CD38 MODULATING ANTIBODY AGENTS

20230103584 · 2023-04-06

    Inventors

    Cpc classification

    International classification

    Abstract

    The present disclosure provides antibody sequences found in antibodies that bind to human CD38. In particular, the present disclosure provides sequences of anti-human CD38 antibodies. Antibodies and antigen-binding portions thereof including such sequences present features compatible with pharmaceutical manufacturing and development can be provided as fully human antibodies (e.g., fully human monoclonal antibodies or antigen-binding fragments) that can be useful for medical methods and compositions, in particular for treating cancer.

    Claims

    1. An antibody or antigen-binding fragment thereof, comprising the aCD38-b-348-HCDR3 amino acid sequence as variable heavy chain complementarity determining region 3.

    2. The antibody or antigen-binding fragment thereof of claim 1, further comprising a) aCD38-b-348-HCDR1 amino acid sequence as variable heavy chain complementarity determining region 1; and b) aCD38-b-348-HCDR2 amino acid sequence as variable heavy chain complementarity determining region 2.

    3. The antibody or antigen-binding fragment thereof of claim 1 or claim 2, further comprising: a) aCD38-b-348-LCDR1 amino acid sequence as variable light chain complementarity determining region 1; b) aCD38-b-348-LCDR2 amino acid sequence as variable light chain complementarity determining region 2; and c) aCD38-b-348-LCDR3 amino acid sequence as variable light chain complementarity determining region 3.

    4. The antibody or antigen-binding fragment thereof of claim 1, 2 or 3, wherein the antibody or antigen-binding fragment thereof comprises a variable heavy chain comprising aCD38-b-348-HCDR 123 amino acid sequence.

    5. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 4, wherein the antibody or antigen-binding fragment thereof further comprises a variable light chain comprising aCD38-b-348-LCDR123 amino acid.

    6. The antibody or antigen-binding fragment thereof according to any one of claims 3 to 5, wherein the antibody or antigen-binding fragment thereof is mutated to remove the DG motif in the LCDR3 region.

    7. The antibody or antigen-binding fragment thereof according to claim 6, wherein the antibody or antigen-binding fragment thereof comprises an LCDR3 region selected from the group consisting of QQEANVYT, QQDSNVYT, QQDANVYT and QQEGNVYT.

    8. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 7 wherein the antibody or an antigen-binding fragment thereof is selected from the group consisting of: a) an antibody or antigen binding fragment thereof comprising an HCDR1 comprising the sequence of SEQ ID NO: 1, an HCDR2 comprising the sequence of SEQ ID NO: 2, an HCDR3 comprising the sequence of SEQ ID NO 3, an LCDR1 comprising the sequence of SEQ ID NO: 5, an LCDR2 comprising the sequence of SEQ ID NO: 6, and an LCDR3 comprising the sequence of SEQ ID NO: 7; b) an antibody or antigen binding fragment thereof comprising an HCDR1 comprising the sequence of SEQ ID NO: 1, an HCDR2 comprising the sequence of SEQ ID NO: 2, an HCDR3 comprising the sequence of SEQ ID NO 3, an LCDR1 comprising the sequence of SEQ ID NO: 5, an LCDR2 comprising the sequence of SEQ ID NO: 6, and an LCDR3 comprising the sequence of SEQ ID NO: 10; c) an antibody or antigen binding fragment thereof comprising an HCDR1 comprising the sequence of SEQ ID NO: 1, an HCDR2 comprising the sequence of SEQ ID NO: 2, an HCDR3 comprising the sequence of SEQ ID NO 3, an LCDR1 comprising the sequence of SEQ ID NO: 5, an LCDR2 comprising the sequence of SEQ ID NO: 5, and an LCDR3 comprising the sequence of SEQ ID NO: 11; d) an antibody or antigen binding fragment thereof comprising an HCDR1 comprising the sequence of SEQ ID NO: 1, an HCDR2 comprising the sequence of SEQ ID NO: 2, an HCDR3 comprising the sequence of SEQ ID NO 3, an LCDR1 comprising the sequence of SEQ ID NO: 5, an LCDR2 comprising the sequence of SEQ ID NO: 6, and an LCDR3 comprising the sequence of SEQ ID NO: 12 e) an antibody or antigen binding fragment thereof comprising an HCDR1 comprising the sequence of SEQ ID NO: 1, an HCDR2 comprising the sequence of SEQ ID NO: 2, an HCDR3 comprising the sequence of SEQ ID NO 3, an LCDR1 comprising the sequence of SEQ ID NO: 5, an LCDR2 comprising the sequence of SEQ ID NO: 6, and an LCDR3 comprising the sequence of SEQ ID NO: 13; f) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 4 and a light chain variable region comprising the sequence of SEQ ID NO: 8; g) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 4 and a light chain variable region comprising the sequence of SEQ ID NO: 20; h) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 4 and a light chain variable region comprising the sequence of SEQ ID NO: 21. i) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 4 and a light chain variable region comprising the sequence of SEQ ID NO: 22; j) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 4 and a light chain variable region comprising the sequence of SEQ ID NO: 23; k) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 14 and a light chain variable region comprising the sequence of SEQ ID NO: 19; l) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 14 and a light chain variable region comprising the sequence of SEQ ID NO: 15; m) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 14 and a light chain variable region comprising the sequence of SEQ ID NO: 16; n) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 14 and a light chain variable region comprising the sequence of SEQ ID NO: 17; and o) an antibody or antigen binding fragment thereof comprising a heavy chain variable region comprising the sequence of SEQ ID NO: 14 and a light chain variable region comprising the sequence of SEQ ID NO: 18.

    9. The antibody or an antigen-binding fragment thereof of any preceding claim wherein the antibody or antigen-binding fragment thereof is a-fucosylated.

    10. An antibody or antigen-binding fragment that specifically binds to an epitope of human CD38, wherein the epitope comprises one or more amino acid residues comprised in amino acids 65-79 of SEQ ID NO: 9.

    11. The antibody or antigen or antigen-binding fragment of claim 10 wherein the epitope comprises amino acids 65-79 of SEQ ID NO: 9.

    12. An affinity matured variant of an antibody or antigen binding fragment thereof of any one of claims 1 to 9.

    13. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 12, wherein the antibody or antigen-binding fragment thereof is a monoclonal antibody, a domain antibody, a single chain antibody, a Fab fragment, a F(ab')2 fragment, a single chain variable fragment (scFv), a scFv-Fc fragment, a single chain antibody (scAb), an aptamer, or a nanobody.

    14. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 13, wherein the antibody or antigen-binding fragment thereof is a rabbit, mouse, chimeric, humanized or fully human antigen-binding antibody.

    15. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 14, wherein the antibody is selected from the group consisting of IgG1, IgG2, IgG3, and IgG4 isotype antibodies.

    16. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 15, wherein the antibody or antigen-binding fragment thereof is comprised in a bispecific antibody, a multispecific antibody, or an immunoconjugate further comprising a therapeutic or diagnostic agent.

    17. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 16, wherein the antibody or antigen-binding fragment thereof binds the extracellular domain of human CD38.

    18. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 17, wherein the antibody or antigen-binding fragment thereof binds cells expressing human CD38 on their surface and is a CD38 Modulating Antibody Agent.

    19. A nucleic acid molecule encoding the antibody or antigen-binding fragment thereof of any of the claims 1 to 18.

    20. A nucleic acid vector comprising the nucleic acid molecule of claim 19.

    21. A host cell comprising the nucleic acid vector of claim 20.

    22. A method for producing an antibody or antigen-binding fragment thereof according to any one of claims 1 to 18 by culturing a host cell of claim 21.

    23. A composition comprising an antibody or antigen-binding fragment thereof according to any one of claims 1 to 18.

    24. The composition of claim 23 that further comprises a pharmaceutically acceptable carrier or excipient.

    25. The pharmaceutical composition of claim 24, wherein said composition is for use in the treatment of cancer.

    26. Use of an antibody or antigen-binding fragment thereof according to anyone of claims 1 to 18, or of a composition of claim 23 in the manufacture of a medicament for treating a cancer.

    27. Use of an antibody or antigen-binding fragment thereof that competes with an antibody according to anyone of claims 1 to 18 for the binding of CD38 in the manufacture of a medicament for treating cancer.

    28. A method of treating cancer in a subject, comprising administering to the subject an effective amount of the composition of claim 14.

    29. A method of treating cancer in a subject, comprising administering to the subject an effective amount of an antibody or antigen-binding fragment thereof that competes with an antibody according to anyone of claims 1 to 18 for the binding of CD38.

    30. The method of claim 28 or 29, further comprising administering, simultaneously or sequentially in any order, a second agent to the subject.

    31. The method according to anyone of claim 28, 29 or 30 wherein the subject has a solid tumor.

    32. The method according to anyone of claim 28, 29 or 30 wherein the subject has a haematological cancer.

    33. A method of preparing an anti-CD38 antibody comprising providing an antibody according to any one of claims 1 to 18, and subjecting the antibody to affinity maturation, wherein the anti-CD38 antibody produced has a greater affinity to CD38 than the parental antibody.

    34. A method of preparing a pharmaceutical composition comprising providing an antibody prepared according to a method of claim 33 and co-formulating the antibody with at least one or more pharmaceutically acceptable excipients.

