in which adjacent amino acids in the sequence are contiguous in the primary structure of the polypeptide. A portion of a polypeptide that is "amino-terminal" or "N-terminal" to another portion of the polypeptide is that portion that occurs earlier in the contiguous polypeptide chain. Similarly, a portion of a polypeptide that is "carboxy-terminal" or "C-terminal" to another portion of the polypeptide is that portion that occurs later in the contiguous polypeptide chain. For example, in a typical antibody, the variable domain is "N-terminal" to the constant region, and the constant region is "C-terminal" to the variable domain.

[0102] The term "expression" as used herein refers to the process by which a gene produces a biochemical, e.g., a polypeptide. The process includes any manifestation of the functional presence of a gene in a cell, including, but not limited to, gene knockdown, and both transient and stable expression. It includes, but is not limited to, transcription of a gene into RNA (e.g., messenger RNA (mRNA)) and translation of such mRNA into a polypeptide(s). If the final desired product is a biochemical, expression includes the production of that biochemical, and any precursors. Expression of a gene produces a "gene product." As used herein, a gene product can be either a nucleic acid (e.g., messenger RNA) produced by transcription of a gene, or a polypeptide translated from a transcript. Gene products as described herein further include nucleic acids with post-transcriptional modifications (e.g., polyadenylation) or polypeptides with post-translational modifications (e.g., methylation, glycosylation, addition of lipids, association with other protein subunits, proteolytic cleavage, etc.).

[0103] Terms such as "treat" or "treatment" or "treating" or "alleviate" or "alleviating" refer to therapeutic measures that cure, slow down, alleviate symptoms, and / or halt or delay the progression of an existing diagnosed disease, condition, or disorder. Terms such as "prevent", "prevention", "avoid", "inhibit", and the like refer to prophylactic or preventative measures that prevent the onset of an undiagnosed disease, pathological condition, or disorder of interest. Thus, a "subject in need of treatment" can include a subject who already has a disease, condition, or disorder. The term "subject in need of prevention" refers to a subject who is prone to having a disease, condition, or disorder, and a subject in whom a disease, condition, or disorder is to be prevented.

[0104] As used herein, the "potency" of a therapeutic agent, e.g., a binding molecule, is a measure of the activity of the agent, expressed in terms of the amount required to produce a desired biological effect, either in vitro or in vivo. Potency can be expressed, for example, as the concentration or amount of a given therapeutic agent required to affect, e.g., kill, 50% of test cells in an in vitro assay, e.g., complement-dependent cytotoxicity (CDC) or T-cell dependent cytotoxicity assay (TDCC). This measurement can be expressed as a median effective concentration (EC50) or median inhibitory concentration (IC50). Potency can also be expressed as a curve with the % viability or % killing of test cells on the Y-axis and the binding molecule concentration (e.g., in μg / ml or in μM) on the X-axis. "Potency" can also define the ability of a given therapeutic agent to treat a disease or condition in a subject, e.g., an in vivo test animal or a human patient. "Potency" is often used to compare various therapeutic agents in a given assay or experiment, e.g., to show that a particular therapeutic agent is superior to other therapeutic agents with a similar or identical mechanism of action. Effector cell-engaging molecules, e.g., T cell-engaging molecules, provided herein, can have one or more tumor-targeting binding domains, e.g., CD38 binding domains, and one or more effector cell-engaging binding domains, e.g., CD3 binding domains, and thus the molecule as a whole can have at least two potency measurements, one for the ability of the molecule to bind to and kill tumor cells, e.g., by antibody-dependent cellular cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC), and one for the ability of the molecule to engage and activate effector cells, e.g., by T cell-dependent cytotoxicity (TDCC).

[0105] As used herein, the term "serum half-life" or "plasma half-life" refers to the time (e.g., in minutes, hours or days) it takes for the serum or plasma concentration of a protein or drug, e.g., a binding molecule, antibody or antibody-like molecule described herein, to be reduced by 50% after administration. Two half-lives may be described: the alpha half-life, α half-life or t half-life, which is the rate of decline in plasma concentration due to the process of drug redistribution from the central compartment (e.g., blood in the case of intravenous delivery) to the peripheral compartment (e.g., tissue or organ). 1 / 2 The α half-life, which is the rate of decline due to excretory or metabolic processes, and the β half-life or t 1 / 2 β.

[0106] As used herein, the term "area under the plasma drug concentration-time curve" or "AUC" reflects the actual body exposure to a drug after administration of a dose of the drug and is expressed in mg*h / L. This area under the curve is measured from time 0 (t0) to infinity (∞) and depends on the rate of elimination of the drug from the body and the dose administered.

[0107] As used herein, the term "mean residence time" or "MRT" refers to the average length of time that a drug remains in the body.

[0108] "Subject" or "individual" or "animal" or "patient" or "mammal" means any mammalian subject for which diagnosis, prognosis, or treatment is desired. Mammalian subjects include humans, farm animals, livestock, and zoo animals, sport animals, or pets, such as dogs, cats, guinea pigs, rabbits, rats, mice, horses, pigs, cows, bears, etc.

[0109] CD38 target CD38, also known as ADP-ribosyl cyclase / cyclic ADP-ribose hydrolase 1, is a type II single-pass transmembrane protein. It has several known functions, including as an ADP-ribosyl cyclase, a cyclic ADP-ribosyl (cADPr) hydrolase, and a non-canonical receptor. The amino acid sequence of human CD38 is shown as SEQ ID NO: 14, and the amino acid sequence of cynomolgus monkey CD38 is shown as SEQ ID NO: 15 (which is about 93% identical to human CD38). Human CD38 has a cytoplasmic domain from amino acids 1-21 of SEQ ID NO: 14, a transmembrane domain from amino acids 22-42 of SEQ ID NO: 14, and an extracellular domain from amino acids 43-300 of SEQ ID NO: 14.

[0110] Anti-CD38 antigen-binding domain Provided herein are binding molecules, e.g., antibodies or antibody-like molecules, that comprise an antigen-binding domain that specifically binds to CD38, e.g., multimeric antibodies comprising two, four, five, or six bivalent binding units, each binding unit comprising two IgM or IgA heavy chain constant regions, or multimerizing fragments or variants thereof, each associated with an antigen-binding domain.In certain embodiments, the antigen binding domain comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL comprise six immunoglobulin complementarity determining regions HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3, wherein HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are set forth in SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO: SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:73, SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:81, SEQ ID NO:82, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, No. 109, SEQ ID NO: 110 and SEQ ID NO: 111; SEQ ID NO: 113, SEQ ID NO: 114, SEQ ID NO: 115, SEQ ID NO: 117, SEQ ID NO: 118 and SEQ ID NO: 119; SEQ ID NO: 121, SEQ ID NO: 122, SEQ ID NO: 123, SEQ ID NO: 125, SEQ ID NO: 126 and SEQ ID NO: 127; SEQ ID NO: 65, SEQ ID NO: 134, SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70 and SEQ ID NO: 71; SEQ ID NO: 65, SEQ ID NO: 182, SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70 and SEQ ID NO: 71; SEQ ID NO: 65, SEQ ID NO: 134, SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70 and SEQ ID NO: 71; SEQ ID NO: 136, SEQ ID NO: 138, SEQ ID NO: 139, SEQ ID NO: 140 and SEQ ID NO: 141; 35, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:143, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:144, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:145, SEQ ID NO:94 and SEQ ID NO:95; or SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95.

[0111] In some embodiments, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 respectively comprise the amino acid sequences of SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70 and SEQ ID NO: 71. In some embodiments, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 respectively comprise the amino acid sequences of SEQ ID NO: 89, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 93, SEQ ID NO: 94 and SEQ ID NO: 95.

[0112] In some embodiments, the VH further comprises framework regions (HFW) HFW1, HFW2, HFW3 and HFW4, and the VL further comprises framework regions (LFW) LFW1, LFW2, LFW3 and LFW4. In some embodiments, the framework regions are derived from a human antibody. In some embodiments, the framework regions are derived from a non-human antibody. The amino acids that each constitute a framework region can be readily identified by one of skill in the art for any given heavy or light chain variable region, since they are structurally defined in a variety of different ways (see "Sequences of Proteins of Immunological Interest," Kabat, E., et al., USDepartment of Health and Human Services, (1983), and Chothia and Lesk, J. Mol. Biol., 196:901-917 (1987), which are incorporated by reference in their entireties).

[0113] In some embodiments, the VH and VL are, respectively, SEQ ID NO:128 and SEQ ID NO:133; SEQ ID NO:56 and SEQ ID NO:60; SEQ ID NO:64 and SEQ ID NO:68; SEQ ID NO:72 and SEQ ID NO:76; SEQ ID NO:80 and SEQ ID NO:84; SEQ ID NO:88 and SEQ ID NO:92; SEQ ID NO:96 and SEQ ID NO:100; SEQ ID NO:104 and SEQ ID NO:108; SEQ ID NO:112 and SEQ ID NO:116; SEQ ID NO:120 and SEQ ID NO:124; SEQ ID NO:128 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:133; SEQ ID NO:130 and SEQ ID NO:68; SEQ ID NO:130 and SEQ ID NO:133; SEQ ID NO:131 and SEQ ID NO:68; SEQ ID NO:131 and SEQ ID NO:133; SEQ ID NO:132 and SEQ ID NO:68; SEQ ID NO:132 and SEQ ID NO:133; SEQ ID NO:64 and SEQ ID NO: SEQ ID NO:133; SEQ ID NO:136 and SEQ ID NO:86; SEQ ID NO:136 and SEQ ID NO:138; SEQ ID NO:136 and SEQ ID NO:139; SEQ ID NO:136 and SEQ ID NO:140; SEQ ID NO:136 and SEQ ID NO:141; SEQ ID NO:136 and SEQ ID NO:142; SEQ ID NO:137 and SEQ ID NO:86; SEQ ID NO:137 and SEQ ID NO:138; SEQ ID NO:137 and SEQ ID NO:139; SEQ ID NO:137 and SEQ ID NO:140; SEQ ID NO:137 and SEQ ID NO:141; SEQ ID NO:137 and SEQ ID NO:142; SEQ ID NO:88 and SEQ ID NO:138; SEQ ID NO:88 and SEQ ID NO:139; SEQ ID NO:88 and SEQ ID NO:140; SEQ ID NO:88 and SEQ ID NO:141; or SEQ ID NO:88 and SEQ ID NO:142. In some embodiments, VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO: 128 and SEQ ID NO: 133, respectively. In some embodiments, VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO: 136 and SEQ ID NO: 138, respectively.

[0114] In certain embodiments, the VH and VL are, respectively, SEQ ID NO:147 and SEQ ID NO:150; SEQ ID NO:147 and SEQ ID NO:151; SEQ ID NO:147 and SEQ ID NO:152; SEQ ID NO:147 and SEQ ID NO:153; SEQ ID NO:147 and SEQ ID NO:154; SEQ ID NO:147 and SEQ ID NO:155; SEQ ID NO:148 and SEQ ID NO:150; SEQ ID NO:148 and SEQ ID NO:151; SEQ ID NO:148 and SEQ ID NO:152; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:154; SEQ ID NO:148 and SEQ ID NO:155; SEQ ID NO:149 and SEQ ID NO:150; SEQ ID NO:149 and SEQ ID NO:151; SEQ ID NO:149 and SEQ ID NO:152; SEQ ID NO:149 and SEQ ID NO:153; SEQ ID NO:149 and SEQ ID NO:154; SEQ ID NO:149 and SEQ ID NO:155; SEQ ID NO:156 and SEQ ID NO:159; SEQ ID NO:156 and SEQ ID NO:160; SEQ ID NO:156 and SEQ ID NO:161; SEQ ID NO:157 and SEQ ID NO:159; SEQ ID NO:157 and SEQ ID NO:160; SEQ ID NO:157 and SEQ ID NO:161; SEQ ID NO:158 and SEQ ID NO:159; SEQ ID NO:158 and SEQ ID NO:160; or SEQ ID NO:158 and SEQ ID NO:161.

[0115] In certain embodiments, the antigen-binding domain provided above is an Fv fragment, such as a single chain Fv fragment (scFv) or a disulfide-linked Fv fragment (sdFv). In certain embodiments, the antigen-binding domain provided above is an scFv.

[0116] In certain embodiments, the antigen-binding domains provided above are comprised in an antibody or antibody-like molecule as described elsewhere herein. In some embodiments, the antigen-binding domains provided above are comprised in an antibody or antibody-like molecule that is multispecific, such as bispecific, trispecific, or tetraspecific. In some embodiments, the multispecific antibody or antibody-like molecule provided herein specifically binds to CD38 and to a target on an effector cell, such as CD16 or CD3.

[0117] In certain embodiments, the antibody or antibody-like molecule comprises a bivalent binding unit comprising two antigen-binding domains, at least one of which specifically binds to CD38. According to this embodiment, the binding unit comprises two heavy chains, each of which comprises a heavy chain constant region or a fragment or variant thereof, and at least one of the heavy chain constant regions or a fragment or variant thereof of the binding unit is associated with, e.g., fused to, a copy of the VH of the antigen-binding domain provided herein. In certain embodiments, both heavy chain constant regions or a fragment or variant thereof of the binding unit are associated with, e.g., fused to, a copy of the VH of the antigen-binding domain provided herein. In certain embodiments, the heavy chain comprises an IgG heavy chain constant region or a fragment or variant thereof. Various IgG heavy chain constant regions and fragments or variants thereof are known, including those described in Kang, et al., 2019, Experimental & Molecular Medicine, 51:1-9; Brezski, et al., 2016, Current Opinion in Immunology, 40:62-69; Okazaki, et al., 2004, Journal of Molecular Biology, 336(5):1239-1249; Kang, et al., 2019, Front. Immunol., 10(562):1-11; and Saxena, et al., 2016, Front. Immunol., 7(580):1-11. In certain embodiments, the single bivalent binding unit further comprises two light chains, each of which comprises a light chain constant region or a fragment or variant thereof. In certain embodiments, at least one light chain constant region is associated with, e.g., fused to, a copy of the VL of the antigen-binding domain provided herein.In certain embodiments, both light chain constant regions of the binding unit, or fragments or variants thereof, are associated with, e.g., fused to, a copy of the VL of the antigen-binding domain provided herein.In certain embodiments, the bivalent binding unit comprises a complete antibody, e.g., a complete IgG antibody.In certain embodiments, a single bivalent binding unit comprises a complete IgG antibody comprising two complete IgG heavy chain constant regions.In certain embodiments, the bivalent binding unit is a human IgG antibody, a fragment or derivative thereof.

[0118] In certain embodiments, the provided antigen-binding domains are comprised in a multimeric antibody or antibody-like molecule comprising 2, 4, 5, or 6 bivalent binding units, and the antibody comprises 4, 8, 10, or 12 antigen-binding domains. In certain embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 of the antigen-binding domains specifically bind to CD38. In certain embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 of the antigen-binding domains comprise the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3, and / or VH and VL amino acid sequences provided above. According to these embodiments, each binding unit comprises two heavy chains each comprising an IgA or IgM constant region or a multimerizing fragment or variant thereof, and at least one of the heavy chain constant regions of the binding unit is associated with, e.g., fused to, a copy of the VH of the antigen-binding domain of the present invention. In certain embodiments, the multimeric antibody or antibody-like molecule is a human antibody. In certain embodiments, the multimeric antibody or antibody-like molecule is more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody. In some embodiments, the multimer can induce complement-dependent cytotoxicity (CDC) of CD38-expressing cells with a higher potency than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody.

[0119] In certain embodiments, the provided multimeric antibody or antibody-like molecule is a dimer or tetramer and comprises two or four bivalent IgA binding units and a J chain or a functional fragment or variant thereof, each binding unit comprising two IgA heavy chain constant regions, such as IgA1 or IgA2 heavy chain constant regions, or multimerizing fragments or variants thereof. In certain embodiments, the dimeric or tetrameric antibody or antibody-like molecule may further comprise a secretory component or a fragment or variant thereof. In certain embodiments, each of the IgA heavy chain constant regions or multimerizing fragments or variants thereof comprises a Cα3 domain and an α tailpiece (αtp) domain, and may further comprise a Cα1 domain, a Cα2 domain, an IgA hinge region, or any combination thereof. In certain embodiments, the multimeric antibody or antibody-like molecule is more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and VL of the multimeric antibody.

[0120] In certain embodiments, the provided multimeric antibody or antibody-like molecule is a hexamer or pentamer and comprises 5 or 6 bivalent IgM binding units, each of which comprises two IgM heavy chain constant regions or multimerizing fragments or variants thereof. In certain embodiments, each of the IgM heavy chain constant regions or multimerizing fragments or variants thereof comprises a Cμ4 domain and a μ tailpiece (μtp) domain, and may further comprise a Cμ1 domain, a Cμ2 domain, a Cμ3 domain, or any combination thereof. In certain embodiments, the multimeric antibody antibody-like molecule is a pentamer and further comprises a J chain or a functional fragment or functional variant thereof. In certain embodiments, each binding unit further comprises two light chains, each of which comprises a light chain constant region or a fragment or variant thereof, and at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 light chain constant regions are associated, e.g., fused, to the provided VL copy of the antigen-binding domain. In certain embodiments, the multimeric antibody or antibody-like molecule is a human antibody. In certain embodiments, the multimeric antibody or antibody-like molecule is more potent than an equivalent amount of a bivalent IgG antibody that contains the VH and VL of the multimeric antibody. In some embodiments, the multimer can induce complement-dependent cytotoxicity (CDC) of CD38-expressing cells with higher potency than an equivalent amount of a bivalent IgG antibody that contains the VH and VL of the multimeric antibody.

[0121] The antibodies or antibody-like molecules provided herein can be multispecific in certain embodiments.

[0122] In certain embodiments, the antigen-binding domains provided herein, or antibodies or fragments or derivatives or antibody-like molecules comprising the antigen-binding domains, can specifically bind to human CD38, non-human primate CD38, or any combination thereof. In certain embodiments, the non-human primate CD38 is cynomolgus monkey CD38. In certain embodiments, the provided antigen-binding domain, or an antibody or fragment or derivative comprising the antigen-binding domain, binds to CD38 with an affinity characterized by a dissociation constant KD of less than or equal to 500 nM, 100 nM, 50.0 nM, 40.0 nM, 30.0 nM, 20.0 nM, 10.0 nM, 9.0 nM, 8.0 nM, 7.0 nM, 6.0 nM, 5.0 nM, 4.0 nM, 3.0 nM, 2.0 nM, 1.0 nM, 0.50 nM, 0.10 nM, 0.050 nM, 0.01 nM, 0.005 nM, or 0.001 nM, wherein CD38 is human CD38, cynomolgus monkey CD38, or a combination thereof.

[0123] IgM antibodies, IgM-like antibodies and IgM-derived binding molecules IgM is the first immunoglobulin produced by B cells in response to stimulation with an antigen and is naturally present in serum at approximately 1.5 mg / ml with a half-life of about 5 days. IgM is a pentameric or hexameric molecule and therefore contains 5 or 6 binding units. An IgM binding unit typically contains two light chains and two heavy chains. The IgG heavy chain constant region contains three heavy chain constant domains (CH1, CH2 and CH3), whereas the heavy chain (μ) constant region of IgM contains an additional fourth constant domain (CH4) and includes a C-terminal μ "tailpiece" (μtp). Although multiple human alleles exist, the human IgM constant region is typically represented by SEQ ID NO: 1 (IMGT allele IGHM * 03, e.g., identical to GenBank accession number pir||S37768) or SEQ ID NO: 2 (IMGT allele IGHM *04, e.g., identical to GenBank Accession No. sp|P01871.4). The human Cμ1 region ranges from about amino acid 5 to about amino acid 102 of SEQ ID NO:1 or SEQ ID NO:2, the human Cμ2 region ranges from about amino acid 114 to about amino acid 205 of SEQ ID NO:1 or SEQ ID NO:2, the human Cμ3 region ranges from about amino acid 224 to about amino acid 319 of SEQ ID NO:1 or SEQ ID NO:2, the Cμ4 region ranges from about amino acid 329 to about amino acid 430 of SEQ ID NO:1 or SEQ ID NO:2, and the tailpiece ranges from about amino acid 431 to about amino acid 453 of SEQ ID NO:1 or SEQ ID NO:2.

[0124] Other forms of the human IgM constant region exist with minor sequence variations, including, but not limited to, GenBank Accession Nos. CAB37838.1 and pir||MHHU. Similarly, amino acid substitutions, insertions and / or deletions at positions corresponding to SEQ ID NO:1 or SEQ ID NO:2 described and claimed elsewhere in this disclosure can be incorporated into alternative human IgM sequences, and IgM constant region amino acid sequences of other species.

[0125] Each IgM heavy chain constant region is typically associated with an antigen-binding domain, such as an scFv, or a subunit of an antigen-binding domain, such as a VH region.

[0126] Five IgM binding units may complex with an additional small polypeptide chain (J chain) or a functional fragment, variant or derivative thereof to form a pentameric IgM or IgM-like antibody. The precursor form of the human J chain is shown as SEQ ID NO:6. The signal peptide extends from amino acid 1 to about amino acid 22 of SEQ ID NO:6, and the mature human J chain extends from about amino acid 23 to amino acid 159 of SEQ ID NO:6. The mature human J chain has the amino acid sequence of SEQ ID NO:7.

[0127] Exemplary variants and modified J chains are provided elsewhere herein. In the absence of a J chain, an IgM or IgM-like antibody typically assembles into a hexamer comprising six binding units and up to 12 antigen-binding domains associated with the binding units. In the presence of a J chain, an IgM or IgM-like antibody typically assembles into a pentamer comprising up to 10 antigen-binding domains associated with five binding units, or larger if the J chain is a modified J chain comprising one or more heterologous polypeptides that may be, for example, additional J chain-associated antigen-binding domain(s). The assembly of five or six IgM binding units into a pentameric or hexameric IgM or IgM-like antibody is believed to involve interactions between the Cμ4 and μ tailpiece domains. See, e.g., Braathen, R., et al., J. Biol. Chem. 277:42755-42762 (2002). Thus, the constant region of a pentameric or hexameric IgM antibody or antibody-like molecule provided in the present disclosure typically comprises at least the Cμ4 and / or μ tailpiece (μtp) domains. Thus, a "multimerizing fragment" of an IgM heavy chain constant region comprises at least the Cμ4 and μtp domains. The IgM heavy chain constant region may additionally comprise a Cμ3 domain or fragment thereof, a Cμ2 domain or fragment thereof, and / or a Cμ1 domain or fragment thereof. In certain embodiments, a binding molecule provided herein, such as an IgM antibody or IgM-like antibody, may comprise the complete IgM heavy chain (μ chain) constant domain (e.g., SEQ ID NO: 1 or SEQ ID NO: 2) or a multimerizing variant, derivative, or analog thereof, such as those provided herein.

[0128] In certain embodiments, the present disclosure provides a pentameric IgM or IgM-like antibody comprising five bivalent binding units, each of which comprises two IgM heavy chain constant regions, or multimerizing fragments or variants thereof, each associated with an antigen-binding domain or a subunit of an antigen-binding domain, in certain embodiments, the two IgM heavy chain constant regions are human heavy chain constant regions.

[0129] When the IgM or IgM-like antibody provided herein is a pentamer, the IgM or IgM-like antibody typically further comprises a J chain or a functional fragment or variant thereof. In some embodiments, the J chain is a modified J chain that comprises a heterologous moiety, such as a J chain-associated antigen-binding domain. In certain embodiments, the J chain-associated antigen-binding domain specifically binds to immune effector cells (e.g., CD8+ cytotoxic T cells or NK cells). In certain embodiments, the modified J chain comprises one or more heterologous moieties, such as immunostimulatory agents, attached thereto. In certain embodiments, the J chain may be mutated to affect, e.g., extend, the serum half-life of the IgM or IgM-like antibody provided herein, as discussed elsewhere in this disclosure. In certain embodiments, the J chain may be mutated to affect glycosylation, as discussed elsewhere in this disclosure.

[0130] In some embodiments, the IgM or IgM-like antibodies provided herein are hexamers and contain six bivalent binding units, in some embodiments, each binding unit contains two IgM heavy chain constant regions or multimerizing fragments or variants thereof.

[0131] An IgM heavy chain constant region may comprise one or more of a Cμ1 domain or a fragment or variant thereof, a Cμ2 domain or a fragment or variant thereof, a Cμ3 domain or a fragment or variant thereof, a Cμ4 domain or a fragment or variant thereof, and / or a μ tailpiece (μtp) or a fragment or variant thereof, provided that the constant region is capable of providing the desired function in an IgM or IgM-like antibody, e.g., capable of associating with another IgM constant region to form a binding unit having one, two or more antigen binding domain(s) and / or capable of associating with other binding units (and further J chains in the case of pentamers) to form hexamers or pentamers. In certain embodiments, the two IgM heavy chain constant regions or fragments or variants thereof in an individual binding unit each comprise a Cμ4 domain or a fragment or variant thereof, a μ tailpiece (μtp) or a fragment or variant thereof, or a combination of a Cμ4 domain and a μtp or a fragment or variant thereof. In certain embodiments, the two IgM heavy chain constant regions or fragments or variants thereof in an individual binding unit each further comprises a Cμ3 domain or fragment or variant thereof, a Cμ2 domain or fragment or variant thereof, a Cμ1 domain or fragment or variant thereof, or any combination thereof.

[0132] In some embodiments, the binding units of an IgM or IgM-like antibody comprise two light chains. In some embodiments, the binding units of an IgM or IgM-like antibody comprise fragments of two light chains. In some embodiments, the light chains are kappa light chains. In some embodiments, the light chains are lambda light chains. In some embodiments, the light chains are hybrid kappa-lambda light chains. In some embodiments, each binding unit comprises two immunoglobulin light chains, each comprising a VL located amino-terminally of an immunoglobulin light chain constant region.

[0133] IgM ANTIBODIES, IgM-LIKE ANTIBODIES AND IgM-DERIVED BINDING MOLECULES WITH EXTENDED SERUM HALF-LIFE - Patent application Certain IgM-derived polymeric binding molecules, such as antibodies or antibody-like molecules, provided herein may be modified to have an extended serum half-life. Exemplary IgM heavy chain constant region mutations that can extend the serum half-life of IgM-derived binding molecules are disclosed in U.S. Patent No. 10,899,835, which is incorporated herein by reference in its entirety. For example, the variant IgM heavy chain constant region of the IgM-derived binding molecules provided herein may contain amino acid substitutions at amino acid positions corresponding to amino acids S401, E402, E403, R344 and / or E345 of the wild-type human IgM constant region (e.g., SEQ ID NO: 1 or SEQ ID NO: 2). "Amino acids corresponding to amino acids S401, E402, E403, R344 and / or E345 of the wild-type human IgM constant region" means amino acids in the sequence of an IgM constant region of any species that are homologous to S401, E402, E403, R344 and / or E345 in the human IgM constant region. In certain embodiments, the amino acids corresponding to S401, E402, E403, R344 and / or E345 of SEQ ID NO:1 or SEQ ID NO:2 can be substituted with any amino acid, for example alanine.

[0134] IgM ANTIBODIES, IgM-LIKE ANTIBODIES AND IgM-DERIVED BINDING MOLECULES WITH REDUCED CDC ACTIVITY Certain IgM-derived multimeric binding molecules, e.g., antibodies or antibody-like molecules, provided herein can be engineered to exhibit reduced complement-dependent cytotoxicity (CDC) activity against cells in the presence of complement, compared to a reference IgM antibody or IgM-like antibody having a corresponding reference human IgM constant region that is identical except for the mutations that confer reduced CDC activity. These CDC mutations can be combined with any of the mutations that block N-linked glycosylation and / or confer increased serum half-life, as provided herein. A "corresponding reference human IgM constant region" refers to a human IgM constant region or portion thereof (e.g., Cμ3 domain) that is identical to the variant IgM constant region except for the modification(s) in the constant region that affect CDC activity. In certain embodiments, the variant human IgM constant region contains one or more amino acid substitutions, e.g., in the Cμ3 domain, compared to a wild-type human IgM constant region, e.g., as described in U.S. Patent Publication No. 2021 / 0147567, which is incorporated herein by reference in its entirety. Assays for measuring CDC are well known to those of skill in the art, and exemplary assays are described, for example, in U.S. Patent Application Publication No. 2021-0147567, which is incorporated by reference in its entirety into this specification.

[0135] In certain embodiments, the variant human IgM constant region that confers reduced CDC activity is SEQ ID NO: 1 of the wild-type human IgM constant region (human IgM constant region allele IGHM * 03) or SEQ ID NO:2 (human IgM constant region allele IGHM *04) of position L310, P311, P313 and / or K315. In certain embodiments, a variant human IgM constant region that confers reduced CDC activity comprises an amino acid substitution corresponding to position P311 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region. In other embodiments, a variant IgM constant region provided herein contains an amino acid substitution corresponding to at position P313 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region. In other embodiments, a variant IgM constant region provided herein contains a combination of substitutions corresponding to position P311 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region, and / or P313 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region. These proline residues may be independently replaced with any amino acid, e.g., alanine, serine, or glycine. In certain embodiments, a variant human IgM constant region that confers reduced CDC activity comprises an amino acid substitution corresponding to position K315 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region. The lysine residues may be independently substituted with any amino acid, for example, alanine, serine, glycine, or aspartic acid. In certain embodiments, the variant human IgM constant region that confers reduced CDC activity comprises an amino acid substitution corresponding to position K315 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region with aspartic acid. In certain embodiments, the variant human IgM constant region that confers reduced CDC activity comprises an amino acid substitution corresponding to position L310 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region. The lysine residues may be independently substituted with any amino acid, for example, alanine, serine, glycine, or aspartic acid. In certain embodiments, the variant human IgM constant region that confers reduced CDC activity comprises an amino acid substitution corresponding to position L310 of SEQ ID NO: 1 or SEQ ID NO: 2 of the wild-type human IgM constant region with aspartic acid.

[0136] Glycosylated IgM antibodies, IgM-like antibodies and IgM-derived binding molecules Human and certain non-human primate IgM constant regions typically contain five naturally occurring asparagine (N)-linked glycosylation motifs or sites. As used herein, an "N-linked glycosylation motif" comprises or consists of the amino acid sequence N-X1-S / T, where N is asparagine, X1 is any amino acid except proline (P), and S / T is serine (S) or threonine (T). The glycan is attached to the nitrogen atom of the asparagine residue. See, e.g., Drickamer K, Taylor ME (2006), Introduction to Glycobiology (2nd ed.). Oxford University Press, USA. The N-linked glycosylation motifs occur in the human IgM heavy chain constant region of SEQ ID NO:1 or SEQ ID NO:2, beginning at positions 46 ("N1"), 209 ("N2"), 272 ("N3"), 279 ("N4"), and 440 ("N5"). These five motifs are conserved in non-human primate IgM heavy chain constant regions, and four of the five are conserved in mouse IgM heavy chain constant regions. Thus, in some embodiments, the IgM heavy chain constant region of the multimeric binding molecules provided herein comprises five N-linked glycosylation motifs: N1, N2, N3, N4, and N5. In some embodiments, at least three of the N-linked glycosylation motifs (e.g., N1, N2, and N3) on each IgM heavy chain constant region are occupied by complex glycans.

[0137] In certain embodiments, at least one, at least two, at least three, or at least four of the N-X1-S / T motifs may contain an amino acid insertion, deletion, or substitution that prevents glycosylation at that motif. In certain embodiments, the IgM-derived multimeric binding molecule may contain an amino acid insertion, deletion, or substitution in motif N1, motif N2, motif N3, motif N5, or in any combination of two or more, three or more, or all four of motifs N1, N2, N3, or N5, which amino acid insertion, deletion, or substitution prevents glycosylation at that motif. In some embodiments, the IgM constant region is a variant of SEQ ID NO: 1 (human IgM constant region allele IGHM) compared to the wild-type human IgM constant region. * 03) or SEQ ID NO:2 (human IgM constant region allele IGHM * 04) at positions 46, 209, 272 or 440. See, e.g., PCT Publication No. WO2021 / 041250, which is incorporated by reference in its entirety.

[0138] IgA antibodies, IgA-like antibodies and IgA-derived binding molecules IgA plays a key role in mucosal immunity and constitutes approximately 15% of all immunoglobulins produced. IgA can be monomeric or polymeric, forming primarily dimeric molecules, but also assembling as trimers, tetramers, and / or pentamers. See, e.g., de Sousa-Pereira, P., and JM Woof, Antibodies 8:57 (2019).

[0139] In some embodiments, the multimeric binding molecule is a dimer and comprises two bivalent binding units or variants or fragments thereof. In some embodiments, the multimeric binding molecule is a dimer or tetramer comprising two or four bivalent binding units or variants or fragments thereof, respectively, and further comprises a J chain or functional fragment or variant thereof as described herein. In some embodiments, the multimeric binding molecule is a dimer and comprises two bivalent binding units or variants or fragments thereof, and further comprises a J chain or functional fragment or variant thereof as described herein, each binding unit comprising two IgA heavy chain constant regions or multimerizing fragments or variants thereof.