    35. A kit comprising the composition of claim 23 in a container.

    Description

    BRIEF DESCRIPTION OF DRAWINGS

    [0108] FIG. 1: flowchart summarizing the screening procedure for identifying aCD38-b-348 as an agonistic anti-CD38 antibody having the one or more properties according to the present invention, in particular those described herein as characteristic of CD38 Modulating Antibody Agents of particular interest: pharmaceutically relevant targeted cell killing (e.g. as measured in ADCC, ADCP, and CDC assays), effects on immune cells (such as Treg, CD8 and CD4 T cells, NK cells, dendritic cells, MDSC, macrophages, and/or monocytes, for measuring properties such as cell viability and/or proliferation, cytokine secretion, and/or activation markers), effects on CD38 enzymatic activities or CD38-mediated signaling, effects on cancer cells expressing (or not) CD38, combinations with other drugs (e.g. antibodies targeting a tumor antigen or other anticancer drugs) and/or antibody sequence and format, for identifying stability issues related to aggregation-prone sequences, presence of glycosylation sites or free Cysteines in variable domain and/or effects (e.g. within a human IgG1 frame, as Fabs, nanobodies, bi/multispecific antibodies, or within non-antibody scaffolds).

    [0109] FIG. 2: relevant protein sequences (A) aCD38-b-348 protein sequences. Each CDR for the heavy (aCD38-b-348-HCDR1 (SEQ ID NO: 1), aCD38-b-348-HCDR2 (SEQ ID NO: 2), and aCD38-b-348-HCDR3 (SEQ ID NO: 3)) and the light (aCD38-b-348-LCDR1 (SEQ ID NO: 5), aCD38-b-348-LCDR2 (SEQ ID NO: 6), and aCD38-b-348-LCDR3 (SEQ ID NO: 7)) chain is indicated separately and, underlined, within the frame sequence of the heavy and light chain antibody as initially identified by the screening procedure (aCD38-b-348-HCDR123 (SEQ ID NO: 4) and aCD38-b-348-LCDR123 (SEQ ID NO: 8), respectively). The DG motif (double underlined) is indicate as hotspot for isomerization and degradation of antibodies (Sydow J et al. 2014) and may be mutated for providing alternative anti-CD38 antibodies having any, and possibly all, binding and functional properties of aCD38-b-348. (B) sequence of human CD38 (Uniprot code P28907, (SEQ ID NO: 9)) in which different boxes identify cytoplasmic domain, transmembrane domain, and, within the extracellular domain, the position of aCD38-b-348 major epitope as preliminarily identified (aCD38-b-ep) compared to the one of Daratumumab epitope (DARA, as identified and disclosed in WO2006099875 being formed by two human CD38 regions, here indicated as DARAep-a and DARAep-b).

    [0110] FIG. 3: characterization of aCD38-b-348 binding to CD38 expressed in PBMCs, using cells of either Cynomolgus Monkey (A) or human origin (B) at increasing antibody concentration and by restricting the analysis to CD8-positive or CD4-positive cells and comparing with either human IgG1 isotype control, Daratumumab (DARA), or in absence of a primary antibody.

    [0111] FIG. 4: functional characterization of aCD38-b-348 compared to Daratumumab (DARA) or negative control antibodies (anti-human CD3 or human IgG1 isotype), in cell-based models independently from the administration of any further tumor targeting antibody. (A) aCD38-b-348 increases the percentage of TCR-mediated CD4 and CD8 T cell proliferation, as indicated in each graph. (IgG1 and each of anti-CD38 antibodies were tested at 10-5-2.5μg/ml; anti-CD3 is tested at 0.1 μg/m). (B) aCD38-b-348 increases NK proliferation and activation in PBMC - MDA-MB-231 co-culture (ratio 100:1). The percentage of proliferating CD56-positive and of CD56-positive, CD137-positive NK cells is indicated in each graph. (C) aCD38-b-348 increases the secretion of selected cytokines by TCR-activated CD4/CD8 T cells (similar pattern in 5 out of 5 donors tested).

    [0112] FIG. 5: functional characterization of aCD38-b-348 compared to DARA with respect to cytotoxicity. (A) Both aCD38-b-348 and DARA induce killing of Regulatory T cells at 1 μg/ml and at 10μg/m by inducing phagocytosis of CD38-positive regulatory T cells. (B) This direct antibody-mediated killing effect is accompanied by antibody-dependent cell-mediated cytotoxicity (ADCC) as in Daratumumab (DARA) but, differently from DARA, not by complement-dependent cytotoxicity (CDC, particularly significant for DARA, as described in the literature). (C) Moreover, targets cell killing, as determined in Daudi cells, is strongly induced by antibody cross-linking when aCD38-b-348 is compared to DARA, whose activity is poorly increased by antibody cross-linking.

    [0113] FIG. 6: functional characterization of aCD38-b-348 (administered at 10 mg/kg) with respect to animal survival in two cancer model based on intra-venous administration of Daudi Cells (A) and Ramos cells (B) over the indicated number of days. The treatment with aCD38-b-348 increases animal survival not only when compared to negative control but also when compared to Daratumumab (DARA).

    [0114] FIG. 7: shows the binding of anti-CD38 antibody aCD38-b-348 as compared to daratumumab to recombinant human CD38 his tagged measured by biolayer interferometry on the Octet Red 96 instrument. 4.2 nM of rhCD38-his was loaded to the Ni NTA biosensor followed by 7 nM of antibody and then let them to dissociate in Kinetics Buffer.

    [0115] FIG. 8: functional characterization of aCD38-b-348 compared to DARA with respect to cytotoxicity. aCD38-b-348 shows ADCP activity as measured using a NFAT report assay.

    [0116] FIG. 9: Functional characterization of aCD38-b-348 compared to Daratumumab and human IgG1 isotype control with respect to enzymatic activity. Tested is the inhibition or activation of CD38 cyclase or NADase (hydrolase) activity in Jurkat cells by aCD38-b-348, and control antibodies. (A) aCD38-b-348 (p=0.34), and DARA decreases the cyclase activity. However the minor inhibition observed for aCD38-b-348 was not statistically significant. (B) aCD38-b-348 and DARA do not decrease NADase activity.

    [0117] FIG. 10: Characterization of aCD38-b-348 (administered at 10 mg/kg) with respect to animal survival in an in vivo solid tumor cancer model based over the indicated number of days. The treatment with aCD38-b-348 increased animal survival not only when compared to negative control but also when compared to Daratumumab (DARA).

    [0118] FIG. 11: functional characterization of aCD38-b-348, compared to Daratumumab (DARA) or negative control antibodies (human IgG1 isotype), in a NFAT signalling luc_ reporter assay in Jurkat cells. The NFAT signalling (measured as Relative luminescence units (RLU)) of the antibody is at least 30% higher than that of daratumumab, when the cells are stimulated with antibody concentrations between 10 and 20 ug/ml and when the RLU of CD3-only stimulation is used as baseline of assay (RLU of CD3-only conditions is subtracted from the other conditions).

    [0119] FIG. 12: shows the binding of aCD38-b-348 (FIG. 12A) as compared to daratumumab (FIG. 12B) to recombinant human CD38 his tagged measured by biolayer interferometry on the Octet Red 96 instrument. 4.2nM of rhCD38-his was loaded to the Ni NTA biosensor followed by varying concentrations of antibody (as shown in the Figures) and then let them to dissociate in Kinetics Buffer.

    [0120] FIG. 13: shows the CDC of aCD38-b-348 compared to Dara and human IgG1 isotype control antibody in Raji cells with 10% complement. aCD38-b-348 exhibits reduced CDC compared to Dara.

    [0121] FIG. 14: Low dose anti-CD38 antibody increases T cell activation in non-human primates. aCD38-b-348 was administered at a dose of 0.03 mg/kg to cynomolgus monkeys and T cell activation was assessed

    [0122] FIG. 15: Relevant heavy and light chain protein sequences of variant aCD38-b-348 antibodies A) aCD38-b-348-m1, B) aCD38-b-348-m2, C) aCD38-b-348-m3 and D) aCD38-b-348-m4. Each CDR for the heavy and the light chain is underlined, within the frame sequence, aCD38-b-348-m1-HCDR123 (SEQ ID NO: 4) and aCD38-b-348-m1-LCDR123 (SEQ ID NO: 20), respectively for aCD38-b-348-m1, aCD38-b-348-m2-HCDR123 (SEQ ID NO: 4) and aCD38-b-348-m2-LCDR123 (SEQ ID NO: 21), respectively for aCD38-b-348-m2, aCD38-b-348-m3-HCDR123 (SEQ ID NO: 4) and aCD38-b-348-m3-LCDR123 (SEQ ID NO: 22), respectively for aCD38-b- 348-m3, and aCD38-b-348-m4-HCDR123 (SEQ ID NO: 4) and aCD38-b-348-m4-LCDR123 (SEQ ID NO: 23), respectively for aCD38-b-348-m4.

    [0123] FIG. 16: Binding of variant sequences to Daudi cells, in comparison with Dara and IgG1 control. Binding to CD38 expression human cell line (Daudi) was examined by adding anti-CD38 primary antibodies at 20 μg/mL followed by a semi-log dilution series (7 points) followed by staining with a secondary antibody. aCD38-b-348 variants show similar binding to Daudi cells as the parental aCD38-b-348 and as DARA.

    [0124] FIG. 17: Functional characterization of aCD38-b-348 and its variant sequences compared to DARA with respect to cytotoxicity. aCD38-b-348 and its variant sequences as well as DARA induce killing of CD38+cell line (Daudi) by antibody-dependent cell-mediated cytotoxicity (ADCC) with no detectable differences in the activity (EC50 or maximum lysis).

    [0125] FIG. 18: Functional characterization of aCD38-b-348 and variant aCD38-b-348-m2 (all administered at 10 mg/kg) with respect to animal survival in two cancer models based on the intra-venous administration of Raji Cells (A) and Ramos cells (B) over the indicated number of days. The treatment with aCD38-b-348 increases animal survival when compared to negative control and when compared to DARA in both models. The treatment with the variant aCD38-b-348-m2 increases animal survival when compared to negative control in both models.

    [0126] FIG. 19: SPR based analysis of purified antibodies (IgG1) to rhCD38 his tagged on the Biacore 2000. A) aCD38-b-348, B) aCD38-b-348-m1, C) aCD38-b-348-m2, D) aCD38-b-348m3 and E) aCD38-b-348-m4.

    [0127] FIG. 20: Degranulation of unactivated or IL-2 pre-activated human NK cells induced by aCD38-b-348 compared to hIgG1 isotype, daratumumab and controls.

    [0128] FIG. 21: IFNγ production of NK cells in the presence or absence of a tumor target (MDA-MB-231 cells) induced by aCD38-b-348 compared to hIgG1 isotype and daratumumab.

    [0129] FIG. 22: NK cell proliferation of human NK cells in the presence of MDA-MB-231 tumor cells induced by aCD38-b-348 compared to hIgG1 isotype and daratumumab. A) Antibodies tested at 10 μg /ml. B) dose titration of antibodies from 0.4 μg/ml to 10 μg/ml tested.

    [0130] FIG. 23: Competition Assays in the Octet. Binding of aCD38-b-348 to the immobilized rhCD38 is followed by either first antibody again (Daratumumab - as control) or a second Ab (aCD38-b-348). Non-competitors Antibodies will bind to CD38 in the presence of the other antibody (as shown) while antibodies binding the same epitope will compete, and no additional binding will be observed.

    DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

    [0131] Below are provided certain definitions of terms, technical means, and embodiments used herein, many or most of which confirm common understanding of those skilled in the art.

    [0132] Administration: As used herein, the term “administration” refers to the administration of a composition to a subject. Administration to an animal subject (e.g., to a human) may be by any appropriate route. For example, in some embodiments, administration may be bronchial (including by bronchial instillation), buccal, enteral, intra-arterial, intra-dermal, intra-gastric, intra-medullary, intra-muscular, intra-nasal, intra-peritoneal, intra-thecal, intra-venous, intra-ventricular, within a specific organ or tissue (e. g. intra-hepatic, intra-tumoral, peri-tumoral, etc), mucosal, nasal, oral, rectal, subcutaneous, sublingual, topical, tracheal (including by intra-tracheal instillation), transdermal, vaginal and vitreal. The administration may involve intermittent dosing. Alternatively, administration may involve continuous dosing (e.g., perfusion) for at least a selected period of time. As is known in the art, antibody therapy is commonly administered parenterally, e.g. by intravenous, subcutaneous, or intratumoral injection (e.g., particularly when high doses within a tumor are desired).

    [0133] Agent: The term “agent” as used herein may refer to a compound or entity of any chemical class including, for example, polypeptides, nucleic acids, saccharides, small molecules, metals, or combinations thereof. Specific embodiments of agents that may be utilized in accordance with the present invention include small molecules, drugs, hormones, antibodies, antibody fragments, aptamers, nucleic acids (e.g., siRNAs, shRNAs, antisense oligonucleotides, ribozymes), peptides, peptide mimetics, etc. An agent may be or comprise a polymer.

    [0134] Antibody: As used herein, the term “antibody” refers to a polypeptide that includes canonical immunoglobulin sequence elements sufficient to confer specific binding to a particular target antigen, such as CD38, human CD38 in particular, and human CD38 extracellular. As is known in the art, intact antibodies as produced in nature are approximately 150 kD tetrameric agents comprised of two identical heavy chain polypeptides (about 50 kD each) and two identical light chain polypeptides (about 25 kD each) that associate with each other into what is commonly referred to as a “Y-shaped” structure. Each heavy chain is comprised of at least four domains (each about 110 amino acids long), an amino-terminal variable (VH) domain (located at the tips of the Y structure), followed by three constant domains: CH1, CH2, and the carboxy-terminal CH3 (located at the base of the Y's stem). A short region, known as the “switch”, connects the heavy chain variable and constant regions. The “hinge” connects CH2 and CH3 domains to the rest of the antibody. Two disulfide bonds in this hinge region connect the two heavy chain polypeptides to one another in an intact antibody. Each light chain is comprised of two domains—an amino-terminal variable (VL) domain, followed by a carboxy-terminal constant (CL) domain, separated from one another by another “switch”. Intact antibody tetramers are comprised of two heavy chain-light chain dimers in which the heavy and light chains are linked to one another by a single disulfide bond; two other disulfide bonds connect the heavy chain hinge regions to one another, so that the dimers are connected to one another and the tetramer is formed. Naturally produced antibodies are also glycosylated, typically on the CH2 domain, and each domain has a structure characterized by an “immunoglobulin fold” formed from two beta sheets (e.g., 3-, 4-, or 5-stranded sheets) packed against each other in a compressed antiparallel beta barrel. Each variable domain contains three hypervariable loops known as “complement determining regions” (CDR1, CDR2, and CDR3; as understood in the art, for example determined according to Kabat numbering scheme) and four somewhat invariant “framework” regions (FR1, FR2, FR3, and FR4). When natural antibodies fold, the FR regions form the beta sheets that provide the structural framework for the domains, and the CDR loop regions from both the heavy and light chains are brought together in three-dimensional space so that they create a single hypervariable antigen-binding site located at the tip of the Y structure. The Fc region of naturally-occurring antibodies binds to elements of the complement system, and also to receptors on effector cells, including for example effector cells that mediate cytotoxicity. As is known in the art, affinity and/or other binding attributes of Fc regions for Fc receptors can be modulated through glycosylation or other modification that can improve the developability of the antibody (Jarasch A et al., 2015).

    [0135] In some embodiments, antibodies produced and/or utilized in accordance with the present invention include glycosylated Fc domains, including Fc domains with modified or engineered such glycosylation. For purposes of the present invention, in certain embodiments, any polypeptide or complex of polypeptides that includes sufficient immunoglobulin domain sequences as found in natural antibodies can be referred to and/or used as an “antibody”, whether such polypeptide is naturally produced (e.g., generated by an organism reacting to an antigen), or produced by recombinant engineering, chemical synthesis, or other artificial system or methodology. In some embodiments, an antibody is polyclonal or oligoclonal, that is generated as a panel of antibodies, each associated to a single antibody sequence and binding a more or less distinct epitopes within an antigen (such as different epitopes within human CD38 extracellular domain that are associated to different reference anti-CD38 antibodies).

    [0136] Polyclonal or oligoclonal antibodies can be provided in a single preparation for medical uses as described in the literature (Kearns JD et al., 2015). In some embodiments, an antibody is monoclonal. In some embodiments, an antibody has constant region sequences that are characteristic of mouse, rabbit, primate, or human antibodies. In some embodiments, antibody sequence elements are humanized, primatized, chimeric, etc, as is known in the art. Moreover, the term “antibody” as used herein, can refer in appropriate embodiments (unless otherwise stated or clear from context) to any of the art-known or developed constructs or formats for utilizing antibody structural and functional features in alternative presentation, for instance as antigen-binding fragments as defined below. For example, an antibody utilized in accordance with the present invention is in a format selected from, but not limited to, intact IgG, IgE and IgM, bi- or multi- specific antibodies (e.g., Zybodies®, etc), single chain variable domains (scFv), polypeptide-Fc fusions, Fabs, cameloid antibodies, heavy-chain shark antibody (IgNAR), masked antibodies (e.g., Probodies®), or fusion proteins with polypeptides that allow expression and exposure on the cell surface (as scFv within constructs for obtaining artificial T cell receptors that are used to graft the specificity of a monoclonal antibody onto a T cell). In some embodiments, an antibody may lack a covalent modification (e.g., attachment of a glycan) that it would have if produced naturally. Alternatively, an antibody may contain a covalent modification (e.g., attachment of a glycan, a payload [e.g., a detectable moiety, a therapeutic moiety, a catalytic moiety, etc.], or other pendant group [e.g., poly-ethylene glycol, etc.]).

    [0137] Antigen: The term “antigen”, as used herein, refers to an agent that elicits an immune response and/or that binds to a T cell receptor (e.g., when presented by an MHC molecule) and/or B cell receptor. An antigen that elicits a humoral response involve the production of antigen-specific antibodies or, as shown in the Examples for CD38 extracellular domain, can be used for screening antibody libraries and identifying candidate antibody sequences to be further characterized.