[0140] In some embodiments, the polymeric binding molecule is a tetramer and comprises four bivalent binding units or variants or fragments thereof. In some embodiments, the polymeric binding molecule is a tetramer and comprises four bivalent binding units or variants or fragments thereof, and further comprises a J chain or functional fragment or variant thereof as described herein. In some embodiments, the polymeric binding molecule is a tetramer and comprises four bivalent binding units or variants or fragments thereof, and further comprises a J chain or functional fragment or variant thereof as described herein, each binding unit comprising two IgA heavy chain constant regions or multimerizing fragments or variants thereof.

[0141] In certain embodiments, the multimeric binding molecules provided by the present disclosure are dimeric binding molecules that include four IgA heavy chain constant regions or multimerizing fragments thereof, each associated with an antigen binding domain for a total of four antigen binding domains. As provided herein, the dimeric IgA antibody, IgA-derived binding molecule, or IgA-like antibody includes two binding units and a J chain, e.g., a modified J chain that includes an scFv antibody fragment that binds to CD3 or includes an IL-15 and / or IL-15 receptor-α sushi domain fused thereto, as described elsewhere herein. Each binding unit provided herein includes two IgA heavy chain constant regions or multimerizing fragments or variants thereof. In certain embodiments, at least three or all four antigen binding domains of the multimeric binding molecule bind to the same target antigen. In certain embodiments, at least three or all four binding polypeptides of the multimeric binding molecule are identical.

[0142] A bivalent IgA-derived binding unit comprises two IgA heavy chain constant regions, and a dimeric IgA-derived binding molecule comprises two binding units. IgA contains the following heavy chain constant domains: Cα1 (or alternatively CA1 or CH1), hinge region, Cα2 (or alternatively CA2 or CH2), and Cα3 (or alternatively CA3 or CH3), and a C-terminal "tailpiece". Human IgA has two subtypes: IgA1 and IgA2. The human IgA1 constant region typically comprises the amino acid sequence of SEQ ID NO:3. The human Cα1 domain extends from about amino acid 6 to about amino acid 98 of SEQ ID NO:3, the human IgA1 hinge region extends from about amino acid 102 to about amino acid 124 of SEQ ID NO:3, the human Cα2 domain extends from about amino acid 125 to about amino acid 219 of SEQ ID NO:3, the human Cα3 domain extends from about amino acid 228 to about amino acid 330 of SEQ ID NO:3, and the tailpiece extends from about amino acid 331 to about amino acid 352 of SEQ ID NO:3. The human IgA2 constant region typically comprises the amino acid sequence of SEQ ID NO:4. The human Cα1 domain extends from about amino acid 6 to about amino acid 98 of SEQ ID NO:4, the human IgA2 hinge region extends from about amino acid 102 to about amino acid 111 of SEQ ID NO:4, the human Cα2 domain extends from about amino acid 113 to about amino acid 206 of SEQ ID NO:4, the human Cα3 domain extends from about amino acid 215 to about amino acid 317 of SEQ ID NO:4, and the tailpiece extends from about amino acid 318 to about amino acid 340 of SEQ ID NO:4.

[0143] Two IgA binding units can be complexed with two additional polypeptide chains, a J chain (e.g., SEQ ID NO: 7) and a secretory component (precursor SEQ ID NO: 5, mature from about amino acid 19 to about amino acid 764 of SEQ ID NO: 5), to form a bivalent secretory IgA (sIgA)-derived binding molecule provided herein. The assembly of two IgA binding units into a dimeric IgA-derived binding molecule is believed to involve the Cα3 and tailpiece domains. See, e.g., Braathen, R., et al., J. Biol. Chem. 277: 42755-42762 (2002). Thus, a multimerizable dimeric IgA-derived binding molecule provided herein typically includes an IgA constant region that includes at least the Cα3 and α tailpiece domains. Four IgA binding units can similarly form a tetrameric complex with a J chain. sIgA antibodies can also form as higher order multimers, e.g., tetramers.

[0144] The IgA heavy chain constant region may additionally comprise a Cα2 domain or a fragment thereof, an IgA hinge region or a fragment thereof, a Cα1 domain or a fragment thereof, and / or other IgA (or other immunoglobulin, e.g., IgG) heavy chain domain, e.g., an IgG hinge region. In certain embodiments, a binding molecule provided herein may comprise a complete IgA heavy chain (α chain) constant domain (e.g., SEQ ID NO: 3 or SEQ ID NO: 4), or a variant, derivative, or analog thereof. In some embodiments, the IgA heavy chain constant region, or a multimerizing fragment thereof, is a human IgA constant region.

[0145] In certain embodiments, each binding unit of the multimeric binding molecules provided herein comprises two IgA heavy chain constant regions, or multimerizing fragments or variants thereof, each comprising at least an IgA Cα3 domain and an IgA tailpiece domain. In certain embodiments, the IgA heavy chain constant regions may each further comprise an IgA Cα2 domain located N-terminal to the IgA Cα3 and IgA tailpiece domains. For example, the IgA heavy chain constant region may comprise amino acids 125-353 of SEQ ID NO: 3, or amino acids 113-340 of SEQ ID NO: 4. In certain embodiments, the IgA heavy chain constant region may each further comprise an IgA or IgG hinge region located N-terminal to the IgA Cα2 domain. For example, the IgA heavy chain constant region may comprise amino acids 102-353 of SEQ ID NO: 3, or amino acids 102-340 of SEQ ID NO: 4. In certain embodiments, the IgA heavy chain constant regions can each further comprise an IgA Cα1 domain located N-terminal to the IgA hinge region.

[0146] In some embodiments, each binding unit of an IgA antibody, an IgA-like antibody, or other IgA-derived binding molecule comprises two light chains. In some embodiments, each binding unit of an IgA antibody, an IgA-like antibody, or other IgA-derived binding molecule comprises fragments of two light chains. In some embodiments, the light chain is a kappa light chain. In some embodiments, the light chain is a lambda light chain. In some embodiments, the light chain is a chimeric kappa-lambda light chain. In some embodiments, each binding unit comprises two immunoglobulin light chains, each comprising a VL located amino-terminal to an immunoglobulin light chain constant region.

[0147] Modified and / or variant J chains In certain embodiments, the polymeric binding molecules provided herein, such as antibodies or antibody-like molecules, comprise a J chain, or a functional fragment or variant thereof. In certain embodiments, the polymeric binding molecules provided herein are pentameric IgM antibodies or IgM antibody-like molecules and comprise a J chain, or a functional fragment or variant thereof. In certain embodiments, the polymeric binding molecules provided herein are dimeric IgA antibodies or IgA antibody-like molecules and comprise a J chain, or a functional fragment or variant thereof. In some embodiments, the polymeric binding molecules can comprise a naturally occurring J chain, such as a mature human J chain (e.g., SEQ ID NO: 7). In some embodiments, the polymeric binding molecules can comprise a functional fragment or variant of a naturally occurring J chain.

[0148] In certain embodiments, the J chain of a pentameric IgM or IgM-like antibody or a dimeric IgA or IgA-like antibody provided herein can be modified, for example, by introducing a heterologous moiety or two or more heterologous moieties (e.g., polypeptides) without interfering with the ability of the IgM or IgM-like antibody or IgA or IgA-like antibody to assemble and bind to its binding target(s). See U.S. Patent Nos. 9,951,134, 10,975,147, 10,400,038, and 10,618,978, and U.S. Patent Application Publication No. US-2019-0185570, each of which is incorporated by reference in its entirety. Thus, the IgM or IgM-like antibodies or IgA or IgA-like antibodies provided herein, including the bispecific or multispecific IgM or IgM-like antibodies or IgA or IgA-like antibodies described elsewhere herein, may include a modified J chain or a functional fragment or variant thereof further comprising a heterologous moiety, e.g., a heterologous polypeptide, introduced into the J chain or a fragment or variant thereof. In certain embodiments, the heterologous moiety may be a peptide or polypeptide that is fused in frame or chemically conjugated to the J chain or a fragment or variant thereof. For example, the heterologous polypeptide may be fused to the J chain or a functional fragment or variant thereof. In certain embodiments, the heterologous polypeptide is fused to the J chain or a functional fragment or variant thereof via a linker, e.g., a peptide linker consisting of at least 5 amino acids, but typically consisting of 25 amino acids or less. In certain embodiments, the peptide linker consists of GGGGS (SEQ ID NO:9), GGGGSGGGGS (SEQ ID NO:10), GGGSGGGGSGGGGGS (SEQ ID NO:11), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO:12), or GGGGSGGGGSGGGGSGGGGSGGGGGS (SEQ ID NO:13). In certain embodiments, the heterologous moiety can be a chemical moiety that is conjugated to the J chain.The heterologous moiety attached to the J chain may include, but is not limited to, a binding moiety, such as an antibody or an antigen-binding fragment thereof, such as a single chain Fv (scFv) molecule, a stabilizing peptide capable of extending the half-life of the IgM or IgM-like antibody, or a chemical moiety, such as a polymer or a cytotoxin. In some embodiments, the heterologous moiety comprises a stabilizing peptide capable of extending the half-life of the binding molecule, such as human serum albumin (HSA) or an HSA binding molecule.

[0149] In some embodiments, the modified J chain may comprise a J chain-associated antigen-binding domain (e.g., a polypeptide capable of specifically binding to a target antigen). In certain embodiments, the J chain-associated antigen-binding domain may be an antibody or antigen-binding fragment thereof as described elsewhere herein. In certain embodiments, the J chain-associated antigen-binding domain may be a single chain Fv (scFv) antigen-binding domain or a single chain antigen-binding domain, e.g., derived from a camelid antibody or a cartilaginous fish antibody. The J chain-associated antigen-binding domain may be introduced into the J chain at any position that allows the J chain-associated antigen-binding domain to bind to its binding target without interfering with J chain function or the function of the associated IgM or IgA antibody or antibody-like molecule. Insertion positions include, but are not limited to, at or near the C-terminus, at or near the N-terminus, or at an internal location that is accessible based on the three-dimensional structure of the J chain. In certain embodiments, the J chain-associated antigen-binding domain may be introduced into the mature human J chain of SEQ ID NO:7 between cysteine ​​residues 92 and 101 of SEQ ID NO:7. In a further embodiment, a J chain-associated antigen binding domain may be introduced at or near a glycosylation site in the human J chain of SEQ ID NO: 7. In a further embodiment, a J chain-associated antigen binding domain may be introduced within about 10 amino acid residues from the C-terminus, or within about 10 amino acids from the N-terminus, in the human J chain of SEQ ID NO: 7. As described elsewhere herein, the present disclosure provides multimeric bispecific binding molecules comprising a modified J chain, where the modified J chain comprises a J chain-associated antigen binding domain that specifically binds to an immune effector cell, e.g., a T cell, e.g., a CD4+ T cell or a CD8+ cytotoxic T cell or an NK cell.

[0150] In some embodiments, the modified J chain further comprises an immunostimulatory agent (ISA), such as a cytokine, such as interleukin-2 (IL-2) or interleukin-15 (IL-15), or a receptor-binding fragment or variant thereof, which in certain embodiments may be associated, either by bond or covalent attachment, to a portion of its receptor, such as the sushi domain of the IL-15 receptor-α. Such ISAs are described in detail in PCT Publication No. WO2021 / 030688, which is incorporated by reference herein in its entirety.

[0151] In certain embodiments, the J chain of an IgM antibody, an IgM-like antibody, an IgA antibody, an IgA-like antibody, an IgM-derived binding molecule, or an IgA-derived binding molecule provided herein is a variant J chain that includes one or more amino acid substitutions, e.g., amino acid substitutions that can alter the serum half-life of an IgM antibody, an IgM-like antibody, an IgA antibody, an IgA-like antibody, an IgM-derived binding molecule, or an IgA-derived binding molecule provided herein. For example, certain amino acid substitutions, deletions, or insertions can result in an IgM-derived binding molecule, upon administration to a subject animal, that exhibits an increased serum half-life compared to a reference IgM-derived binding molecule that is identical except for one or more single amino acid substitutions, deletions, or insertions in the variant J chain and that is administered to the same animal species using the same method. In certain embodiments, the variant J chain can include one, two, three, or four single amino acid substitutions, deletions, or insertions compared to the reference J chain.

[0152] In some embodiments, the multimeric binding molecule may comprise a variant J chain sequence, e.g., a variant sequence described herein that has reduced glycosylation or reduced binding to one or more multimeric Ig receptors (e.g., pIgR, Fc alpha-mu receptor (FcαμR), or Fc mu receptor (FcμR)). See, e.g., U.S. Pat. No. 10,899,835, which is incorporated by reference in its entirety. In certain embodiments, the variant J chain may comprise an amino acid substitution at an amino acid position corresponding to amino acid Y102 of mature wild-type human J chain (SEQ ID NO: 7). By "an amino acid corresponding to amino acid Y102 of mature wild-type human J chain" is meant an amino acid in the sequence of the J chain of any species that is homologous to Y102 in the human J chain. See U.S. Pat. No. 10,899,835. The position corresponding to Y102 in SEQ ID NO: 7 is conserved in the J chain amino acid sequences of at least 43 other species. See Figure 4 of U.S. Patent No. 9,951,134, which is incorporated herein by reference. Certain mutations at the position corresponding to Y102 in SEQ ID NO:7 can inhibit certain immunoglobulin receptors, such as human or mouse Fcαμ receptors, mouse Fcμ receptors, and / or human or mouse polymeric Ig receptors (pIg receptors), from binding to IgM pentamers containing mutant J chains. IgM antibodies, IgM-like antibodies, and IgM-derived binding molecules containing a mutation at the amino acid corresponding to Y102 in SEQ ID NO:7 have improved serum half-life when administered to an animal compared to the corresponding antibody, antibody-like molecule, or binding molecule that is identical except for the substitution and is administered in the same manner to the same species. In certain embodiments, the amino acid corresponding to Y102 in SEQ ID NO:7 can be substituted with any amino acid. In certain embodiments, the amino acid corresponding to Y102 in SEQ ID NO:7 can be substituted with alanine (A), serine (S), or arginine (R). In certain embodiments, the amino acid corresponding to Y102 in SEQ ID NO:7 may be substituted with alanine. In certain embodiments, the J chain, or functional fragment or variant thereof, is a variant human J chain and has the amino acid sequence of SEQ ID NO:8, i.e., as used herein, "J * It contains the J chain, also called "J chain."

[0153] A wild-type J chain typically contains one N-linked glycosylation site. In certain embodiments, a variant J chain or functional fragment thereof of a multimeric binding molecule provided herein contains an asparagine (N)-linked glycosylation motif N-X1-S / T, e.g., the mature human J chain (SEQ ID NO: 7) or J * (SEQ ID NO:8), wherein N is asparagine, X1 is any amino acid except proline, and S / T is serine or threonine, and the mutation prevents glycosylation at that motif. As demonstrated in U.S. Pat. No. 10,899,835, a mutation that prevents glycosylation at this site can result in a multimeric binding molecule provided herein that, upon administration to a subject animal, exhibits an increased serum half-life compared to a reference multimeric binding molecule that is identical except for one or more mutations that prevent glycosylation in the variant J chain and that is administered in the same manner to the same animal species.

[0154] For example, in certain embodiments, a variant J chain or functional fragment thereof of a binding molecule comprising a J chain provided herein may comprise an amino acid substitution at an amino acid position corresponding to amino acid N49 or amino acid S51 of SEQ ID NO:7 or SEQ ID NO:8, with the proviso that the amino acid corresponding to S51 is not substituted with threonine (T), or the variant J chain comprises an amino acid substitution at an amino acid position corresponding to both amino acids N49 and S51 of SEQ ID NO:7 or SEQ ID NO:8. In certain embodiments, the position corresponding to N49 of SEQ ID NO:7 or SEQ ID NO:8 is substituted with any amino acid, for example, alanine (A), glycine (G), threonine (T), serine (S), or aspartic acid (D). In certain embodiments, the position corresponding to N49 of SEQ ID NO:7 or SEQ ID NO:8 may be substituted with alanine (A). In another embodiment, the position corresponding to N49 of SEQ ID NO:7 or SEQ ID NO:8 may be substituted with aspartic acid (D). In some embodiments, the position corresponding to S51 of SEQ ID NO:7 or SEQ ID NO:8 is substituted with alanine (A) or glycine (G). In some embodiments, the position corresponding to S51 of SEQ ID NO:7 or SEQ ID NO:8 is substituted with alanine (A).