    [0138] Antigen-binding Fragment: As used herein, the term “Antigen-binding Fragment” encompasses agents that include or comprise one or more portions of an antibody as described herein sufficient to confer on the antigen-binding fragment and ability to specifically bind to the Antigen targeted by the antibody. For example, in some embodiments, the term encompasses any polypeptide or polypeptide complex that includes immunoglobulin structural elements sufficient to confer specific binding. Exemplary antigen-binding fragments include, but are not limited to Small Modular ImmunoPharmaceuticals (“SMIPs™ ”), single chain antibodies, cameloid antibodies, single domain antibodies (e.g., shark single domain antibodies), single chain or Tandem diabodies (TandAb®), VHHs, Anticalins®, Nanobodies®, minibodies, BiTE®s, ankyrin repeat proteins or DARPINs®, Avimers®, a DART, a TCR-like antibody, Adnectins®, Affilins®, Trans-bodies®, Affibodies®, a TrimerX®, MicroProteins, Centyrins®, CoVX bodies, BiCyclic peptides, Kunitz domain derived antibody constructs, or any other antibody fragments so long as they exhibit the desired biological activity. In some embodiments, the term encompasses other protein structures such as stapled peptides, antibody-like binding peptidomimetics, antibody-like binding scaffold proteins, monobodies, and/or other non-antibody proteins scaffold, for example as reviewed in the literature (Vazquez-Lombardi R et al., 2015). In some embodiments, an antigen-binding fragment is or comprises a polypeptide whose amino acid sequence includes one or more structural elements recognized by those skilled in the art as a complementarity determining region (CDR). In some embodiments an antigen-binding fragment is or comprises a polypeptide whose amino acid sequence includes at least one reference CDR (e.g., at least one heavy chain CDR and/or at least one light chain CDR) that is substantially identical to one found in an anti-CD38 antibody as described herein (e.g., in an aCD38-b-348 amino acid sequence element), and in particular at least one heavy chain CDR, such as an HCDR3 (e.g., an aCD38-b-348-HCDR3 sequence). In some embodiments an antigen-binding fragment is or comprises a polypeptide whose amino acid sequence includes at least one CDR (e.g., at least one heavy chain CDR and/or at least one light chain CDR) that is either identical in sequence or contains a small number (e.g., 1, 2, 3, or 4) more amino acid alterations (e.g., substitutions, additions, or deletions; in many cases, substitutions) relative to such a reference CDR, while maintaining binding to the target of the antibody (e.g., aCD38-b-348) from which the reference CDR was derived. In some embodiments, an antigen-binding fragment is or comprises a polypeptide or complex thereof that includes all three CDRs (or, in some embodiments, sequences substantially identical thereto) from a heavy or light chain of a reference antibody (e.g., from aCD38-b-348); in some embodiments, an antigen-binding fragment is or comprises a polypeptide or complex thereof that includes all six CDRs (or, in some embodiments, sequences substantially identical thereto) from a reference antibody (e.g., from aCD38-b-348). In some embodiments, an antigen-binding fragment is or comprises a polypeptide or complex thereof that includes the heavy and/or light chain variable domains (or, in some embodiments, sequences substantially identical thereto) of a reference antibody (e.g., of aCD38-b-348). In some embodiments, the term “antigen-binding fragment” encompasses non-peptide and non-protein structures, such as nucleic acid aptamers, for example, RNA aptamers and DNA aptamers. An aptamer is an oligonucleotide (e.g., DNA, RNA, or an analog or derivative thereof) that binds to a particular target, such as a polypeptide. Aptamers are short synthetic single-stranded oligonucleotides that specifically bind to various molecular targets such as small molecules, proteins, nucleic acids, and even cells and tissues. These small nucleic acid molecules can form secondary and tertiary structures capable of specifically binding proteins or other cellular targets, and are essentially a chemical equivalent of antibodies. Aptamers are highly specific, relatively small in size, and non-immunogenic. Aptamers are generally selected from a biopanning method known as SELEX (Systematic Evolution of Ligands by Exponential enrichment) (See for example Ellington et al. Nature. 1990; 346(6287): 818-822; Tuerk et al., Science. 1990; 249(4968):505-510; Ni et al., Curr Med Che 2011; 18(27):4206-14). Methods of generating an apatmer for any given target are well known in the art. Peptide aptamers including affimers are also encompassed. An affimer is a small, highly stable protein engineered to display peptide loops which provide a high affinity binding surface for a specific target protein. It is a protein of low molecular weight, 12-14 kDa, derived from the cysteine protease inhibitor family of cystatins. Affimer proteins are composed of a scaffold, which is a stable protein based on the cystatin protein fold. They display two peptide loops and an N-terminal sequence that can be randomized to bind different target proteins with high affinity and specificity similar to antibodies. Stabilization of the peptide upon the protein scaffold constrains the possible conformations which the peptide may take, thus increasing the binding affinity and specificity compared to libraries of free peptides.

    [0139] Percent (%) sequence identity: Percent (%) “sequence identity” between two sequences can be determined using those methods known in the art. Sequence identity with respect to a peptide, polypeptide or antibody sequence can be defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the specific peptide or polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, including gapped BLAST, and BLASTp (for proteins), (Altschul SF et al (1997)), or FASTA., using the default parameters.

    [0140] Biological Sample. As used herein, the terms “biological sample” or “sample” typically refers to a sample obtained or derived from a biological source (e.g., a tissue or organism or cell culture) of interest, as described herein. A source of interest may be an organism, such as an animal or human. The biological sample may comprise biological tissue or fluid.

    [0141] Cancer. The terms “cancer”, “malignancy”, “neoplasm”, “tumor”, “tumour”, and “carcinoma”, are used interchangeably herein to refer to cells that exhibit relatively abnormal, uncontrolled, and/or autonomous growth, so that they exhibit an aberrant growth phenotype characterized by a significant loss of control of cell proliferation. In general, cells of interest for detection or treatment in the present application include precancerous (e.g., benign), malignant, pre-metastatic, metastatic, and non-metastatic cells. The teachings of the present disclosure may be relevant to any and all cancers. To give but a few, non-limiting examples, in some embodiments, teachings of the present disclosure are applied to one or more cancers such as, for example, hematopoietic cancers including leukemias, lymphomas (Hodgkins and non-Hodgkins), myelomas and myeloproliferative disorders; sarcomas, melanomas, adenomas, carcinomas of solid tissue, squamous cell carcinomas of the mouth, throat, larynx, and lung, liver cancer, genitourinary cancers such as prostate, cervical, bladder, uterine, and endometrial cancer and renal cell carcinomas, bone cancer, pancreatic cancer, skin cancer, cutaneous or intraocular melanoma, cancer of the endocrine system, cancer of the thyroid gland, cancer of the parathyroid gland, head and neck cancers, breast cancer, gastro-intestinal cancers and nervous system cancers, benign lesions such as papillomas, and the like. The antibodies of the invention can be used in the treatment of CD38+expressing tumours.

    [0142] CD38 Modulating Antibody Agent The term “CD38 Modulating Antibody Agent” is used herein to refer to those CD38 Modulating Antibody Agents (e.g., anti-CD38 antibodies) that demonstrate particular properties as described herein. In many embodiments, desirable CD38 Modulating Antibody Agents as described herein are characterized in that they stimulate immune effector cells and/or modify immune cells function and are cytotoxic towards or induce phagocytosis of CD38 expressing cells (e.g. expressing high levels of CD38) such as immune suppressive cells or tumour cells (e.g., in each case, that express CD38 on their surfaces). In some embodiments, a CD38 Modulating Antibody Agent is characterized by an activity (e.g., level and/or type) reasonably comparable to that of aCD38-b-348 with respect to immune cells (e.g., when contacted with immune cells, and particularly with immune cells that express CD38) and tumour cells. In some embodiments, a relevant activity is or comprises ADCP, ADCC in absence of CDC, direct killing, depletion of certain CD38-expressing cells (e.g., high-expressing cells), effector immune cell activation, promotion of T cell, B cell or NK cell expansion, modulation of immune cells activity (e.g. repolarization of suppressive macrophages into inflammatory macrophages), skewing of T cell repertoire, etc., and combinations thereof. In some embodiments, CD38 Modulating Antibody Agents are entities or moieties whose presence or level correlates with level and/or activity of CD38, and/or with one or more features or results characteristic of CD38 activity. In some embodiments, an increased level and/or activity is assessed or determined relative to that observed under otherwise comparable conditions in absence of the entity(ies) or moiety(ies). Alternatively or additionally, in some embodiments, an increased level and/or activity is comparable to or greater than that observed under comparable conditions when a reference CD38 Modulating Antibody Agents (e.g., an appropriate reference anti-CD38 antibody, which in many embodiments is a CD38 agonist antibody, such as IB4) is present. In many embodiments, a CD38 Modulating Antibody Agent for use in accordance with the present disclosure is or comprises an entity or moiety that binds, directly or indirectly, to CD38, typically to its extracellular domain. In some embodiments, a CD38 Modulating Antibody Agent is, comprises, or competes for binding to CD38 with an anti-CD38 antibody as exemplified herein, an antigen-binding fragment (e.g., comprising one or more CDRs, all heavy chain CDRs, all light chain CDRs, all CDRs, a heavy chain variable region, a light chain variable region, or both heavy and light chain variable regions) thereof, an affinity matured variant thereof (or an antigen-binding fragment thereof), or any alternative format (e.g., chimeric, humanized, multispecific, alternate isotype, etc) of any of the foregoing. Alternatively or additionally, in some embodiments, a CD38 Modulating Antibody Agent as described herein may be characterized by one or more features that may be features that are advantageous for screening, manufacturing, (pre-)clinical testing, and/or for identifying relevant epitope within human CD38, such as the sequence identified as aCD38-b-ep), and/or for formulation, administration, and/or efficacy in particular contexts (e.g., for cancer therapy), as disclosed herein.

    [0143] Combination Therapy: As used herein, the term “combination therapy” refers to those situations in which a subject is simultaneously exposed to two or more therapeutic regimens (e.g., two or more therapeutic agents). In some embodiments, two or more agents may be administered simultaneously. Alternatively, such agents may be administered sequentially; otherwise, such agents are administered in overlapping dosing regimens.

    [0144] Comparable: As used herein, the term “comparable” refers to two or more agents, entities, situations, effects, sets of conditions, etc., that may not be identical to one another but that are sufficiently similar to permit comparison (e.g., by level and/or activity) there between so that conclusions may reasonably be drawn based on differences or similarities observed. Such comparable sets of conditions, effects, circumstances, individuals, or populations are characterized by a plurality of substantially identical features and one or a small number of varied features. Those of ordinary skill in the art will understand, in context, what degree of identity is required in any given circumstance for two or more such agents, entities, situations, sets of conditions, effects, or populations, etc. to be considered comparable.

    [0145] Comprising: A composition or method described herein as “comprising” one or more named elements or steps is open-ended, meaning that the named elements or steps are essential, but other elements or steps may be added within the scope of the composition or method. It is also understood that any composition or method described as “comprising” (or which “comprises”) one or more named elements or steps also describes the corresponding, more limited composition or method “consisting essentially of” (or which “consists essentially of”) the same named elements or steps, meaning that the composition or method includes the named essential elements or steps and may also include additional elements or steps that do not materially affect the basic and novel characteristic(s) of the composition or method.

    [0146] Daratumumab: As used herein, the term “daratumumab” includes an antibody having, VH and VL sequences as published in WO2006/099875 and being a human IgG1 monoclonal antibody. For example having variable heavy and light chain sequences comprising the sequences as provided below:

    TABLE-US-00011 Heavy Chain: (SEQ ID NO: 24) EVQLLESGGGLVQPGGSLRLSCAVSGFTFNSFAMSWVRQAPGKGLEWVS AISGSGGGTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYFCAK DKILWFGEPVFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAAL GCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS SLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKT KPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISK AKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQP ENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHY TQKSLSLSPGK Light Chain (SEQ ID NO: 25) EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIY DASNRATGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQRSNWPPTF GQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQ WKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEV THQGLSSPVTKSFNRGEC

    [0147] Dosage Form: As used herein, the term “dosage form” refers to a physically discrete unit of an active agent (e.g., a therapeutic or diagnostic agent) for administration to a subject. Each unit contains a predetermined quantity of active agent. In some embodiments, such quantity is a unit dosage amount (or a whole fraction thereof) appropriate for administration in accordance with a dosing regimen that has been determined to correlate with a desired or beneficial outcome when administered to a relevant population (i.e., with a therapeutic dosing regimen). Those of ordinary skill in the art appreciate that the total amount of a therapeutic composition or agent administered to a particular subject is determined by one or more attending physicians and may involve administration of multiple dosage forms.

    [0148] Dosing Regimen: As used herein, the term “dosing regimen” refers to a set of unit doses (typically more than one) that are administered individually to a subject, typically separated by periods of time. In some embodiments, a given therapeutic agent has a recommended dosing regimen, which may involve one or more doses. In some embodiments, a dosing regimen comprises a plurality of doses each of which are separated from one another by a time period of the same length. Alternatively, a dosing regimen comprises a plurality of doses and at least two different time periods separating individual doses. In some embodiments, all doses within a dosing regimen are of the same unit dose amount. Alternatively, different doses within a dosing regimen are of different amounts. In some embodiments, a dosing regimen comprises a first dose in a first dose amount, followed by one or more additional doses in a second dose amount different from the first dose amount. A dosing regimen may comprise a first dose in a first dose amount, followed by one or more additional doses in a second dose amount same as the first dose amount. In some embodiments, a dosing regimen is correlated with a desired or beneficial outcome when administered across a relevant population (i.e., is a therapeutic dosing regimen).

    [0149] Epitope: As used herein, the term “epitope” refers to a portion of an antigen that is bound by an antibody or antigen-binding fragment. In some embodiments, where the antigen is a polypeptide, an epitope is conformational in that it is comprised of portions of an antigen that are not covalently contiguous in the antigen but that are near to one another in three-dimensional space when the antigen is in a relevant conformation. For example, for CD38, conformational epitopes are those comprised of amino acid residues that are not contiguous in CD38 extracellular domain; linear epitopes are those comprised of amino acid residues that are contiguous in CD38 extracellular domain. In some embodiments, epitopes utilized in accordance with the present invention are provided by means of reference to those bound by CD38 Modulating Antibody Agents provided herein (e.g., by aCD38-b-348 and defined as aCD38-b-ep). Means for determining the exact sequence and/or particularly amino acid residues of the epitope for aCD38-b-348 are known in the literature and in the Examples, including competition with peptides, from antigen sequences, binding to CD38 sequence from different species, truncated, and/or mutagenized (e.g. by alanine scanning or other site-directed mutagenesis), phage display-based screening, or (co-) crystallography techniques.

    [0150] Patient: As used herein, the term “patient” or “subject” refers to any organism to which a provided composition is or may be administered, e.g., for experimental, diagnostic, prophylactic, cosmetic, and/or therapeutic purposes. Typical patients include animals (e.g., mammals such as mice, rats, rabbits, non-human primates, and/or humans). In some embodiments, a patient is a human. In some embodiments, a patient is suffering from or susceptible to one or more disorders or conditions. A patient may display one or more symptoms of a disorder or condition, or may have been diagnosed with one or more disorders or conditions (such as cancer, or presence of one or more tumors). In some embodiments, the patient is receiving or has received certain therapy to diagnose and/or to treat such disease, disorder, or condition.

    [0151] Pharmaceutically Acceptable: As used herein, the term “pharmaceutically acceptable” applied to the carrier, diluent, or excipient used to formulate a composition as disclosed herein means that the carrier, diluent, or excipient must be compatible with the other ingredients of the composition and not deleterious to the recipient thereof.

    [0152] Pharmaceutical Composition: As used herein, the term “pharmaceutical composition” refers to a composition in which an active agent is formulated together with one or more pharmaceutically acceptable carriers. In some embodiments, active agent is present in unit dose amount appropriate for administration in a therapeutic regimen that shows a statistically significant probability of achieving a predetermined therapeutic effect when administered to a relevant population. A pharmaceutical compositions may be formulated for administration in solid or liquid form, including those adapted for the following: oral administration, for example, drenches (aqueous or non-aqueous solutions or suspensions), tablets, e.g., those targeted for buccal, sublingual, and systemic absorption, boluses, powders, granules, pastes for application to the tongue; parenteral administration, for example, by subcutaneous, intramuscular, intravenous, intratumoral, or epidural injection as a sterile solution or suspension, or sustained-release formulation; topical application, for example, as a cream, ointment, or a controlled-release patch or spray applied to skin, lungs, or oral cavity; intravaginally, intrarectally, sublingually, ocularly, transdermally, nasally, pulmonary, and to other mucosal surfaces.

    [0153] Solid Tumor. As used herein, the term “solid tumor” refers to an abnormal mass of tissue that usually does not contain cysts or liquid areas. Solid tumors may be benign or malignant. Different types of solid tumors are named for the type of cells that form them. Examples of solid tumors are sarcomas (including cancers arising from transformed cells of mesenchymal origin in tissues such as cancellous bone, cartilage, fat, muscle, vascular, hematopoietic, or fibrous connective tissues), carcinomas (including tumors arising from epithelial cells), melanomas, lymphomas, mesothelioma, neuroblastoma, retinoblastoma, etc. Cancers involving solid tumors include, without limitations, brain cancer, lung cancer, stomach cancer, duodenal cancer, esophagus cancer, breast cancer, colon and rectal cancer, renal cancer, bladder cancer, kidney cancer, pancreatic cancer, prostate cancer, ovarian cancer, melanoma, mouth cancer, sarcoma, eye cancer, thyroid cancer, urethral cancer, vaginal cancer, neck cancer, lymphoma, and the like.

    [0154] Therapeutically Effective Amount: As used herein, the term “therapeutically effective amount” means an amount (e.g., of an agent or of a pharmaceutical composition) that is sufficient, when administered to a population suffering from or susceptible to a disease and/or condition in accordance with a therapeutic dosing regimen, to treat such disease and/or condition. A therapeutically effective amount is one that reduces the incidence and/or severity of, stabilizes, and/or delays onset of, one or more symptoms of the disease, disorder, and/or condition. Those of ordinary skill in the art will appreciate that a “therapeutically effective amount” does not in fact require successful treatment be achieved in a particular subject.

    [0155] Treatment: As used herein, the term “treatment” (also “treat” or “treating”) refers to any administration of a substance (e.g., provided CD38 Modulating Antibody Agent, as exemplified by aCD38-b-348, or any other agent) that partially or completely alleviates, ameliorates, relives, inhibits, delays onset of, reduces severity of, and/or reduces incidence of one or more symptoms. In some embodiments, treatment may involve the direct administration of a CD38 Modulating Antibody Agent such as aCD38-b-348 (for example, as an injectable, aqueous composition, optionally comprising a pharmaceutically acceptable carrier, excipient and/or adjuvant, for use for intravenous, intratumoral or peritumoral injection) or the administration using a regimen comprising obtaining cells from the subject (e.g. from the blood, a tissue, or a tumor, with or without a selection on the basis of presence, or absence, of the expression of a marker), contacting said cells with a CD38 Modulating Antibody Agent such as aCD38-b-348 ex vivo, and administering such cells to the subject (with or without a selection on the basis of presence, or absence, of the expression of a marker).

    [0156] Dosing and Administration. Pharmaceutical compositions comprising a CD38 Modulating Antibody Agent as described herein (.e.g, an anti-CD38 or antigen-binding fragment thereof, for example comprising the aCD38-b-348-HCDR3 amino acid sequence) for use in accordance with the present invention may be prepared for storage and/or delivery using any of a variety of techniques and/or technologies known and/or available to those skilled in the art. In some embodiments, a provided CD38 Modulating Antibody Agent is administered according to a dosing regimen approved by a regulatory authority such as the United States Food and Drug Administration (FDA) and/or the European Medicines Agency (EMEA), e.g., for the relevant indication. In some embodiments, a provided CD38 Modulating Antibody Agent is administered in combination with one or more other agents or therapies, which may themselves be administered according to a dosing regimen approved by a regulatory authority such as the United States Food and Drug Administration (FDA) and/or the European Medicines Agency (EMEA), e.g., for the relevant indication. In some embodiments however, use of a provided CD38 Modulating Antibody Agent may permit reduced dosing (e.g., lower amount of active in one or more doses, smaller number of doses, and/or reduced frequency of doses) of an approved agent or therapy used in combination with the CD38 Modulating Antibody Agent therapy. In some embodiments, dosing and/or administration may be adapted to other drugs that also administered, the patient status, and/or the format of CD38 Modulating Antibody Agent (e.g. modified as an immunoconjugate, a nanobody, or a bispecific antibody).