[0155] A multimeric bispecific or multispecific anti-CD38 binding molecule with a modified J chain that binds to immune effector cells. The present disclosure provides multimeric bispecific or multispecific binding molecules for use in the treatment of cancer (e.g., hematological cancers, e.g., multiple myeloma (MM)). In certain embodiments, the binding molecules are bispecific and target CD38 on cancer cells with high avidity while also targeting immune effector cells, e.g., CD4+ or CD8+ T cells or NK cells, with a single antigen-binding domain, thereby facilitating effector cell-mediated cancer cell killing while simultaneously minimizing excessive cytokine release. In certain embodiments, the multimeric bispecific anti-CD38 binding molecule is an anti-CD38 x anti-CD3 binding molecule.

[0156] Thus, the present disclosure provides a multimeric bispecific or multispecific binding molecule comprising two IgA or IgA-like bivalent binding units or five IgM or IgM-like bivalent binding units and one modified J chain, the modified J chain comprising at least a wild-type J chain or a functional fragment or variant thereof, and a J chain-associated antigen-binding domain that specifically binds to an immune effector cell. Each binding unit comprises an IgA, IgA-like, IgM or IgM-like heavy chain constant region or a multimerizing fragment thereof (as described elsewhere herein), and two antibody heavy chains each comprising at least a heavy chain variable region (VH) portion of the binding unit-associated antigen-binding domain. At least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, or all ten of the binding unit-associated antigen-binding domains specifically bind to CD38. The binding molecules provided herein can induce immune effector cell-dependent killing of cells expressing CD38, e.g., cancer cells.

[0157] In certain embodiments, the modified J chain of the binding molecules provided herein comprises a variant of a wild-type J chain or a fragment thereof, wherein the variant comprises one or more single amino acid substitutions, deletions or insertions that can affect the serum half-life of the binding molecule relative to the wild-type J chain, and the binding molecule, upon administration to an animal, exhibits an extended serum half-life relative to a reference binding molecule that is identical except for the one or more single amino acid substitutions, deletions or insertions in the J chain and that is administered in the same manner to the same animal species. For example, in certain embodiments, the J chain comprises a variant human J chain comprising the amino acid sequence of SEQ ID NO:8 ("J * ").

[0158] In certain embodiments, the J chain-associated antigen-binding domain of the provided binding molecules comprises an antibody or a fragment thereof. In certain embodiments, the antibody fragment is a single chain Fv (scFv). The scFv comprises a J chain or a fragment or variant, such as a J *The scFv may be fused to or chemically conjugated with the J chain. In certain embodiments, the scFv is fused to the J chain via a peptide linker, e.g., SEQ ID NOs: 9-13. As noted elsewhere in this disclosure, the scFv may be fused to the J chain, or a fragment or variant thereof, in any manner so long as the function of the J chain, i.e., its ability to assemble with IgM, IgM-like, IgA or IgA-like binding units to form dimers or pentamers, is not affected. For example, the scFv may be fused to the N-terminus of the J chain, or a fragment or variant thereof, the C-terminus of the J chain, or a fragment or variant thereof, or both the N-terminus and the C-terminus of the J chain, or a fragment or variant thereof.

[0159] The immune effector cell that the antigen-binding domain of the modified J chain binds to can be any immune effector cell that confers beneficial effects (e.g., mediates cell-based killing of CD38+ cancer cells) when it is associated with cancer cells targeted by CD38. In certain embodiments, the immune effector cell can be, but is not limited to, a T cell, such as a CD4+ T cell, a CD8+ T cell, a NKT cell or a γδ T cell, a B cell, a plasma cell, a macrophage, a dendritic cell, or a natural killer (NK) cell. In certain embodiments, the immune effector cell is a T cell, such as a CD4+ or CD8+ T cell. In certain embodiments, the immune effector cell is a CD8+ cytotoxic T cell. In certain embodiments, the immune effector cell is a NK cell.

[0160] When the immune effector cell is a T cell, e.g., a CD8+ T cell, the J chain associated antibody or fragment thereof, e.g., an scFv, can specifically bind to the T cell surface antigen CD3, e.g., CD3ε. In certain embodiments, the anti-CD3 scFv comprises an scFv heavy chain variable region (scFv VH) and an scFv light chain variable region (scFv VL), where the scFv VH comprises the scFv VH complementarity determining regions VHCDR1, VHCDR2, and VHCDR3, and the scFv VL comprises the scFv and VLCDR1, VLCDR2, VLCDR3, wherein VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3 comprise the amino acid sequences of SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:21, SEQ ID NO:22, and SEQ ID NO:23; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30, and SEQ ID NO:31; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30, and SEQ ID NO:33; SEQ ID NO:35, SEQ ID NO:36, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:41; SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:45; or SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:47, SEQ ID NO:39, SEQ ID NO:40, and SEQ ID NO:49. In some embodiments, VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2 and VLCDR3 comprise SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30 and SEQ ID NO:31, respectively. In some embodiments, scFv VH and scFv VL comprise an amino acid sequence that is at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO:16 and SEQ ID NO:20; SEQ ID NO:24 and SEQ ID NO:28; SEQ ID NO:24 and SEQ ID NO:32; SEQ ID NO:34 and SEQ ID NO:38; SEQ ID NO:42 and SEQ ID NO:44; or SEQ ID NO:46 and SEQ ID NO:48, respectively. In some embodiments, the scFv fragment comprises the scFv VH and scFv VL amino acid sequences of SEQ ID NO:24 and SEQ ID NO:28, respectively.

[0161] In certain other embodiments, the immune effector cell is a NK cell and the J chain associated antibody or fragment thereof, e.g., scFv, can specifically bind to CD16 or CD56. Many CD16 and CD56 scFvs are known, including those disclosed in U.S. Patent Nos. 9,035,026, 9,701,750, 10,730,941, 11,001,633, and McCall et al., 1999. Mol Immunol. 7:433-445.

[0162] The modified J chain of the multimeric bispecific anti-CD38 binding molecules provided herein, such as anti-CD38×anti-CD3 binding molecules, can be further modified to include additional heterologous moieties added to the J chain. Exemplary moieties are described, for example, in U.S. Pat. No. 9,951,134, U.S. Patent Application Publication No. US2019-0185570, U.S. Pat. No. 10,618,978, and PCT Publication No. WO2021 / 030688, all of which are incorporated herein by reference in their entirety. In certain embodiments, the modified J chain of the multimeric bispecific anti-CD38 binding molecules provided herein, such as anti-CD38×anti-CD3 binding molecules, can further include an immune stimulatory agent ("ISA") fused or chemically conjugated to the J chain or a fragment or variant thereof. For example, the ISA can include a cytokine or a receptor-binding fragment or variant thereof. In certain embodiments, the J chain-associated ISA comprises (a) an interleukin-15 (IL-15) protein or a receptor-binding fragment or variant thereof ("I"), and (b) an interleukin-15 receptor-alpha (IL-15Rα) fragment ("R") that includes a sushi domain or a variant thereof that can associate with I, wherein the J chain or a fragment or variant thereof and at least one of I and R, or both I and R, are associated as a fusion protein, and the I and R can associate to function as an ISA. In certain embodiments, the ISA may be fused to the J chain via a peptide linker.

[0163] Polynucleotides, Vectors and Host Cells The present disclosure further provides polynucleotides, e.g., isolated polynucleotides, recombinant polynucleotides, and / or non-naturally occurring polynucleotides, comprising a nucleic acid sequence that encodes an antigen-binding domain provided herein or that encodes a polypeptide subunit of an antibody or antibody-like molecule provided herein (e.g., a dimeric, hexameric, or pentameric antibody or antibody-like molecule). By "polypeptide subunit" is meant a portion, binding unit, or antigen-binding domain of an antibody or antibody-like molecule that can be translated independently. Examples include, but are not limited to, an antibody variable domain (e.g., VH or VL), a J chain (including modified J chains provided herein), a secretory component, a single chain Fv, an antibody heavy chain, an antibody light chain, an antibody heavy chain constant region, an antibody light chain constant region, and / or any fragment, variant, or derivative thereof.

[0164] In certain embodiments, the polynucleotide comprises a nucleic acid sequence encoding a polypeptide subunit of the binding molecule described herein. In some embodiments, the polynucleotide encodes a polypeptide subunit comprising a heavy chain constant region of the binding molecule and at least an antibody VH portion of the binding domain. In some embodiments, the polynucleotide encodes a polypeptide subunit comprising a heavy chain of the binding molecule. In some embodiments, the polynucleotide encodes a polypeptide subunit comprising a VH comprising HCDR1, HCDR2 and HCDR3 regions, wherein HCDR1, HCDR2 and HCDR3 respectively comprise the amino acid sequences of SEQ ID NO:65, SEQ ID NO:66 and SEQ ID NO:67; SEQ ID NO:57, SEQ ID NO:58 and SEQ ID NO:59; SEQ ID NO:73, SEQ ID NO:74 and SEQ ID NO:75; SEQ ID NO:81, SEQ ID NO:82 and SEQ ID NO:83; SEQ ID NO:89, SEQ ID NO:90 and SEQ ID NO:91; SEQ ID NO:97, SEQ ID NO:98 and SEQ ID NO:99; SEQ ID NO:105, SEQ ID NO:106 and SEQ ID NO:107; SEQ ID NO:113, SEQ ID NO:114 and SEQ ID NO:115; SEQ ID NO:121, SEQ ID NO:122 and SEQ ID NO:123; SEQ ID NO:65, SEQ ID NO:134 and SEQ ID NO:67; SEQ ID NO:65, SEQ ID NO:182 and SEQ ID NO:67; or SEQ ID NO:65, SEQ ID NO:135 and SEQ ID NO:67.

[0165] In some embodiments, the polynucleotide encodes a polypeptide subunit that comprises a light chain constant region of the binding molecule and at least an antibody VL portion of the binding domain. In some embodiments, the polynucleotide encodes a polypeptide subunit that comprises a light chain of the binding molecule. In some embodiments, the polynucleotide encodes a polypeptide subunit comprising a VL comprising LCDR1, LCDR2 and LCDR3 regions, wherein LCDR1, LCDR2 and LCDR3 respectively comprise the amino acid sequences of SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:109, SEQ ID NO:110 and SEQ ID NO:111; SEQ ID NO:117, SEQ ID NO:118 and SEQ ID NO:119; SEQ ID NO:125, SEQ ID NO:126 and SEQ ID NO:127; SEQ ID NO:143, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:144, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:145, SEQ ID NO:94 and SEQ ID NO:95; or SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95.

[0166] In certain embodiments, a polypeptide subunit may comprise an IgM or IgM-like heavy chain constant region, or a multimerizing fragment thereof, associated with, e.g., fused to, an antigen binding domain or a subunit thereof (e.g., the VH portion of the antigen binding domain, or the VL portion of the antigen binding domain), all of which are provided herein. In certain embodiments, a polynucleotide may encode a polypeptide subunit comprising a human IgM heavy chain constant region, a human IgM-like heavy chain constant region, a human IgA heavy chain constant region, a human IgA-like heavy chain constant region, or a multimerizing fragment thereof (e.g., SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, or SEQ ID NO:4), any of which is associated with, e.g., fused to, an antigen binding domain or a subunit thereof (e.g., the C-terminus of the VH).

[0167] To form an antigen-binding domain or variable region of an antibody that specifically binds to CD38, the provided polynucleotides can be inserted into an expression vector template, for example, for a monomeric antibody (e.g., an IgG antibody) or for an IgG and / or IgA construct, thereby generating a monomeric antibody containing a single binding unit, or a multimeric antibody or multimerizing antibody-like molecule having at least two bivalent binding units. Briefly, nucleic acid sequences encoding heavy and light chain variable domain sequences can be synthesized or amplified from an existing molecule and inserted into a vector in the appropriate orientation and in frame such that upon expression, the vector will generate a full-length heavy or light chain. Vectors useful for these purposes are known in the art. Such vectors can also include enhancers and other sequences required to achieve expression of the desired chain. Multiple vectors or a single vector can be used. These vectors are transfected into a host cell, after which the chains are expressed and purified. Upon expression, the chains form a fully functional multimeric binding molecule, as reported in the literature. The fully assembled multimeric binding molecule can then be purified by standard methods. The expression and purification process can be carried out on a commercial scale, if desired.

[0168] The present disclosure further provides a composition comprising two or more polynucleotides, which may collectively encode the antigen binding domain or antibody or antibody-like molecule described herein, such as a monomeric, dimeric, hexameric or pentameric antibody. In certain embodiments, the composition may comprise a polynucleotide encoding the above-mentioned IgG, IgM and / or IgA heavy chain, or a fragment thereof, such as a human IgG, IgM or IgA heavy chain, wherein the IgG, IgM and / or IgA heavy chain comprises at least the provided VH of the CD38 antigen binding domain provided herein, and a polynucleotide encoding a light chain or a fragment thereof, such as a human kappa or lambda light chain, comprising at least the provided VL of the CD38 antigen binding domain provided herein. The provided polynucleotide composition may further comprise a polynucleotide encoding a J chain, such as a human J chain, or a fragment, variant or derivative thereof. In certain embodiments, the polynucleotides constituting the compositions provided herein may be located on two, three or more separate vectors (e.g., expression vectors). Such vectors are provided by the present disclosure.In certain embodiments, two or more of the polynucleotides that constitute the compositions provided herein can be located on a single vector, such as an expression vector.Such vectors are provided by the present disclosure.

[0169] In certain embodiments, the present disclosure provides a composition comprising two, three or more polynucleotides provided herein, which together can encode an anti-CD38 binding molecule provided herein, such as a multimeric bispecific anti-CD38 binding molecule, such as an anti-CD38 x anti-CD3 binding molecule. In certain embodiments, the polynucleotides can be located on separate vectors. In certain embodiments, two or more polynucleotides can be located on the same vector. Such vectors are similarly provided by the present disclosure.

[0170] The disclosure further provides a host cell, e.g., a prokaryotic or eukaryotic host cell, that comprises a polynucleotide or two or more polynucleotides encoding an anti-CD38 binding molecule provided herein, e.g., a multimeric bispecific anti-CD38 binding molecule, e.g., an anti-CD38 x anti-CD3 binding molecule, or any subunit thereof, or comprises a polynucleotide composition provided herein, or comprises a vector or two, three or more vectors that collectively encode the binding molecules provided herein, or any subunits thereof.

[0171] In a related embodiment, the present disclosure provides a method of producing a multimeric binding molecule provided by the present disclosure, the method comprising culturing a host cell provided herein and recovering the multimeric binding molecule.

[0172] How to use The present disclosure further provides a method of treating a disease or disorder, e.g., cancer or other malignancy, e.g., hematological cancer or hematological malignancy, in a subject in need of such treatment, comprising administering to the subject a therapeutically effective amount of an anti-CD38 antibody or antigen-binding fragment or derivative thereof provided herein, e.g., an anti-CD38xanti-CD3 antibody. By "therapeutically effective dose or amount" or "effective amount" is intended the amount of binding molecule that, when administered, results in a desired response, e.g., killing of tumor cells in a subject.

[0173] In certain embodiments, the cancer to be treated can be any cancer in which malignant cells express or overexpress CD38.For example, the cancer can be blood cancer, such as chronic lymphocytic leukemia (CLL), multiple myeloma (MM), Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphoma (PTCL), and various solid tumors, such as prostate cancer, non-small cell lung cancer (NSCLC), squamous cell carcinoma of the head and neck (SCCHN), ovarian cancer, and liver cancer.In some embodiments, the cancer is blood cancer.In some embodiments, the cancer is MM.

[0174] The effective dose of the composition for the treatment of cancer will vary depending on many different factors, such as the means of administration, the target site, the physiological condition of the subject, whether the subject is a human or an animal, and other medicinal agents administered. Typically, the subject is a human, although non-human mammals, including transgenic mammals, can also be treated.

[0175] The subject to be treated can be any mammal in need of treatment, and in certain embodiments, the subject is a human subject.

[0176] The preparation administered to a subject, in its simplest form, is an anti-CD38 antibody or antigen-binding fragment or derivative thereof provided herein, e.g., an anti-CD38 x anti-CD3 antibody, administered in a conventional dosage form, which may be combined with a pharmaceutical excipient, carrier, or diluent as described elsewhere herein.