    [0157] Moreover, in some embodiments, it may be desirable to tailor dosing regimens, and particularly to design sequential dosing regimens, based on timing and/or threshold expression levels of CD38, whether for particular cell types, particular tumors or types thereof, or particular patient populations (e.g., carrying genetic markers). In some such embodiments, therapeutic dosing regimens may be combined with or adjusted in light of detection methods that assess expression of one or more inducible markers or other criteria prior to and/or during therapy.

    [0158] In some embodiments, dosing and administration according to the present invention utilizes active agent having a desired degree of purity combined with one or more physiologically acceptable carriers, excipients or stabilizers in any or variety of forms. These include, for example, liquid, semi-solid and solid dosage forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, tablets, pills, powders, liposomes and suppositories. A preferred form may depend on the intended mode of administration and/or therapeutic application, typically in the form of injectable or infusible solutions, such as compositions similar to those used for treating of human subjects with antibodies.

    [0159] In some embodiments, ingredient(s) can be prepared with carriers that protect the agent(s) against rapid release and/or degradation, such as a controlled release formulation, including implants, transdermal patches, and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as polyanhydrides, polyglycolic acid, polyorthoesters, and polylactic acid. In general, each active agent is formulated, dosed, and administered in therapeutically effective amount using pharmaceutical compositions and dosing regimens that are consistently with good medical practice and appropriate for the relevant agent(s) (e.g., for agents such as antibodies). Pharmaceutical compositions containing active agents can be administered by any appropriate method known in the art, including, without limitation, oral, mucosal, by-inhalation, topical, buccal, nasal, rectal, or parenteral (e.g. intravenous, infusion, intratumoral, intranodal, subcutaneous, intraperitoneal, intramuscular, intradermal, transdermal, or other kinds of administration involving physical breaching of a tissue of a subject and administration of the pharmaceutical composition through such breach).

    [0160] In some embodiments, a dosing regimen for a particular active agent may involve intermittent or continuous (e.g., by perfusion or slow release system) administration, for example to achieve a particular desired pharmacokinetic profile or other pattern of exposure in one or more tissues or fluids of interest in the subject. In some embodiments, different agents administered in combination may be administered via different routes of delivery and/or according to different schedules. Alternatively, or additionally, in some embodiments, one or more doses of a first active agent is administered substantially simultaneously with, and in some embodiments via a common route and/or as part of a single composition with, one or more other active agents.

    [0161] Factors to be considered when optimizing routes and/or dosing schedule for a given therapeutic regimen may include, for example, the particular cancer being treated (e.g., type, stage, location, etc.), the clinical condition of a subject (e.g., age, overall health, weight, etc.), the site of delivery of the agent, the nature of the agent (e.g. an antibody or other protein-based compound), the mode and/or route of administration of the agent, the presence or absence of combination therapy, and other factors known to medical practitioners.

    [0162] Those skilled in the art will appreciate, for example, that a specific route of delivery may impact dose amount and/or required dose amount may impact route of delivery. For example, where particularly high concentrations of an agent within a particular site or location (e.g., within a tissue or organ) are of interest, focused delivery (e.g., intratumoral delivery) may be desired and/or useful. In some embodiments, one or more features of a particular pharmaceutical composition and/or of a utilized dosing regimen may be modified over time (e.g., increasing or decreasing amount of active in any individual dose, increasing or decreasing time intervals between doses, etc.), for example in order to optimize a desired therapeutic effect or response (e.g., a therapeutic or biological response that is related to the functional features of a CD38 Modulating Antibody Agent as described herein). In general, type, amount, and frequency of dosing of active agents in accordance with the present invention in governed by safety and efficacy requirements that apply when relevant agent(s) is/are administered to a mammal, preferably a human. In general, such features of dosing are selected to provide a particular, and typically detectable, therapeutic response as compared with what is observed absent therapy. In context of the present invention, an exemplary desirable therapeutic response may involve, but is not limited to, inhibition of and/or decreased tumor growth, tumor size, metastasis, one or more of the symptoms and side effects that are associated with the tumor, as well as increased apoptosis of cancer cells, therapeutically relevant decrease or increase of one or more cell marker or circulating markers and the like. Such criteria can be readily assessed by any of a variety of immunological, cytological, and other methods that are disclosed in the literature. For example, the therapeutically effective amount of CD38 Modulating Antibody Agents, alone or in combination with a further agent, can be determined as being sufficient to enhance killing of cancer cells as described in the Examples.

    [0163] A therapeutically effective amount of a CD38 Modulating Antibody Agent as active agent or composition comprising such agent can be readily determined using techniques available in the art including, for example, considering one or more factors such as the disease or condition being treated, the stage of the disease, the age and health and physical condition of the mammal being treated, the severity of the disease, the particular compound being administered, and the like.

    [0164] In some embodiments, therapeutically effective amount is an effective dose (and/or a unit dose) of an active agent that may be at least about 0.01 μg/kg body weight, at least about 0.05 μg/kg body weight; at least about 0.1 μg/kg body weight, at least about 1 μg/kg body weight, at least about 5 μg/kg body weight, at least about 10 μg/kg body weight, or more (e.g. about 100 μg/kg body weight). It will be understood by one of skill in the art that in some embodiments such guidelines may be adjusted for the molecular weight of the active agent. The dosage may also be varied for route of administration, the cycle of treatment, or consequently to dose escalation protocol that can be used to determine the maximum tolerated dose and dose limiting toxicity (if any) in connection to the administration of the isolated antibody or antigen-binding fragment thereof comprising the aCD38-b-348-HCDR3 amino acid sequence at increasing doses.

    [0165] Therapeutic compositions typically should be sterile and stable under the conditions of manufacture and storage. The composition can be formulated as a solution, microemulsion, dispersion, liposome, or other ordered structure suitable to high drug concentration. Sterile injectable solutions can be prepared by incorporating the antibody in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle that contains a basic dispersion medium and other required ingredients from those enumerated above. In the case of powders for preparing sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze drying that yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile filtered solution. The proper fluidity of a solution can be maintained, for example, by using a coating, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prolonged absorption of injectable compositions can be brought about by including in the composition an agent that delays absorption, for example, monostearate salts and gelatin.

    [0166] The formulation of each agent should desirably be sterile, as can be accomplished by filtration through sterile filtration membranes, and then packaged, or sold in a form suitable for bolus administration or for continuous administration. Injectable formulations may be prepared, packaged, or sold in unit dosage form, such as in ampules or in multi dose containers containing a preservative. Formulations for parenteral administration include, but are not limited to, suspensions, solutions, emulsions in oily or aqueous vehicles, pastes, and implantable sustained-release or biodegradable formulations as discussed herein. Sterile injectable formulations may be prepared using a non-toxic parenterally acceptable diluent or solvent, such as water or 1,3 butanediol. Other parentally-administrable formulations which are useful include those which comprise the active ingredient in microcrystalline form, in a liposomal preparation, or as a component of biodegradable polymer systems. Compositions for sustained release or implantation may comprise pharmaceutically acceptable polymeric or hydrophobic materials such as an emulsion, an ion exchange resin, a sparingly soluble polymer or salt.

    [0167] Each pharmaceutical composition for use in accordance with the present invention may include pharmaceutically acceptable dispersing agents, wetting agents, suspending agents, isotonic agents, coatings, antibacterial and antifungal agents, carriers, excipients, salts, or stabilizers are non-toxic to the subjects at the dosages and concentrations employed. A non-exhaustive list of such additional pharmaceutically acceptable compounds includes buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; salts containing pharmacologically acceptable anions (such as acetate, benzoate, bicarbonate, bisulfate, isothionate, lactate, lactobionate, laurate, malate, maleate, salicylate, stearate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, thiethiodode, and valerate salts); preservatives (such as octadecyidimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; sodium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g., Zn-protein complexes); and/or non-ionic surfactants such as TWEEN™, PLURONICS™, or polyethylene glycol (PEG).

    [0168] In some embodiments, where two or more active agents are utilized in accordance with the present invention, such agents can be administered simultaneously or sequentially. In some embodiments, administration of one agent is specifically timed relative to administration of another agent. In some embodiments, desired relative dosing regimens for agents administered in combination may be assessed or determined empirically, for example using ex vivo, in vivo and/or in vitro models; in some embodiments, such assessment or empirical determination is made in vivo, in a particular patient or patient population (e.g., so that a correlation is made).

    [0169] In some embodiments, one or more active agents utilized in practice of the present invention is administered according to an intermittent dosing regimen comprising at least two cycles. Where two or more agents are administered in combination, and each by such an intermittent, cycling, regimen, individual doses of different agents may be interdigitated with one another. In some embodiments, one or more doses of the second agent is administered a period of time after a dose of a CD38 Modulating Antibody Agent as described herein. In some embodiments, each dose of the second agent is administered a period of time after a dose of CD38 Modulating Antibody Agent as described herein. In some embodiments, a CD38 Modulating Antibody Agent as described herein can be also administered in regimens that involve not only subsequent administration by the same route but also by alternating administration routes such as by sub-cutaneous (or intramuscular) administration and intra-tumoral administration, within one or more cycles of treatments over one, two, four or more weeks, repeating such cycle with the same regimen (or by extending the interval between administrations), depending of patient responses. Also, in some embodiments, the precise regimen followed (e.g., number of doses, spacing of doses (e.g., relative to each other or to another event such as administration of another therapy), amount of doses, etc. may be different for one or more cycles as compared with one or more other cycles.

    [0170] By using any of the routes of administrations, dosages, and/or regimens as described herein, a CD38 Modulating Antibody Agent as described herein can be identified, characterized, and/or validated, for example, taking into account one or more criteria that are measured in the patients using biopsies, blood samples, and/or other clinical criteria. In some embodiments, as an alternative or in addition to direct evaluation of tumor size and/or metastasis, therapeutic efficacy of a CD38 Modulating Antibody Agent as described herein can be determined in methods wherein one or more different general criteria are evaluated: direct cytotoxicity on cancer cells (apoptosis and necrosis of cancer cells), increase of tumor infiltrating, immune cells (such as CD4-positive and/or CD8-positive tumor infiltrating T cells), increase in immune cells that circulates in blood (total populations or specific sub-populations of lymphocytes, NK cells, monocytes, dendritic cells, macrophages, B cells, etc.), and/or presenting some differential expression pre- versus post-treatment only in either responding or non-responding patients (as determined by RNA sequencing, mass flow cytometry, and/or other mass sequencing approach). Alternatively or additionally, in some embodiments, such identification, characterization, and/or validation may involve the follow-up at molecular level by screening the mRNA and/or protein expression of one or more specific proteins or sets of proteins. In some embodiments, one or more such techniques may allow identification or relevant information for evaluating the response to a CD38 Modulating Antibody Agent as described herein, for example that may be is related to tissue distribution and/or markers for specific cell populations within (or nearby) the tumor and/or circulating in blood.

    [0171] Such approaches and immune-biological data may allow determination not only of one or more efficacy and/or safety parameters or characteristics, but in some embodiments, can provide a rationale for choosing a particular dose, route or dosing regimen, for example that may be utilized in one or more clinical trials for a given indication, alone and/or in combination with other drugs, standard-of-care protocols, or immunotherapies that can provide further therapeutic benefits. Thus, in a series of further embodiments of the invention, a CD38 Modulating Antibody Agent as described herein is used in a method of treating a patient suffering from a disease (such as cancer) or preventing a disease (such as cancer) after determining the combined presence (and/or absence) of expression at RNA and/or protein level for one or more genes in cells or tissues of the patient (such as a tumor, a blood sample, or a blood fraction), post- or pre-treatment with such a formulation. Such methods may allow therefore defining a one or more biomarkers, or a more complex gene expression signature (or cell population distribution) that is associated to the therapeutically effective amount of a desirable CD38 Modulating Antibody Agent, the therapeutically relevant biomarker(s) that predicts that a subject may have an anti-tumor or anti-infective response after the treatment with a CD38 Modulating Antibody Agent as described herein, or the therapeutically relevant biomarker(s) that predicts that a subject may respond to the treatment with a compound after the treatment with a CD38 Modulating Antibody Agent.

    [0172] Alternatively or additionally, in some embodiments, dosing and administration for a particular CD38 Modulating Antibody Agent as disclosed herein can be preliminarily established and/or later evaluated in view of CD38 expression in human cancers and/or other human tissues, for example by gathering data about CD38 distribution in stromal and/or immune subsets in various cancers, tissues and/or patients. Such data can be generated by using common technologies (such as flow cytometry, mass cytometry, immunohistochemistry or mRNA expression libraries) across common cancer types and/or tissues (central nervous system, Esophagus, Stomach, Liver, Colon, Rectum, Lung, Bladder, Heart, Kidney, Thyroid, Pancreas, Uterus, Skin, Breast, Ovary, Prostate and testis) for identifying relationship between CD38 expression in various immune and non-immune subpopulations and/or its relation with cell infiltrate measures and/or cancer-relevant markers associated with sub-sets of cancer cells or immune cells (such as Foxp3 and PD-1/PD-L1). CD38 expression can be confined (or not) to immune subsets in tumor tissue (such as in NK cells and other effector or regulatory immune cells), and correlations between CD38 expression and immune checkpoint inhibitors can be determined if being positive, thus suggesting appropriate uses of CD38 Modulating Antibody Agents in combinations with compounds targeting such immune checkpoint inhibitors.

    [0173] Articles of Manufacture and Kits; In some embodiments of the invention, a CD38 Modulating Antibody Agent as described herein is provided in a separate article of manufacture. In some embodiments of the invention, an article of manufacture containing a CD38 Modulating Antibody Agent is provided in or with a container with a label. Suitable containers may include, for example, bottles, vials, syringes, and test tubes. In some embodiments, a container may be formed from any or a variety of materials such as glass or plastic. In some embodiments, a container holds a composition that is effective for treating a particular disease, disorder, or condition, or stage or type thereof. In some embodiments, a container may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). For example, in some embodiments, compositions comprising a CD38 Modulating Antibody Agent as described herein is packaged in clear glass vials with a rubber stopper and an aluminium seal. The label on, or associated with, the container indicates that the composition is used for treating the condition of choice.

    [0174] In some embodiments, an article of manufacture may further comprise a separate container comprising a pharmaceutically acceptable buffer, such as phosphate-buffered saline, Ringer's solution and dextrose solution and/or may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, syringes, and package inserts with instructions for use. For example, in some embodiments, an article of manufacture may allow providing each or the agent in an intravenous formulation as a sterile aqueous solution containing a total of 2 mg, 5 mg, 10 mg, 20 mg, 50 mg, or more that are formulated, with appropriate diluents and buffers, at a final concentration of 0.1 mg/ml, 1 mg/ml, 10 mg/ml, or at a higher concentration.

    [0175] In some embodiments, a CD38 Modulating Antibody Agent as described herein can be provided within the kits-of-parts in the form of lyophilized is to be reconstituted with any appropriate aqueous solution that provided or not with the kits, or other types of dosage unit using any compatible pharmaceutical carrier. One or more unit dosage forms of a CD38 Modulating Antibody Agent may be provided in a pack or dispenser device. Such a pack or device may, for example, comprise metal or plastic foil, such as a blister pack. In order to use correctly such kits-of-parts, it may further comprise buffers, diluents, filters, needles, syringes, and package inserts with instructions for use in the treatment of cancer.

    [0176] In some embodiments, instructions that are associated with an article of manufacture or the kits as described herein may be in the form of a label, a leaflet, a publication, a recording, a diagram, or any other means that can be used to inform about the correct use and/or monitoring of the possible effects of the agents, formulations, and other materials in the article of manufacture and/or in the kit. Instructions may be provided together with the article of manufacture and/or in the kit.

    EXAMPLES

    Example 1: Generation of Antibodies That Bind CD38 in Vitro

    Materials & Methods

    [0177] CD38 antigen preparation. Recombinant, Histidine-tagged extracellular domain of human, Cynomolgus monkey (Cyno), and murine CD38 proteins were purchased from Sino Biological Inc. Protein reagent biotinylation was done using the EZ-Link Sulfo-NHS-Biotinylation Kit (Thermo Scientific, Cat #21425). The CD38 antigen was concentrated to -1mg/mL and buffer exchanged into PBS before addition of 1:7.5 molar ratio biotinylation reagents (EZ-Link Sulfo-NHS-Biotinylation Kit, Thermo Scientific, Cat #21425). The mixture was held at 4° C. overnight prior to another buffer exchange to remove free biotin in the solution. Biotinylation was confirmed through Streptavidin sensor binding of the labelled proteins.

    [0178] Library interrogation and selection methodology for isolation of anti-CD38 antibodies. Eight naïve human synthetic yeast libraries each of ˜10.sup.9 diversity were designed, generated, and propagated for high-throughput screening and selection of yeast cell lines expressing monoclonal antibodies as described previously (Xu Y et al, 2013; WO2009036379; WO2010105256; WO2012009568). Eight parallel selections were performed, using the eight naïve libraries for monomeric human CD38-based selection.

    [0179] For the first two rounds of selection, a magnetic bead sorting technique utilizing the Miltenyi MACs system was performed, essentially as described (Siegel et al., 2004). Briefly, yeast cells (˜10.sup.10 cells/library) were incubated with 3 ml of 100 nM biotinylated monomeric human CD38 antigen for 15 minutes at room temperature in FACS wash buffer PBS with 0.1% BSA. After washing once with 50 ml ice-cold wash buffer, the cell pellet was re-suspended in 40 mL wash buffer, and 500 μl Streptavidin MicroBeads (Miltenyi Biotec, Germany. Cat #130-048-101) were added to the yeast cells and incubated for 15 minutes at 4° C. Next, the yeast cells were pelleted, resuspended in 5 mL wash buffer, and loaded onto a MACS LS column (Miltenyi Biotec, Germany. Cat. No. 130-042-401). After the 5 mL was loaded, the column was washed 3 times with 3 ml FACS wash buffer. Column was removed from magnetic field, yeast cells were eluted with 5 mL growth media, and then grown overnight.

    [0180] Subsequent to the two MACS rounds, five rounds of sorting were performed using flow cytometry (FACS). For the first round of FACS selection, approximately 4×10.sup.7 yeast cells were pelleted, washed three times with wash buffer, and incubated with 100 nM of each the biotinylated monomeric human, murine, and Cyno CD38 antigen for 10 minutes at room temperature. Yeast cells were then washed twice and stained with goat anti-human F(ab')2 kappa-FITC diluted 1:100 (Southern Biotech, USA; Cat. No. 2062-02) and either streptavidin-Alexa Fluor 633 (Life Technologies, USA; Cat. No. S21375) diluted 1:500, or Extravidin-phycoerthyrin (Sigma-Aldrich, USA; Cat. No. E4011) diluted 1:50, secondary reagents for 15 minutes at 4° C. After washing twice with ice-cold wash buffer, cell pellets were resuspended in 0.4 mL wash buffer and transferred to strainer-capped sort tubes. Sorting was performed using a FACS ARIA sorter (BD Biosciences) and sort gates were determined to select only CD38 binding. Murine- and Cyno-selected populations from the first FACS round were combined into two pools. These pools were then sorted for human CD38 binding to identify cross-reactive binders in the second FACS round to decrease reagent polyspecific binders (Xu Y et al., 2013). The fourth FACS round consisted predominantly of positive selection using 100 nM biotinylated monomeric CD38 as antigen. A sample of the selected clones were plated and sequenced.