[0177] Compositions of the present disclosure may be administered by any suitable method, for example, parenterally, intraventricularly, orally, by inhalation spray, topically, rectally, nasally, buccally, vaginally, or via an implanted reservoir. The term "parenteral" as used herein includes subcutaneous, intravenous, intramuscular, intra-articular, intrasynovial, intrasternal, intrathecal, intrahepatic, intralesional and intracranial injection or infusion techniques.

[0178] Pharmaceutical Compositions and Methods of Administration The components of the composition comprising the anti-CD38 antibody or antigen-binding fragment or derivative thereof provided herein, e.g., anti-CD38 x anti-CD3 antibody, may vary depending on the route of administration. Exemplary routes of administration include intratumoral, oral, parenteral, by inhalation, or topical routes. The term parenteral as used herein includes, for example, intravenous, intraarterial, intraperitoneal, intramuscular, subcutaneous, rectal, or vaginal administration. Although these forms of administration are contemplated as suitable forms, another example of a form for administration would be an injectable solution for intratumoral, intravenous, or intraarterial injection or infusion. Suitable pharmaceutical compositions may include buffers (e.g., acetate, phosphate, or citrate buffers), surfactants (e.g., polysorbates), and optionally stabilizers (e.g., human albumin), etc.

[0179] As discussed herein, the anti-CD38 antibodies or antibody-like molecules provided herein, such as multimeric anti-CD38 x anti-CD3 antibodies, can be administered in a pharmacologic effective amount to administer treatment to a subject in need thereof. In this regard, it will be understood that the disclosed antibodies, or antigen-binding fragments or derivatives thereof, can be formulated to facilitate administration and promote stability of the active agent. Thus, the pharmaceutical composition can include a pharmacologic acceptable non-toxic sterile carrier, such as saline, non-toxic buffers, preservatives, and the like. A pharmacologic effective amount of the antibodies, or antigen-binding fragments or derivatives thereof, provided herein means an amount sufficient to achieve effective binding to the target and provide a therapeutic benefit. Suitable formulations are described in Remington's Pharmaceutical Sciences, e.g., 21st Edition (Lippincott Williams & Wilkins) (2005).

[0180] Certain pharmaceutical compositions provided herein may be administered orally in acceptable dosage forms, including, for example, capsules, tablets, aqueous suspensions or solutions. Certain pharmaceutical compositions may also be administered by nasal aerosol or inhalation. Such compositions may be prepared as a solution in saline using benzyl alcohol or other suitable preservatives, absorption enhancers that improve bioavailability, and / or other conventional solubilizing or dispersing agents.

[0181] The amount of anti-CD38 antibody or antibody-like molecule disclosed herein, e.g., multimeric anti-CD38 x anti-CD3 antibody, that can be combined with a carrier material to produce a single dosage form will vary depending, for example, on the subject being treated and the particular mode of administration. The composition can be administered as a single dose, multiple doses, or over an established infusion period. Dosage regimens can also be adjusted to provide the optimum desired response (e.g., therapeutic response).

[0182] In accordance with the scope of the present disclosure, the anti-CD38 antibodies or antibody-like molecules provided herein, such as multimeric anti-CD38xanti-CD3 antibodies, can be administered to a subject in need of therapy in an amount sufficient to produce a therapeutic effect. The anti-CD38 antibodies or antibody-like molecules provided herein, such as anti-CD38xanti-CD3 antibodies, can be administered to a subject in conventional dosage forms prepared by combining the antibodies or antibody-like molecules of the present disclosure with conventional pharma- ceutically acceptable carriers or diluents according to known techniques. The form and nature of the pharma-ceutically acceptable carrier or diluent can be determined by the amount of active ingredient to be combined therewith, the route of administration, and other well-known variables.

[0183] The present disclosure also provides the use of an anti-CD38 antibody or antibody-like molecule provided herein, such as a multimeric anti-CD38x anti-CD3 antibody, in the manufacture of a medicament for treating cancer or other malignancies. The present disclosure also provides an anti-CD38 antibody or antibody-like molecule provided herein, such as an anti-CD38x anti-CD3 antibody, for use in treating cancer.

[0184] The present disclosure employs, unless otherwise indicated, conventional techniques of cell biology, cell culture, molecular biology, transgenic biology, microbiology, recombinant DNA, and immunology, which are within the skill of those in the art and are fully explained in the literature. For example, Green and Sambrook, ed. (2012) Molecular Cloning A Laboratory Manual (4th ed.; Cold Spring Harbor Laboratory Press), Sambrook et al., ed. (1992) Molecular Cloning: A Laboratory Manual, (Cold Springs Harbor Laboratory, NY), DNGlover and BD Hames, eds., (1995) DNA Cloning 2d Edition (IRL Press), Volumes 1-4, Gait, ed. (1990) Oligonucleotide Synthesis (IRL Press), Mullis et al. U.S. Patent No. 4,683,195, Hames and Higgins, eds. Press), Freshney(2016)Culture Of Animal Cells,7th Edition (Wiley-Blackwell), Woodward, J., Immobilized Cells And Enzymes (IRL Press) (1985), Perbal (1988) A Practical Guide To Molecular Cloning;2d Edition (Wiley-Interscience), Miller and Calos eds. (1987) Gene Transfer Vectors For Mammalian Cells, (Cold Spring Harbor Laboratory), SCSee Makrides (2003) Gene Transfer and Expression in Mammalian Cells (Elsevier Science), Methods in Enzymology, Vols. 151-155 (Academic Press, Inc., N.Y.), Mayer and Walker, eds. (1987) Immunochemical Methods in Cell and Molecular Biology (Academic Press, London), Weir and Blackwell, eds., and Ausubel et al. (1995) Current Protocols in Molecular Biology (John Wiley and Sons).

[0185] General principles of antibody engineering are described, for example, in Strohl, WR, and LM Strohl (2012), Therapeutic Antibody Engineering (Woodhead Publishing). General principles of protein engineering are described, for example, in Park and Cochran, eds. (2009), Protein Engineering and Design (CDC Press). General principles of immunology are described, for example, in Abbas and Lichtman (2017) Cellular and Molecular Immunology 9th Edition (Elsevier). In addition, standard methods in immunology known in the art may be followed, for example, Current Protocols in Immunology (Wiley Online Library), Wild, D. (2013), The Immunoassay Handbook 4th Edition (Elsevier Science), Greenfield, ed. (2013), Antibodies, a Laboratory Manual, 2d Edition (Cold Spring Harbor Press), and Ossipow and Fischer, eds., (2014), Monoclonal Antibodies: Methods and Protocols (Humana Press).

[0186] All of the references cited above, and all references cited herein, are hereby incorporated by reference in their entirety.

[0187] The following examples are offered by way of illustration and not by way of limitation. EXAMPLES

[0188] Example 1: Generation of CD38-binding agents An antibody discovery campaign to generate CD38-binding antibodies was conducted using a commercial supplier (Antibody Solutions). Three mouse strains, Balb / C, NZB / W, and CD1, were immunized with human and cynomolgus (cyno) CD38 extracellular domain proteins provided by ACROBiosystems. For immunization, two different adjuvants were used: alhydrogel / muramyl dipeptide (ALD / MDP) and Sigma Adjuvant System® / RIBI (SAS / RIBI). A total of six hybridoma libraries were generated. Hybridoma supernatants were screened to identify binding of anti-CD38 antibodies to recombinant human CD38 and recombinant cynomolgus CD38 using enzyme-linked immunosorbent assay (ELISA). In addition, supernatants were screened to identify anti-CD38 antibodies that bind to cells expressing human CD38. 48 clones that bind to both human and cynomolgus CD38 were expanded and sequenced. After sequencing, nine clones were identified that contained unique sets of CDR sequences. The sequences of the anti-CD38 mouse hybridoma clones are shown in Table 2.

[0189] Table 2: Hybridoma clone sequences TIFF2025506341000004.tif104170TIFF2025506341000005.tif242170TIFF2025506341000006.tif161170

[0190] Example 2: Generation of chimeric CD38-binding agents Chimeric IgM and IgG constructs were generated from the anti-CD38 mouse hybridoma clones of Example 1 using standard cloning protocols. Briefly, for the IgM constructs, the heavy and light chain variable regions (VH and VL) of eight anti-CD38 mouse hybridoma clones were cloned into an IgM format containing a modified J chain with a CD3-binding single chain variable fragment (scFv). The IgM antibodies are listed in Table 3. The resulting constructs were expressed in Expi293 cells and purified according to the method described in Keyt et al., Antibodies: 9:53, doi:10.3390 / antib9040053 (2020). Chimeric IgM antibodies were successfully expressed and assembled as pentamers with J chains for clones A, B, C, E, F and H.

[0191] Table 3. Chimeric CD38 x CD3 IgM antibody TIFF2025506341000007.tif36145

[0192] Chimeric human IgG1 CD38 binders were generated by cloning the entire mouse VH and VL regions of the clones of Example 1 into a human IgG1 format following standard cloning protocols. Human IgG constructs were synthesized, expressed and purified by a commercial supplier. A subset of the chimeric IgG antibodies used in the following examples are listed in Table 4.

[0193] Table 4 Chimeric IgG antibodies TIFF2025506341000008.tif16128

[0194] Example 3: Binding specificity of chimeric CD38xCD3 IgM antibodies The binding specificity of the chimeric CD38×CD3 IgM antibodies generated in Example 2 for human and cynomolgus monkey (cyno) CD38 was measured in an ELISA assay as follows: 96-well white polystyrene ELISA plates (Pierce 15042) were coated with recombinant human or cynomolgus monkey CD38 extracellular domain protein provided by ACROBiosystems and incubated overnight at 4° C. The plates were then washed five times with 0.05% phosphate-buffered saline (PBS)-polysorbate sold under the trade name TWEEN® (PBS-TWEEN®) and blocked with 2% bovine serum albumin (BSA)-PBS. After blocking, 100 μL of serial dilutions of chimeric CD38×CD3 IgM antibodies, standards and controls were added to each well of the plate and incubated for 2 hours at room temperature. Plates were then washed 10 times with 0.05% PBS-TWEEN® and incubated with horseradish peroxidase (HRP)-conjugated mouse anti-human kappa secondary antibody (SouthernBiotech, clone SB81a) for 30 minutes. After 10 final washes with 0.05% PBS-TWEEN®, plates were read using SUPERSIGNAL™ chemiluminescent substrate (ThermoFisher, 37070). Luminescence data was collected on an ENVISION® plate reader (PERKINELMER®) and analyzed with GRAPHPAD PRISM® using a four-parameter logistic model.

[0195] Figures 1A-1B show the binding of chimeric CD38xCD3 IgM antibodies to human CD38 (Figure 1A) and cynomolgus monkey CD38 (Figure 1B). Data are expressed as relative light units (RLU) for the binding of chimeric CD38xCD3 IgM antibodies (IgM A-1, IgM B-1, IgM C-1, IgM E-1, IgM F-1, and IgM H-1).

[0196] All chimeric CD38xCD3 IgM antibodies bound to human and cynomolgus CD38 with similar affinity in a dose-responsive manner.

[0197] In addition, binding to cell surface human CD38 was evaluated using the myeloma cell line NCI-H929 (H929) and flow cytometry analysis. Briefly, H929 cells were stained with serial dilutions of chimeric CD38xCD3 IgM antibody for 30 minutes at 4°C. Cells were washed twice and stained with ALEXA FLUOR® 488 (AF488)-conjugated mouse anti-human kappa secondary antibody (SouthernBiotech, clone SB81a) for 30 minutes at 4°C. Cells were then washed twice and resuspended in fluorescence-activated cell sorting (FACS) staining buffer and measured using flow cytometry.

[0198] Figure 2 shows the binding of chimeric CD38xCD3 IgM antibodies to NCI-H929 cells as measured by flow cytometry. Data are presented as median fluorescence intensity (FL-1 parameter for the detection of AF488) for the chimeric CD38xCD3 IgM antibodies (IgM A-1, IgM B-1, IgM C-1, IgM E-1, IgM F-1, and IgM H-1).

[0199] In the binding assay, the chimeric CD38xCD3 IgM antibodies IgM B-1, IgM E-1, and IgM H-1 had particularly good activity.

[0200] Example 4: Testing of chimeric CD38xCD3 IgM antibodies in functional assays The T-cell dependent cytotoxicity (TDCC) activity of chimeric CD38xCD3 IgM antibodies was tested in an in vitro co-culture assay. Briefly, peripheral blood mononuclear cells (PBMCs) or CD3+ pan T cells were co-cultured with luciferase-tagged H929 and OPM2 myeloma cell lines at different effector-to-target ratios (1:1, 5:1, and 20:1). Cell cytotoxicity was read at 24, 48, 72, and / or 96 hours using a luciferase assay substrate provided by PROMEGA® and converted to the maximum percentage of cells killed (% max kill). Representative data are shown as the measured EC50 The values ​​are shown in Tables 5 to 8 below.

[0201] Table 5. Functional properties of chimeric CD38xCD3 IgM antibodies on co-cultures (1:1) of CD3+ T cells with luciferase-tagged H929 cells TIFF2025506341000009.tif41164

[0202] Table 6. Functional properties of chimeric CD38xCD3 IgM antibodies on PBMC cocultures with luciferase-tagged H929 cells (1:1) TIFF2025506341000010.tif41153

[0203] Table 7. Functional properties of chimeric CD38xCD3 IgM antibodies on co-cultures of CD3+ T cells with luciferase-tagged OPM2 cells (1:1) TIFF2025506341000011.tif81153

[0204] Table 8. Functional properties of chimeric CD38xCD3 IgM antibodies on co-cultures (1:1) of PBMCs with luciferase-tagged OPM2 cells TIFF2025506341000012.tif81152

[0205] In the TDCC assay, the chimeric CD38xCD3 IgM antibodies IgM B-1 and IgM E-1 had particularly good activity.

[0206] Example 5: Humanization of CD38 antibody Clones B and E were selected for humanization based on the activity of the corresponding chimeric CD38xCD3 IgM antibodies in binding and TDCC assays. In addition, known anti-CD38 antibodies OKT10 (VH-SEQ ID NO: 162, VL-SEQ ID NO: 163) and HB7 (VH-SEQ ID NO: 164, VL-SEQ ID NO: 165) were humanized. Human antibodies provided by the RCSB Protein Data Bank (available on the World Wide Web at rcsb.org) were selected as framework acceptors: 4KQ3 for clone B; 5I15 for clone E; 3MOD, 5FUZ or 5K59 for OKT10; and 5HYS, 5SX4 or 4R7D for HB7. Complementarity determining regions (CDRs) of mouse hybridoma clones were directly grafted onto the human framework acceptors. Some sequences were further designed to remove potential deamidation sites or other modifications. The resulting sequences are shown in Table 9 for the clones and in Table 10 for OKT10 and HB7. The humanized VH and VL sequences were then cloned into human IgG and IgM formats following standard cloning protocols. A subset was used for further experiments and is listed in Table 11.

[0207] Table 9. Humanized sequences of hybridoma clones TIFF2025506341000013.tif229170TIFF2025506341000014.tif103170

[0208] Table 10. Other humanized CD38-binding agents TIFF2025506341000015.tif122170TIFF2025506341000016.tif195170

[0209] Table 11. IgM and IgG antibodies TIFF2025506341000017.tif81149

[0210] Example 6: Affinity measurement of humanized IgG antibody by biolayer interferometry The binding affinity of the chimeric IgG and humanized IgG variants described in Example 5 to recombinant human CD38 protein (ACROBiosystems, Cat#CD8-H5224) was determined by biolayer interferometry (BLI) on an OCTET® 384 system (Sartorius / Forte Biosciences) using an anti-human IgG FC biosensor (Sartorius, Part#18-5004) and standard protocol. Samples and buffer were applied to a 384-well plate. After an initial baseline calibration for 60 seconds, the sensor was loaded with 20 nM of IgG antibody. The biosensor was immersed in buffer to reach a baseline value and incubated with 2-fold serially diluted human CD38 protein starting at 100 nM for association for 600 seconds, followed by incubation in buffer for 900 seconds for dissociation. The affinity was analyzed by ForteBio Data Analysis Software 9.0 using a 1:1 global fit model, and the resulting binding characteristics are shown in Table 12 below.

[0211] Table 12. Binding affinity of chimeric IgG and humanized IgG variants to recombinant human CD38 protein TIFF2025506341000018.tif38128

[0212] The humanized IgG variants have comparable binding properties compared to their chimeric IgG counterparts.

[0213] Example 7: Humanized CD38xCD3 IgM with various CD3 binding domains Bispecific IgMs with different CD38 and CD3 binding domains were tested in T cell redirected cytotoxicity assays using CD3+ pan T cells and luciferase (Luc) tagged H929 or OPM2 myeloma cell lines at effector to target ratios of 10:1 or 1:1. Cell cytotoxicity was assessed at 48 hours (H929 cells) or 72 hours (OPM2 cells) as described in Example 4 using luciferase assay substrate provided by PROMEGA®. Results are shown in Table 13 (H929 cells) and Table 14 (OPM2 cells).

[0214] Table 13. Cytotoxicity of humanized CD38xCD3 IgM against H929 cells TIFF2025506341000019.tif51155

[0215] Table 14. Cytotoxicity of humanized CD38xCD3 IgM against OPM2 cells TIFF2025506341000020.tif51153

[0216] These data suggest that humanized CD38×CD3 IgM antibodies have similar EC 50 These results demonstrate that near complete killing of H929 and OPM2 cells was achieved.

[0217] Example 8: Specificity of humanized CD38xCD3 IgM antibodies The specificity of the humanized CD38xCD3 IgM antibodies was measured by ELISA assay as follows: 96-well white polystyrene ELISA plates (PIERCE™, 15042) were coated overnight at 4°C with 100 μL per well of 1 μg / mL recombinant human CD38 (ACROBiosystems, CD8-H5224), mouse CD38 (ACROBiosystems, CD8-M5223), porcine CD38 (BPS Bioscience, 101019), canine CD38 (BPS Bioscience, Cat. No. 100955), rabbit CD38 (SinoBiological, 65003-T08H), or human CD157 protein (SinoBiological, 10060-H08H). Plates were then washed with 0.05% PBS-polysorbate sold under the trade name TWEEN® (PBS-TWEEN®) and blocked with 2% BSA-PBS. After blocking, 100 μL of serial dilutions of humanized CD38×CD3 IgM antibody and controls were added to the wells and incubated for 2 hours at room temperature. Plates were then washed and incubated with HRP-conjugated mouse anti-human kappa antibody (SouthernBiotech, 9230-05, diluted 1:6000 in 2% BSA-PBS) for 30 minutes. After a final wash, plates were read using SUPERSIGNAL™ chemiluminescent substrate (ThermoFisher, 37070). Luminescence data was collected on an ENVISION® plate reader (PERKINELMER®) and analyzed in GRAPHPAD PRISM® using a 4-parameter logistic model.

[0218] Figure 3 shows the binding of humanized CD38xCD3 IgM antibodies to human CD38 at different antibody concentrations as measured by ELISA. Data are expressed in relative light units (RLU) for humanized CD38xCD3 IgM antibodies (IgM B-2, IgM B-4, IgM E-2, IgM E-4, IgM OKT10-2, and IgM OKT10-4). These antibodies did not bind to mouse CD38 or human CD157.

[0219] In addition, a subset of CD38xCD3 IgM antibodies (IgM B-2, IgM E-2, and IgM OKT10-2) was evaluated for binding to human CD38, porcine CD38, canine CD38, or rabbit CD38. Binding was comparable to that seen in Figure 3 for human CD38, but nearly no binding was detected for porcine CD38, canine CD38, or rabbit CD38 (data not shown).

[0220] Example 9: Pharmacokinetics of CD38xCD3 IgM antibodies Pharmacokinetic parameters of various CD38xCD3 IgM antibodies were measured in an in vivo mouse model as follows: Balb / c mice were injected with 5 mg / kg IgM B-2, IgM E-2, and IgM OKT10-2 by intravenous infusion. Blood samples were collected in two mice per time point for a total of 10 or 12 time points per antibody. Each mouse was bled once via the facial vein (100 μL) and then once more via terminal cardiac puncture (maximum obtainable volume, approximately 500 μL). Serum concentrations of each antibody in the blood were measured at each time point using standard ELISA assays. Quality metrics were validated for all ELISAs and t 1 / 2 PK parameters, including clearance (CL), area under the curve (AUC) and maximum concentration (Cmax), were derived using standard curve fitting techniques (Win Non Lin, Phoenix Software). A plot of concentration over time is shown in Figure 4. PK parameters are presented in Table 15.

[0221] Table 15. PK parameters TIFF2025506341000021.tif26148

[0222] Example 10: CD38xCD3 IgM exhibits similar TDCC titers and less cytokine release compared to CD38xCD3 IgG The T-cell dependent cytotoxicity (TDCC) activity of the humanized CD38xCD3 IgM antibody, IgM B-2, was tested in an in vitro co-culture assay as described in Example 4. For comparison, three IgG-based molecules were generated and tested in an assay that also detects antibody-dependent cytotoxicity (i.e., the primary mechanism of CD38 IgG Y and CD38 IgG Z), CD38xCD3 IgG Y, CD38 IgG Z ...

[0223] Supernatants from the assays were collected at various time points and TNF-α and IFN-γ levels were measured in the supernatants using the BD Cytometric Bead Assay Human Th1 / Th2 Cytokine Kit II (BD 551809) according to the manufacturer's protocol, and results were then analyzed in GraphPad Prism.

[0224] The cytotoxicity curves obtained for CD38 IgG Y, CD38 IgG Z, CD38xCD3 IgG, and IgM B-2 are shown in Figure 5A-C and show the maximum percentage killing, TNF-α and TNF-γ, and killing EC 50Values ​​are shown in Table 16. Figure 5A shows dose response curves for killing of H929 cells (% kill) by increasing concentrations of CD38 IgG Y, CD38 IgG Z, CD38xCD3 IgG, and IgM B-2. Figure 5B shows the resulting TNF-α levels after treatment with increasing concentrations of CD38 IgG Y, CD38 IgG Z, CD38xCD3 IgG, and IgM B-2. Figure 5C shows the resulting IFN-γ levels after treatment with increasing concentrations of CD38 IgG Y, CD38 IgG Z, CD38xCD3 IgG, and IgM B-2.

[0225] These data indicate that CD38xCD3 IgG and IgM B-2 had similar levels of H929 cell killing, but IgM B-2 resulted in less cytokine release compared to CD38xCD3 IgG.

[0226] Table 16. Functional properties of CD38xCD3 IgM on co-cultures of PBMCs with luciferase-tagged H929 cells TIFF2025506341000022.tif36152

[0227] Example 11: CD38xCD3 IgM induces stronger CD8+ T cell proliferation and reduces strongly immunosuppressive CD38hi regulatory T cells The effect of CD38xCD3 IgM, IgM B-2, on the proliferation of CD8+ T cells and CD38hi regulatory T cells was investigated as described in Example 4. In addition to using co-cultures of H929 and PBMC from three different donors, incubation was extended to 7 days and treatment with 5 nM CD38xCD3 IgG, or IgM B-2.

[0228] Figure 6A shows the CD8+ T cell counts for each PBMC donor after treatment with CD38xCD3 IgG, or IgM B-2. Figure 6B shows the ratio of CD8+ T cell counts to regulatory T cell counts (Treg) for each PBMC donor after treatment with CD38xCD3 IgG, or IgM B-2. Figure 6C shows the CD38hi regulatory T cell counts for each PBMC donor after treatment with CD38xCD3 IgG, or IgM B-2.

[0229] These data indicate that IgM B-2 induced greater CD8+ T cell proliferation than CD38×CD3 IgG and reduced the number of highly immunosuppressive CD38hi regulatory T cells to a greater extent than CD38×CD3 IgG.

[0230] Example 12: CD38 x CD3 IgM inhibits in vitro human multiple myeloma colony formation To investigate the effect of IgM B-2, a CD38 × CD3 IgM, on multiple myeloma in vitro, a colony formation assay was used. Frozen bone marrow mononuclear cells from four separate multiple myeloma (MM) donors and two normal bone marrow donors were thawed and plated at 0.5 × 10 in liquid medium containing 10% PHA-conditioned medium (MM bone marrow) or cytokines (normal bone marrow). 6 Cells were resuspended at 1000 cells / mL and seeded into wells of a 24-well plate containing the test antibody or solvent control. Cells were incubated in liquid culture for 120 hours. After incubation, cells in each well were carefully dispersed by pipetting. 400 microliters of cells (and medium) were removed from each well and added to 4.0 mL of methylcellulose containing 10% PHA-conditioned medium (MM patients) or cytokines (normal donors). The tube of methylcellulose was vortexed to ensure that the cells were evenly distributed throughout the matrix. Cultures were prepared in 35 mm dishes with three replicates per condition. Replicate dishes were placed at 37°C and 5% CO2 for a total of 14-16 days, after which the resulting colonies were evaluated and counted based on morphology.

[0231] FIG. 7A shows in vitro colony formation of multiple myeloma cells from four different donors following treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2.

[0232] Figure 7B shows in vitro colony formation of erythroid cells from two different normal bone marrow donors following treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2. Total erythroid cells at the CFU-E (late erythroid progenitor) and BFU-E (early erythroid progenitor) developmental stages were measured.

[0233] FIG. 7C shows in vitro colony formation of granulocyte-macrophage progenitor cells (CFU-GM) from two different normal bone marrow donors following treatment with vehicle control, 10 nM IgM B-2, or 50 nM IgM B-2.

[0234] These data indicate that IgM B-2 inhibited multiple myeloma colony formation but not normal erythroid or granulocyte / macrophage colony formation.

[0235] Example 12: CD38xCD3 IgM exhibits reduced friendly combat in vitro compared to CD38xCD3 IgG Generating cancer immunotherapies continues to be a challenge because targetable antigens, such as CD38, are shared by T cells and tumor cells. This common antigen expression can cause T cells to undergo self-killing or "friend-fight", potentially reducing the effectiveness of immunotherapy against tumor cells. To investigate the effects of friend-fighting by treatment with IgM B-2, a CD38×CD3 IgM, the following experiment was performed.

[0236] Activated / expanded CD3+ pan T cells with higher CD38 expression levels were used to investigate the possibility of T cell-fighting in vitro. Naive T cells were activated and expanded using a T cell activation / expansion kit provided by Miltenyi Biotec (cat. no. 130-091-441). Activated T cells were then treated in vitro with 5 nM CD38 x CD3 IgG, or IgM B-2. T cell-fighting was assessed at 72 hours by flow cytometry analysis to quantify viable CD4+ and CD8+ T cells. The number of viable cells per well was then normalized to untreated control wells.

[0237] FIG. 8 shows that IgM B-2 exhibits less T cell-cell killing compared to CD38×CD3 IgG for both CD4+ and CD8+ T cells.

[0238] Example 13: CD38xCD3 IgM dose-dependently inhibits disseminated tumor growth in vivo Two million luciferase-tagged NCI-H929 (B lymphocytes isolated by malignant effusion from a 62-year-old female patient with plasmacytoma multiple myeloma) cells were injected intravenously into 7-8 week-old female NSG mice provided by Jackson Laboratory. The day of tumor inoculation was considered as D0 of the study. Then, 20 million in vitro expanded human pan-T cells were injected 6 days after tumor implantation. 24 hours after T cell implantation, animals were given vehicle, CD38×CD3 IgG, or IgM B-2 treatment at different dose levels every 3 days. Tumor growth was monitored weekly by bioluminescence imaging. Prior to imaging, animals were injected intraperitoneally with 150 μg / kg D-luciferin (Promega). Animals were imaged 15 min later using a SonoVol STRATA imaging device, and imaging was continued on D6, D7, and D8. 12 , D 20 , D 26 and D. 33 Went there.

[0239] Fresh blood samples were collected by retro-orbital bleeding 5 days after the first antibody treatment for flow analysis. Some animals were also sacrificed to collect bone marrow and spleen for flow analysis. T cells were identified in blood, bone marrow and spleen samples by lineage markers (CD3, CD4, CD8) and cell counts were quantified using spiked counting beads.

[0240] FIG. 9A shows the median BLI signal (tumor burden) over time for animals receiving vehicle, CD38×CD3 IgG, or IgM B-2.

[0241] Figures 10A-10F show the BLI signal (tumor burden) over time for each of the animals treated with vehicle (Figure 10A), 0.5 mg / kg CD38xCD3 IgG (Figure 10B), 0.1 mg / kg CD38xCD3 IgG (Figure 10C), 10 mg / kg IgM B-2 (Figure 10D), 3 mg / kg IgM B-2 (Figure 10E), or 1 mg / kg IgM B-2 (Figure 10F).

[0242] These data indicate that IgM B-2 treatment produced a dose-dependent tumor suppressive effect.

[0243] 11A-B show the number of CD4+ T cells (A) and CD8+ T cells (B) per microliter of blood in mice treated with vehicle, 0.5 or 0.1 mg / kg CD38xCD3 IgG, or 10, 3 or 1 mg / kg IgM B-2.

[0244] 12A-B show the numbers of CD4+ T cells (A) and CD8+ T cells (B) per bone marrow sample from mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2.

[0245] 13A-B show the number of CD4+ T cells (A) and CD8+ T cells (B) per mg of spleen samples from mice treated with vehicle, 0.5 mg / kg CD38xCD3 IgG, or 3 mg / kg IgM B-2.

[0246] FIG. 14A shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in peripheral blood of mice treated with vehicle, 0.1 or 0.5 mg / kg CD38×CD3 IgG, or 1, 3, or 10 mg / kg IgM B-2.

[0247] FIG. 14B shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in the bone marrow of mice treated with vehicle, 0.5 mg / kg CD38×CD3 IgG, or 3 mg / kg IgM B-2.

[0248] FIG. 14C shows the ratio of CD8+ T cells to regulatory T cells (Treg) (CD8+T:Treg) in the spleens of mice treated with vehicle, 0.5 mg / kg CD38×CD3 IgG, or 3 mg / kg IgM B-2.

[0249] These data indicate that IgM B-2 treatment reduced T cell-cell combat compared to CD38xCD3 IgG, as IgM B-2-treated mice showed higher T cell counts in peripheral blood, bone marrow, and spleen.

[0250] This study was repeated with four cohorts of 10 mice each, except that IGM B-2 was administered only seven times instead of nine times (D7, D 10 , D 13 , D 16 , D 19 , D 22 and D. 25 The mice were photoimaged using Living Image 4.7.1 (PERKIN ELMER, Waltham, Massachusetts). The other experimental conditions were the same as above. Figure 9B shows the last day when all mice were still alive, D 26 Figure 1 shows tumor growth during the duration of this study up to 24 h. Dose-dependent tumor regression was observed in the treatment groups, however none were statistically significant compared to the vehicle control group (p>0.009).

[0251] Example 14: Complement-dependent cytotoxicity of CD38×CD3 IgM Complement-dependent cytotoxicity (CDC) was measured in a plate-based assay. Briefly, various cell lines exhibiting different susceptibility to CDC, including MOLP-8 (multiple myeloma, DSMZ Catalog No. ACC 569), LP-1 (multiple myeloma, DSMZ Catalog No. ACC 41), Ramos (Burkitt's lymphoma, ATCC Catalog No. CRL-1596), Raji (Burkitt's lymphoma, ATCC Catalog No. CCL-86), RPMI-8226 (multiple myeloma, ATCC Catalog No. CCL-155), NCI-H929 (multiple myeloma, ATCC Catalog No. CRL-9068), OPM-2 (multiple myeloma, DSMZ Catalog No. ACC 50), and MOLM-13 (acute myeloid leukemia, DSMZ Catalog No. ACC 554), were washed and incubated at 1.0 × 10 6Cells were resuspended in assay medium (RPMI1640 medium with 10% heat-inactivated FBS) at a cell density of 10000 cells / mL and placed in wells of a 384-well plate (Thermo, Cat. No. 164610) at 10 μL / well. Purified antibodies IgM B-2, CD38 IgG#Y, and CD38 IgG#Z, as well as an IgM isotype control antibody, were diluted to 90 or 30 μg / mL in medium, then serially diluted 3-fold and 10 μL / well were added to the cells in the 384-well plate. Normal human serum complement (NHS; Quidel, Cat. No. A113) was diluted to 30% in medium and 10 μL / well was added to the cell-antibody mixture in the 384-well plate. Plates were incubated at 37°C in a humidified 5% CO2 incubator for 4 hours. Cell viability was determined by adding 15 μL / well of CellTiter-Glo reagent (Promega, Cat. No. G7572), which generates a luminescent signal directly proportional to the amount of ATP produced by metabolically active cells. After gentle mixing on a plate shaker (2 min, 200 rpm) followed by a 10 min incubation at room temperature, luminescence data were collected on an EnVision plate reader (Perkin-Elmer) and analyzed in GraphPad Prism using a four-parameter logistic model.

[0252] The results are shown in Figures 15A-H. These data demonstrate that IgM B-2 exhibited superior CDC killing in MM cell lines that are sensitive to CDC.

[0253] Example 15: CD38xCD3 IgM exhibits reduced immune effector cell killing compared to CD38xCD3 IgG in vitro. In vitro primary NK cells (donor ID W070522201466) and primary monocytes (donor ID W070522201313) were treated with serial dilutions of CD38xCD3 IgG, or IgM B-2. An irrelevant IgM (AB852) was included as a negative control. Immune effector cell viability was assessed at 72 hours by flow cytometry analysis to quantify surviving immune effector cells. Viable cell counts per well were then normalized to untreated control wells.

[0254] Figure 16A shows that IgM B-2 kills fewer NK cells compared to CD38xCD3 IgG, and Figure 16B shows that IgM B-2 kills fewer monocytes compared to CD38xCD3 IgG.

[0255] Example 15: Antitumor effect of IgM B-2 in a disseminated NCI-H929-luc-gfp-Puro tumor model in PBMC-humanized NSG-MHC I / II DKO mice The antitumor efficacy of IgM B-2 was evaluated in a humanized CD38-positive NCI-H929-luc-gfp-Puro model using NSG-MHC I / II DKO mice, which are deficient in MHC class I and class II expression. When engrafted with human donor PBMCs, these mice exhibit delayed and slower onset of graft-versus-host disease (GVHD) and a longer induction of the effector phase of T cell responses compared to normal NSG mice.

[0256] The day of tumor inoculation was considered as D0 of the study. -14 On D3, each mouse was intravenously implanted with 10 million healthy human PBMCs (purchased from IQ BIOSCIENCES). On D3, cohorts of 8 mice each were either treated with vehicle or with IgM B-2 administered intravenously at 10 mg / kg for 11 doses with antibody dosing 3 times per week (Figure 17) for 15 weeks. Control cohorts received vehicle alone for only 10 weeks. Animals under study were treated with 2000 mm3 The tumor reached a tumor endpoint of 10 days. Animals were injected intraperitoneally with 150 μg / kg D-luciferin (Promega) prior to imaging. Animals were imaged 15 min later using a SonoVol STRATA imager. Images were taken on D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23, D24, D25, D26, D27, D28, D29, D30, D31, D32, D33, D34, D35, D40, D41, D42, D43, D44, D45, D50, D51, D52, D63, D64, D65, D76, D86, D97, D98, D109, 10 , D 15 , D 20 , D 24 , D 29 and D. 34 Went there.

[0257] Figure 17 shows the effect of treatment with IGM B-2 in this disseminated NCI-H929-luc-gfp-Puro tumor model in PBMC-humanized NSG-MHC I / II DKO mice. Error bars represent the mean ± standard error of 9 animals per group. Statistical analysis (Kruskal-Wallis test with Dunn's test for multiple comparisons) represents a comparison with the vehicle control group. Each vertical line indicates the day of antibody dosing. Tumor regression in the 10 mg / kg treatment group was not statistically significant (p=0.45) compared to the vehicle group.

[0258] Example 16: Antitumor effect of IgM B-2 in a multiple myeloma model in PBMC-humanized NSG-MHC I / II DKO mice The antitumor effect of IGM B-2 was evaluated in a CD38-positive subcutaneous multiple myeloma xenograft model in PBMC-humanized NSG-MHC I / II DKO mice. Five million NCI-H929-gfp-luc-puro cells were subcutaneously implanted into the right flank of NSG-MHC I / II DKO mice. Cells were implanted in PBS at a volume of 100 μL / mouse. The day of tumor inoculation was considered as D0 of the study. -14 Each mouse was then intravenously transplanted with 10 million healthy human PBMCs (purchased from IQ BIOSCIENCES). Animals were administered either vehicle or IGM B-2 intravenously at 1, 3, 10 and 30 mg / kg for 15 doses three times a week.

[0259] Tumors were measured using calipers and tumor volume was calculated using the formula TV = (L × W), where L is the tumor length (longest tumor dimension) and W is the tumor width.2 Body weight (BW) and tumors were measured twice weekly and animals under study were monitored daily for signs of morbidity and mortality. Dosing, blood sampling, tumor and BW measurements were performed in a laminar flow cabinet. Individual animals were cultured at 2000 mm 3 Animals were euthanized when they reached a tumor volume of 0.01 mm and a body condition score (BCS) of 0.01 mm or less. Animals experiencing greater than 10% body weight loss (BWL) were administered lactated Ringer's solution (LRS) and offered hydrogel cups and softened food pellets. They were monitored daily and euthanized if their BWL was greater than 20% of their BW at the start of the study (day of first tumor measurement).

[0260] Dose-dependent tumor regression was observed in all treatment groups (Figure 18A). None of the animals exhibited any weight loss (Figure 18B). Animals in the vehicle group did not show any significant weight loss after 10 days of treatment (Figure 18C). 28 2000mm by 3 The tumor endpoint was reached, but animals in the treatment groups were monitored for survival to ensure the study was 49 At the end of the study, there was one tumor-free mouse in each of the 30 mg / kg and 10 mg / kg groups. Treatment with IGM B-2 at 30 mg / kg and 10 mg / kg extended median overall survival by 12 and 13.5 days, respectively, compared to the vehicle-treated group (Figure 18C).

[0261] D in the exam 21 Comparison of tumor volumes in the 30 mg / kg group (p=0.0049) and 10 mg / kg group (p=0.0045) yielded statistically significant p-values ​​compared to the vehicle group ( FIG. 18D ). 21 The tumor growth inhibition percentage (TGI%) was calculated. The 30 mg / kg group showed the highest TGI% of 81.9%. In contrast, the 10, 3 and 1 mg / kg groups showed TGI% of 80%, 63.8% and 63.6%, respectively.

[0262] Example 17: Antitumor effect of IgM B-2 in a humanized CD38-positive Raji xenograft tumor model Lymphoblastoid cells of the Raji lineage were established from Burkitt's lymphoma. Three million Raji cells were subcutaneously implanted into the right flank of each of five cohorts of NSG-MHC I / II DKO mice (9 mice / cohort). Cells were implanted in 1×PBS at a volume of 100 μL / mouse. The day of tumor inoculation was considered as D0 of the study.

[0263] D -14 Each mouse was intravenously implanted with 10 million healthy human PBMCs (purchased from IQ BIOSCIENCES) on D3. On D4, animals were intravenously administered either vehicle or IgM B-2 at 30, 10, 3 and 1 mg / kg, three times per week for 15 doses. The control cohort received vehicle alone three times per week for only 10 weeks. The animals under study were implanted with 2000 mm 3 The tumor endpoint was reached.

[0264] Tumors were measured using calipers and tumor volume was calculated using the formula TV = (L × W 2 ) / 2. BW and tumors were measured twice weekly and animals under study were monitored daily for signs of morbidity and mortality. Dosing, blood sampling, tumor and BW measurements were performed in a laminar flow cabinet. Individual animals were cultured at 2000 mm 3 Animals were euthanized when they reached a tumor volume of 0.01 mm and a BCS score of 0.01 mm or less. Animals experiencing a BWL of >10% were administered lactate LRS and provided with hydrogel cups and softened food pellets. They were monitored daily and euthanized if their BWL was >20% of their BW at the start of the study (day of first tumor measurement).

[0265] Tumor volumes were compared between treatment groups using the Kruskal-Wallis test with Dunn's test for multiple comparisons. Survival curves were assessed using the Kaplan-Meier method, and treatment groups were compared using the log-rank (Mantel-Cox) test. Statistical analysis was performed using GraphPad Prism 8 software. For all statistical tests performed, a two-sided P value <0.05 was considered statistically significant.

[0266] Tumor growth inhibition was calculated as (1-(T n -T0) / (Cn-C0) × 100 (where T n = mean tumor volume of treatment group on day n, T0 = mean tumor volume of treatment group on day 7, C n = mean tumor volume of the control group on day n, and C0 = mean tumor volume of the control group on day 7).

[0267] Dose-dependent tumor regression was observed in all treatment groups (Figure 19A). 25 Comparison of tumor volumes in the 30 mg / kg group (p<0.0001) and 10 mg / kg group (p=0.0008) yielded statistically significant p-values ​​compared to the vehicle group ( FIG. 19B ). 25 The tumor growth inhibition percentage (TGI%) was calculated at the time of administration, when 8 / 9 mice in the vehicle group were still alive. The highest dose group, 30 mg / kg, showed the highest TGI% of 66.4%. In contrast, 10, 3 and 1 mg / kg showed TGI% of 54.5%, 33.4% and 26.8%, respectively.

[0268] None of the animals exhibited any weight loss (Figure 19C). 27 2000mm by 3 The tumor endpoint was reached, but animals in the treatment groups were monitored for survival to ensure the study was 63 At the end of the study, there was one tumor-free mouse in the 30 mg / kg group and two tumor-free mice in the 3 mg / kg group. Treatment with 30 mg / kg IGM B-2 extended median overall survival by 18 days compared to the vehicle-treated group (Figure 19D).

[0269] Table 17. Exemplary CD3-binding agent sequences TIFF2025506341000023.tif179170TIFF2025506341000024.tif201170

[0270] Table 18: Other disclosed sequences TIFF2025506341000025.tif22170TIFF2025506341000026.tif236170TIFF2025506341000027.tif237170TIFF2025506341000028.tif231170

Claims

1. An antibody or antigen-binding fragment or derivative thereof comprising an antigen-binding domain that specifically binds to CD38, the antigen-binding domain comprises a heavy chain variable region (VH) and a light chain variable region (VL); the VH and the VL comprise six immunoglobulin complementarity determining regions HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3; the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 are each SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:73, SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:81, SEQ ID NO:82, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:109, SEQ ID NO:110 and SEQ ID NO:111; SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:117, SEQ ID NO:118 and SEQ ID NO:119; SEQ ID NO:121, SEQ ID NO:122, SEQ ID NO:123, SEQ ID NO:125, SEQ ID NO:126 and SEQ ID NO:127; SEQ ID NO:65, SEQ ID NO:134, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:182, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:135, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:143, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:144, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:145, SEQ ID NO:94 and SEQ ID NO:95; or SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95 comprising the amino acid sequence The antibody or an antigen-binding fragment or derivative thereof.

2. the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 comprise the amino acid sequences of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, respectively; 2. The antibody or antigen-binding fragment or derivative thereof described in claim 1.

3. The VH and the VL are each SEQ ID NO:128 and SEQ ID NO:133; SEQ ID NO:56 and SEQ ID NO:60; SEQ ID NO:64 and SEQ ID NO:68; SEQ ID NO:72 and SEQ ID NO:76; SEQ ID NO:80 and SEQ ID NO:84; SEQ ID NO:88 and SEQ ID NO:92; SEQ ID NO:96 and SEQ ID NO:100; SEQ ID NO:104 and SEQ ID NO:108; SEQ ID NO:112 and SEQ ID NO:116; SEQ ID NO:120 and SEQ ID NO:124; SEQ ID NO:128 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:133; SEQ ID NO:130 and SEQ ID NO:68; SEQ ID NO:130 and SEQ ID NO:133; SEQ ID NO:131 and SEQ ID NO:68; SEQ ID NO:131 and SEQ ID NO:133; SEQ ID NO:132 and SEQ ID NO:68; SEQ ID NO:132 and SEQ ID NO:133; SEQ ID NO:64 and SEQ ID NO:133; SEQ ID NO:136 and SEQ ID NO:86; SEQ ID NO:136 and SEQ ID NO:138; SEQ ID NO:136 and SEQ ID NO:139; SEQ ID NO:136 and SEQ ID NO:140; SEQ ID NO:136 and SEQ ID NO:141; SEQ ID NO:136 and SEQ ID NO:142; SEQ ID NO:137 and SEQ ID NO:86; SEQ ID NO:137 and SEQ ID NO:138; SEQ ID NO:137 and SEQ ID NO:139; SEQ ID NO:137 and SEQ ID NO:140; SEQ ID NO:137 and SEQ ID NO:141; SEQ ID NO:137 and SEQ ID NO:142; SEQ ID NO:88 and SEQ ID NO:138; SEQ ID NO:88 and SEQ ID NO:139; SEQ ID NO:88 and SEQ ID NO:140; SEQ ID NO:88 and SEQ ID NO:141; or SEQ ID NO:88 and SEQ ID NO:142 comprising an amino acid sequence that is at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequence of 3. An antibody or antigen-binding fragment or derivative thereof according to claim 1 or claim 2.

4. The VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO: 128 and SEQ ID NO: 133, respectively; The antibody or antigen-binding fragment or derivative thereof described in claim 3.

5. An antibody or antigen-binding fragment or derivative thereof comprising an antigen-binding domain that specifically binds to CD38, the antigen-binding domain comprises a heavy chain variable region (VH) and a light chain variable region (VL); The VH and the VL are each SEQ ID NO:147 and SEQ ID NO:150; SEQ ID NO:147 and SEQ ID NO:151; SEQ ID NO:147 and SEQ ID NO:152; SEQ ID NO:147 and SEQ ID NO:153; SEQ ID NO:147 and SEQ ID NO:154; SEQ ID NO:147 and SEQ ID NO:155; SEQ ID NO:148 and SEQ ID NO:150; SEQ ID NO:148 and SEQ ID NO:151; SEQ ID NO:148 and SEQ ID NO:152; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:154; SEQ ID NO:148 and SEQ ID NO:155; SEQ ID NO:149 and SEQ ID NO:150; SEQ ID NO:149 and SEQ ID NO:151; SEQ ID NO:149 and SEQ ID NO:152; SEQ ID NO:149 and SEQ ID NO:153; SEQ ID NO:149 and SEQ ID NO:154; SEQ ID NO:149 and SEQ ID NO:155; SEQ ID NO:156 and SEQ ID NO:159; SEQ ID NO:156 and SEQ ID NO:160; SEQ ID NO:156 and SEQ ID NO:161; SEQ ID NO:157 and SEQ ID NO:159; SEQ ID NO:157 and SEQ ID NO:160; SEQ ID NO:157 and SEQ ID NO:161; SEQ ID NO:158 and SEQ ID NO:159; SEQ ID NO:158 and SEQ ID NO:160; or SEQ ID NO: 158 and SEQ ID NO: 161 comprising the amino acid sequence The antibody or an antigen-binding fragment or derivative thereof.

6. a multimeric antibody comprising 2, 4, 5 or 6 bivalent binding units and 4, 8, 10 or 12 antigen-binding domains, at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 antigen-binding domains specifically bind to CD38; each binding unit comprises two heavy chains, each of which comprises an IgA or IgM constant region, or a multimerizing fragment or variant thereof; at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 heavy chain constant regions or fragments or variants thereof are associated with said copy of VH; An antibody or an antigen-binding fragment or derivative thereof according to any one of claims 1 to 5.

7. Fv fragment, single chain Fv fragment (scFv) or disulfide-linked Fv fragment (sdFv); An antibody or an antigen-binding fragment or derivative thereof according to any one of claims 1 to 5.

8. Complete antibody, Fab fragment, Fab' fragment or F(ab') ２ Contains fragments, An antibody or an antigen-binding fragment or derivative thereof according to any one of claims 1 to 5.

9. a bivalent binding unit comprising two antigen-binding domains, at least one antigen-binding domain specifically binds to CD38; the binding unit comprises two heavy chains, each of which comprises a heavy chain constant region or a fragment or variant thereof; At least one heavy chain constant region, or a fragment or variant thereof, is associated with said copy of VH.

9. An antibody or antigen-binding fragment or derivative thereof according to claim 8.

10. the heavy chain comprises an IgG heavy chain constant region, or a fragment or variant thereof, fused to the C-terminus of the VH; 10. An antibody or antigen-binding fragment or derivative thereof according to claim 9.

11. the binding unit further comprises two light chains each comprising a light chain constant region or a fragment or variant thereof fused to the C-terminus of the VL; 11. An antibody or antigen-binding fragment or derivative thereof according to claim 10.

12. A multimeric antibody comprising 2, 4, 5 or 6 bivalent binding units, each binding unit comprises two IgM or IgA heavy chain constant regions, or multimerizing fragments or variants thereof, each associated with an antigen-binding domain; at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 of the antigen-binding domains are CD38 antigen-binding domains comprising a heavy chain variable region (VH) and a light chain variable region (VL); the VH and the VL comprise six immunoglobulin complementarity determining regions HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3; the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 are each SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:57, SEQ ID NO:58, SEQ ID NO:59, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; SEQ ID NO:73, SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:78 and SEQ ID NO:79; SEQ ID NO:81, SEQ ID NO:82, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:86 and SEQ ID NO:87; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:93, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:101, SEQ ID NO:102 and SEQ ID NO:103; SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:109, SEQ ID NO:110 and SEQ ID NO:111; SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:117, SEQ ID NO:118 and SEQ ID NO:119; SEQ ID NO:121, SEQ ID NO:122, SEQ ID NO:123, SEQ ID NO:125, SEQ ID NO:126 and SEQ ID NO:127; SEQ ID NO:65, SEQ ID NO:134, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:182, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:65, SEQ ID NO:135, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:143, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:144, SEQ ID NO:94 and SEQ ID NO:95; SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:145, SEQ ID NO:94 and SEQ ID NO:95; or SEQ ID NO:89, SEQ ID NO:90, SEQ ID NO:91, SEQ ID NO:146, SEQ ID NO:94 and SEQ ID NO:95 comprising the amino acid sequence The multimeric antibody.

13. more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and the VL of the multimeric antibody; The multimeric antibody of claim 12.

14. and capable of inducing complement-dependent cytotoxicity (CDC) of CD38-expressing cells with greater potency than an equivalent amount of a bivalent IgG antibody comprising the VH and the VL of the multimeric antibody. The multimeric antibody of claim 13.

15. the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 comprise the amino acid sequences of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, respectively; A multimeric antibody according to any one of claims 12 to 14.

16. The VH and the VL are each SEQ ID NO:128 and SEQ ID NO:133; SEQ ID NO:56 and SEQ ID NO:60; SEQ ID NO:64 and SEQ ID NO:68; SEQ ID NO:72 and SEQ ID NO:76; SEQ ID NO:80 and SEQ ID NO:84; SEQ ID NO:88 and SEQ ID NO:92; SEQ ID NO:96 and SEQ ID NO:100; SEQ ID NO:104 and SEQ ID NO:108; SEQ ID NO:112 and SEQ ID NO:116; SEQ ID NO:120 and SEQ ID NO:124; SEQ ID NO:128 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:68; SEQ ID NO:129 and SEQ ID NO:133; SEQ ID NO:130 and SEQ ID NO:68; SEQ ID NO:130 and SEQ ID NO:133; SEQ ID NO:131 and SEQ ID NO:68; SEQ ID NO:131 and SEQ ID NO:133; SEQ ID NO:132 and SEQ ID NO:68; SEQ ID NO:132 and SEQ ID NO:133; SEQ ID NO:64 and SEQ ID NO:133; SEQ ID NO:136 and SEQ ID NO:86; SEQ ID NO:136 and SEQ ID NO:138; SEQ ID NO:136 and SEQ ID NO:139; SEQ ID NO:136 and SEQ ID NO:140; SEQ ID NO:136 and SEQ ID NO:141; SEQ ID NO:136 and SEQ ID NO:142; SEQ ID NO:137 and SEQ ID NO:86; SEQ ID NO:137 and SEQ ID NO:138; SEQ ID NO:137 and SEQ ID NO:139; SEQ ID NO:137 and SEQ ID NO:140; SEQ ID NO:137 and SEQ ID NO:141; SEQ ID NO:137 and SEQ ID NO:142; SEQ ID NO:88 and SEQ ID NO:138; SEQ ID NO:88 and SEQ ID NO:139; SEQ ID NO:88 and SEQ ID NO:140; SEQ ID NO:88 and SEQ ID NO:141; or SEQ ID NO:88 and SEQ ID NO:142 comprising an amino acid sequence that is at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequence of A multimeric antibody according to any one of claims 12 to 14.

17. The VH and VL comprise amino acid sequences that are at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequences of SEQ ID NO: 128 and SEQ ID NO: 133, respectively; The multimeric antibody of claim 16.

18. A multimeric antibody comprising 2, 4, 5 or 6 bivalent binding units, each binding unit comprises two IgM or IgA heavy chain constant regions, or multimerizing fragments or variants thereof, each associated with an antigen-binding domain; at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 of the antigen-binding domains are CD38 antigen-binding domains comprising a heavy chain variable region (VH) and a light chain variable region (VL); The VH and the VL are each SEQ ID NO:147 and SEQ ID NO:150; SEQ ID NO:147 and SEQ ID NO:151; SEQ ID NO:147 and SEQ ID NO:152; SEQ ID NO:147 and SEQ ID NO:153; SEQ ID NO:147 and SEQ ID NO:154; SEQ ID NO:147 and SEQ ID NO:155; SEQ ID NO:148 and SEQ ID NO:150; SEQ ID NO:148 and SEQ ID NO:151; SEQ ID NO:148 and SEQ ID NO:152; SEQ ID NO:148 and SEQ ID NO:153; SEQ ID NO:148 and SEQ ID NO:154; SEQ ID NO:148 and SEQ ID NO:155; SEQ ID NO:149 and SEQ ID NO:150; SEQ ID NO:149 and SEQ ID NO:151; SEQ ID NO:149 and SEQ ID NO:152; SEQ ID NO:149 and SEQ ID NO:153; SEQ ID NO:149 and SEQ ID NO:154; SEQ ID NO:149 and SEQ ID NO:155; SEQ ID NO:156 and SEQ ID NO:159; SEQ ID NO:156 and SEQ ID NO:160; SEQ ID NO:156 and SEQ ID NO:161; SEQ ID NO:157 and SEQ ID NO:159; SEQ ID NO:157 and SEQ ID NO:160; SEQ ID NO:157 and SEQ ID NO:161; SEQ ID NO:158 and SEQ ID NO:159; SEQ ID NO:158 and SEQ ID NO:160; or SEQ ID NO: 158 and SEQ ID NO: 161 comprising the amino acid sequence The multimeric antibody.

19. more potent than an equivalent amount of a bivalent IgG antibody comprising the VH and the VL of the multimeric antibody; The multimeric antibody of claim 18.

20. The multimeric antibody can induce complement-dependent cytotoxicity (CDC) of CD38-expressing cells with higher potency than an equivalent amount of a bivalent IgG antibody comprising the VH and the VL of the multimeric antibody.

20. The multimeric antibody of claim 19.

21. is a dimer or a tetramer, comprising two or four bivalent IgA or IgA-like binding units and a J chain or a fragment or variant thereof; Each binding unit comprises two IgA heavy chain constant regions, each of which comprises a Cα3 domain and an α tailpiece (αtp) domain, or a multimerizing fragment or variant thereof; A multimeric antibody according to any one of claims 12 to 20.

22. Each of the IgA heavy chain constant regions or multimerizing fragments or variants thereof further comprises a Cα1 domain, a Cα2 domain, an IgA hinge region, or any combination thereof. The multimeric antibody of claim 21.

23. The IgA heavy chain constant region, or a multimerizing fragment or variant thereof, is a human IgA constant region. A multimeric antibody according to claim 21 or claim 22.

24. The J chain is a mature human J chain comprising the amino acid sequence of SEQ ID NO: 7 or a functional fragment or variant thereof. A multimeric antibody according to any one of claims 21 to 23.

25. is a hexamer or a pentamer, comprising five or six bivalent IgM or IgM-like binding units, Each binding unit comprises two IgM heavy chain constant regions, each of which comprises a Cμ4 and μ tailpiece (μtp) domain, or a multimerizing fragment or variant thereof; A multimeric antibody according to any one of claims 12 to 19.

26. each of said IgM heavy chain constant regions or fragments or variants thereof further comprises a Cμ1 domain, a Cμ2 domain, a Cμ3 domain, or any combination thereof; The multimeric antibody of claim 25.

27. The IgM heavy chain constant region, or a multimerizing fragment or variant thereof, is a human IgM constant region. A multimeric antibody according to claim 25 or claim 26.

28. each IgM heavy chain constant region comprises the amino acid sequence SEQ ID NO:1, SEQ ID NO:2, or a multimerizing variant or fragment thereof; The multimeric antibody of claim 27.

29. each IgM heavy chain constant region is a variant human IgM constant region comprising one or more single amino acid substitutions, deletions or insertions compared to SEQ ID NO:1 or SEQ ID NO:2; The multimeric antibody has a reduced CDC activity compared to a multimeric antibody comprising the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 in each IgM heavy chain constant region. A multimeric antibody according to claim 27 or claim 28.

30. Each variant human IgM constant region is an amino acid substitution corresponding to position L310 of SEQ ID NO: 1 or SEQ ID NO: 2; an amino acid substitution corresponding to position P311 of SEQ ID NO: 1 or SEQ ID NO: 2; an amino acid substitution corresponding to position P313 of SEQ ID NO: 1 or SEQ ID NO: 2; an amino acid substitution corresponding to position K315 of SEQ ID NO:1 or SEQ ID NO:2, or including any combination thereof, 30. The multimeric antibody of claim 29.

31. each IgM heavy chain constant region is a variant human IgM constant region comprising one or more single amino acid substitutions, deletions or insertions compared to SEQ ID NO:1 or SEQ ID NO:2; When administered to a subject animal, the multimeric antibody exhibits an increased serum half-life compared to a multimeric antibody comprising the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 in each IgM heavy chain constant region administered in the same manner to the same animal species. A multimeric antibody according to any one of claims 27 to 30.

32. the variant IgM heavy chain constant region comprises a half-life altering amino acid substitution at one or more amino acid positions corresponding to amino acids E345, S401, E402 or E403 of SEQ ID NO:1 or SEQ ID NO:2; The multimeric antibody of claim 31.

33. It is a pentamer, Further comprising a J chain or a functional fragment or a functional variant thereof; A multimeric antibody according to any one of claims 25 to 32.

34. The J chain is a mature human J chain comprising the amino acid sequence of SEQ ID NO: 7 or a functional fragment or variant thereof. The multimeric antibody of claim 33.

35. the J chain is a variant J chain or a functional fragment thereof that contains one or more single amino acid substitutions, deletions or insertions compared to a reference J chain, the reference J chain being identical to the variant J chain except for the one or more single amino acid substitutions, deletions or insertions; the variant J chain is capable of affecting the serum half-life of the multimeric antibody; when administered to a subject animal, said multimeric antibody exhibits an increased serum half-life compared to a reference multimeric antibody that is identical except for said one or more single amino acid substitutions, deletions or insertions in said variant J chain and administered in the same manner to the same animal species. The multimeric antibody of claim 33.

36. the variant J chain comprises an amino acid substitution at an amino acid position corresponding to amino acid Y102 of the wild-type mature human J chain of SEQ ID NO:7; The multimeric antibody of claim 35.

37. The amino acid corresponding to Y102 in SEQ ID NO:7 is replaced with alanine (A); The multimeric antibody of claim 36.

38. the J chain comprises the amino acid sequence of SEQ ID NO:8; 38. The multimeric antibody of claim 37.

39. the J chain or functional fragment thereof is a modified J chain further comprising a heterologous moiety; the heterologous moiety is fused or conjugated to the J chain or a functional fragment or variant thereof; A multimeric antibody according to any one of claims 24 or 33 to 38.

40. the heterologous moiety is a polypeptide fused to the J chain or a functional fragment or variant thereof; 40. The multimeric antibody of claim 39.

41. the heterologous polypeptide is fused to the J chain, or a functional fragment or variant thereof, via a peptide linker comprising at least 5 amino acids but not more than 25 amino acids. The multimeric antibody of claim 40.

42. The heterologous polypeptide is the N-terminus of the J chain or a functional fragment or variant thereof; the C-terminus of the J chain or a functional fragment or variant thereof; or Both the N-terminus and the C-terminus of the J chain or a functional fragment or variant thereof It is fused with The heterologous polypeptides fused to both the N-terminus and the C-terminus can be the same or different. A multimeric antibody according to claim 40 or claim 41.

43. The multimeric antibody of any one of claims 40 to 42, wherein the heterologous polypeptide comprises an scFv fragment.

44. The multimeric antibody of claim 43, wherein the heterologous scFv fragment binds to CD3.

45. the scFv fragment comprises an scFv heavy chain variable region (scFv VH) and an scFv light chain variable region (scFv VL); the scFv VH comprises scFv VH complementarity determining regions VHCDR1, VHCDR2 and VHCDR3; the scFv VL comprises scFv VL complementarity determining regions VLCDR1, VLCDR2 and VLCDR3; the VHCDR1, the VHCDR2, the VHCDR3, the VLCDR1, the VLCDR2 and the VLCDR3 are each SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:21, SEQ ID NO:22 and SEQ ID NO:23; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30 and SEQ ID NO:31; SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30 and SEQ ID NO:33; SEQ ID NO:35, SEQ ID NO:36, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40 and SEQ ID NO:41; SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:37, SEQ ID NO:39, SEQ ID NO:40 and SEQ ID NO:45; or SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:47, SEQ ID NO:39, SEQ ID NO:40 and SEQ ID NO:49 comprising the amino acid sequence 45. The multimeric antibody of claim 44.

46. the VHCDR1, the VHCDR2, the VHCDR3, the VLCDR1, the VLCDR2 and the VLCDR3 comprise SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:29, SEQ ID NO:30 and SEQ ID NO:31, respectively; 46. ​​The multimeric antibody of claim 45.

47. The scFv VH and the scFv VL each comprise: SEQ ID NO:16 and SEQ ID NO:20; SEQ ID NO:24 and SEQ ID NO:28; SEQ ID NO:24 and SEQ ID NO:32; SEQ ID NO:34 and SEQ ID NO:38; SEQ ID NO:42 and SEQ ID NO:44; or SEQ ID NO:46 and SEQ ID NO:48 comprising an amino acid sequence that is at least 80%, 85%, 90%, 95% or 100% identical to the amino acid sequence of 46. ​​The multimeric antibody of claim 45.

48. The scFv fragment comprises the scFv VH and scFv VL amino acid sequences of SEQ ID NO:24 and SEQ ID NO:28, respectively; 48. The multimeric antibody of claim 47.

49. capable of specifically binding to human CD38, non-human primate CD38, or human CD38 and non-human primate CD38; An antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11, or a multimeric antibody according to any one of claims 12 to 48.

50. The non-human primate CD38 is cynomolgus monkey CD38.

50. An antibody or antigen-binding fragment or derivative thereof according to claim 49, or a multimeric antibody according to claim 49.

51. specifically binds CD38 with an affinity characterized by a dissociation constant KD of 500 nM, 100 nM, 50.0 nM, 40.0 nM, 30.0 nM, 20.0 nM, 10.0 nM, 9.0 nM, 8.0 nM, 7.0 nM, 6.0 nM, 5.0 nM, 4.0 nM, 3.0 nM, 2.0 nM, 1.0 nM, 0.50 nM, 0.10 nM, 0.050 nM, 0.01 nM, 0.005 nM, or 0.001 nM or less; The CD38 is human CD38, cynomolgus monkey CD38, or human CD38 and cynomolgus monkey CD38; An antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 50, or a multimeric antibody according to any one of claims 12 to 50.

52. It is multispecific, An antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 51, or a multimeric antibody according to any one of claims 12 to 51.

53. It is bispecific, 53. An antibody or antigen-binding fragment or derivative thereof according to claim 52, or a multimeric antibody according to claim 52.

54. A composition comprising an antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, or a multimeric antibody according to any one of claims 12 to 53.

55. A polynucleotide comprising a nucleic acid sequence encoding the antibody or antigen-binding fragment or derivative thereof of any one of claims 1 to 11 or 49 to 53, or the multimeric antibody of any one of claims 12 to 53.

56. A vector comprising the polynucleotide of claim 55.

57. A host cell comprising the vector of claim 56.

58. A method for producing an antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, or a multimeric antibody according to any one of claims 12 to 53, comprising the steps of: Culturing the host cell of claim 57; and recovering said antibody or antigen-binding fragment or derivative thereof. The method comprising:

59. 1. A method of treating cancer, comprising: Administering to a subject in need of treatment an effective amount of an antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, or a multimeric antibody according to any one of claims 12 to 53. The method comprising:

60. 60. The method of claim 59, wherein the subject is a human.

61. For use in treating cancer in a subject in need thereof. An antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, a multimeric antibody according to any one of claims 12 to 53, or a composition according to claim 54.

62. 62. The antibody or antigen-binding fragment or derivative thereof, multimeric antibody, or composition for use according to claim 61, wherein the subject is a human.

63. In providing cancer treatment to a subject in need thereof, Use of an antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, or a multimeric antibody according to any one of claims 12 to 53.

64. In the manufacture of a medicament for treating cancer in a subject in need thereof, Use of an antibody or antigen-binding fragment or derivative thereof according to any one of claims 1 to 11 or 49 to 53, or a multimeric antibody according to any one of claims 12 to 53.

65. 65. The use according to claim 63 or claim 64, wherein the subject is a human.

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