    [0181] Affinity Maturation of clones identified in naïve selections. Heavy chains from the fourth FACS sorting selection round outputs were used to prepare light chain diversification libraries used for four additional selection rounds. The first selection round involved Miltenyi MACs beads conjugated with either 100 nM biotinylated monomeric human CD38 as antigen or 200 nM biotinylated monomeric murine CD38 as antigen. Subsequent to the MACs bead selections, three rounds of FACS sorting were performed. The first FACS round involved either human CD38 at 100 nM or 10 nM or murine CD38 at 200 nM. In parallel to the second FACS round described above, competition selections were performed with 75-100 nM of competitor IgG. After a selection round, a third positive sort with human CD38 at 1 or 10 nM was done before plating. Individual colonies from each FACS selection round were picked for sequencing IgG.

    [0182] IgG and Fab production & purification. Yeast clones were grown to saturation and then induced for 48 hrs at 30° C. with shaking. After induction, yeast cells were pelleted and the supernatants were harvested for purification. IgGs were purified using a Protein A column and eluted with acetic acid, pH 2.0. Fab fragments were generated by papain digestion and purified over CaptureSelect IgG-CH1 affinity matrix (Life Technologies; Cat. No. 1943200250).

    [0183] Affinity Measurements of anti-CD38 Antibodies The affinity for the CD38 antibodies was determined by measuring their K.sub.D by Forte Bio. Forte Bio affinity measurements were performed by loading IgGs on-line onto AHQ sensors as described (Estep P et al., 2013). Briefly, sensors were equilibrated off-line in assay buffer for 30 minutes and then monitored on-line for 60 seconds for baseline establishment. For avid binding measurement, sensors with loaded IgGs were exposed to 200 nM of human, cyno, or murine CD38 for 3 minutes, afterwards they were transferred to assay buffer for 3 minutes for off-rate measurement. Monovalent binding measurements were obtained by loading biotinylated CD38 monomer on SA sensors followed by exposure to 200 nM antibody. Kinetics data were fit using a 1:1 binding model of data analysis software provided by Forte Bio. The Kd values that were established in this assay for the reference agonistic anti-CD38 antibodies are the following: for IB4, 0.9×10.sup.−8 M for human CD38 and no binding to cynomolgus CD38, for IB4.

    [0184] Avidity binding measurements of anti-CD38 Antibodies: Ni-NTA sensors were equilibrated off-line in assay buffer for 30 minutes and then monitored on-line for 60 seconds for baseline establishment. They were loaded with 4.2 nM antigen (recombinant human CD38 HIS tagged) for 50 minutes, afterwards they were transferred to assay buffer for 0.5 minutes for wash and again for 1 min in assay buffer for base line determination. Then the antibody was associated at different concentrations (as described in FIGS. 7 and 12) for 50 min. Afterwards they were transferred to assay buffer for 30 minutes for off-rate measurement. Kinetics data were fit using a 1:1 binding model in the data analysis software provided by ForteBio.

    [0185] Alternatively, the affinity for the anti-human CD38 antibodies was determined by measuring their K.sub.D by SPR in a Biacore 2000 using a CM-5 Sensor chip with an ambient experiment temperature of 25° C. Anti-human antibody was initially immobilised across all flow cells in analysis buffer (pH 7.4, 10mM HEPES, 150mM NaCI, 3mM EDTA, 0.05% Tween 20) to an RU of between 12,000-14,000 over 10 minutes. The ligand (antibody test articles) was sub sequentially loaded to a capture level between 54-208RU. The analyte (recombinant human CD38 his tagged) was then associated in analysis buffer from a 2-fold dilution starting at 3200 nM with a lowest concentration of 0.78nM for 6 minutes. Dissociation was performed in analysis buffer over 10 minutes. Regeneration steps between sample concentrations were performed in 3 M MgCl.sub.2, three times for 0.5 minutes. A flow rate of 25 μl/min was maintained throughout the process. Kinetics data were fit using a global fit on the analysis software provided by Biacore with reference subtraction.

    [0186] Epitope Binning: Epitope binning of the antibodies was performed on a Forte Bio Octet Red384 system (Pall Forte Bio Corp., USA) using a standard sandwich binning assay. The anti-human CD38 antibody was loaded onto AHQ sensors and unoccupied Fc-binding sites on the sensor were blocked with a non-relevant human IgG1 antibody. Sensors were exposed to 100 nM target antigen followed by a second anti-CD38 antibody, the reference monoclonal agonistic mouse anti-human CD38 antibodies (IB4, kindly provided by Prof. F. Malavasi at Univ. Torino, Italy). Data was processed using Forte Bio Data Analysis Software 7.0. Additional binding by second antibody after antigen association indicates an unoccupied epitope, while no binding indicates epitope blocking.

    [0187] Binding of anti-CD38 Antibodies to CD38-expressing cells The candidate hits are evaluated by analysing the binding to purified cynomolgus T cells. To this aim cynomolgus pan T cells were stained with 20 μg/ml of aCD38-b-348 or DARA followed by a semi-log serial dilution (7 points) for 30 minutes on ice. Unbound primary antibody was removed by washing followed by staining with a secondary antibody (5 μg/ml) 30 minutes on ice. All samples were stained in triplicates with appropriate CD3, CD4 and CD8 cross-reactive antibodies. Samples were measured by flow cytometry. For data analysis live cells were gated using FSC vs SSC parameters during sample acquisition. Mean fluorescence intensities (MFI) of stained cells were plotted on an XY chart, graphing MFI against the log of the concentration and the data fit to a non-linear regression curve from which the EC50 was calculated.

    [0188] Alternatively binding was evaluated in human PBMC. To this aim, PBMCs were prepared from whole blood from 3 human donors and incubated for 30 minutes with aCD38-b-348 or DARA at final concentrations of 1μM, 200 nM, 40 nM, 8 nM, 1.6 nM, 320 pM, 64 pM, 13 pM and 2.5 pM. Cells were then washed and labelled with an AF488 secondary antibody. Cells were then incubated with additional surface staining antibodies: anti-CD3 PE-Cy7, anti-CD4 APC and anti-CD8 BV451. Sample acquisition was performed using 8-colour (three laser) BD FACSCanto II cytometer, running on the BD FACSDiva software (BD Biosciences). Post-analysis processing and was conducted using FCS Express (v3.0) software (DeNovo software). The relative proportions (%) of the different cell populations and Median Fluorescence Intensity (MFI) data were reported to 2 decimal places.

    [0189] Recloning, producing, and characterizing of aCD38-b-348 as human IgG1 expressed in mammalian cells. Synthesis of codon optimized VH and VL coding sequences for the antibody was performed by Genewiz. cDNAs of variable regions were cloned into the antibody expression vector (Icosagen, EST) containing human IgG1 heavy chain and kappa light chain constant regions (P01857 and P01834 respectively). Full length heavy and light chain cDNAs were verified by sequencing in final vectors and then recloned for expressing them using the QMCF Technology (Icosagen) a stable episomal expression system that uses CHO-based cells (CHOEBNALT85) and appropriate vectors for production of recombinant proteins, antibodies, CHOEBNALT85 cells were transfected with 1 μg of the expression plasmids for antibody production. 48 h after the transfection 700 μg/ml of G418 was added to select plasmid containing cell population. For the production, temperature was shifted to 30° C. and the cultures were additionally fed. At the end of the production the culture supernatants were clarified by centrifugation (1000 g, 30 minutes, and 15° C.), PMSF was added and supernatants were processed or frozen until purification. hIgG1 antibodies were purified by MabSelect SuRe affinity chromatography followed by Superdex 200 gel filtration into either 25 mM NaOAc pH 5,5; 50 mM NaCl or PBS. Human IgG1 antibodies produced in CHOEBNALT85 cells were characterized for affinity towards recombinant human CD38, cross reactivity towards murine, rat, rabbit and cyno CD38 and epitope binning versus the selected CD38 binding antibodies using recombinant rabbit CD38 (65003-T08H-20; Sino Biological) and recombinant rat CD38: _(80229-R08H-20; Sino Biological).

    [0190] aCD38-b-348 epitope mapping Different sets of linear, single loop, β-turn mimics, disulfide bridge mimics, discontinuous disulfide bridges, discontinuous epitope mimics peptides representing the human CD38 sequence (Uniprot record no. P28907) were synthesized using solid-phase Fmoc synthesis (Pepscan BV, The Netherlands; Timmermann P et al., 2007; Langedijk JP et al., 2011). The binding of antibody to each of the synthesized peptides was tested in a pepscan-based ELISA (Pepscan, The Netherlands). The peptide arrays were incubated with primary antibody solution (overnight at 4° C.). After washing, the peptide arrays were incubated with a 1/1000dilution of an appropriate antibody peroxidase conjugate (2010-05; Southern Biotech) for one hour at 25° C. After washing, the peroxidase substrate 2,2′-azino-di-3-ethylbenzthiazoline sulfonate (ABTS) and 20 μl/ml of 3 percent H2O2 were added. After one hour, the color development was measured. The color development was quantified with a charge coupled device (CCD) - camera and an image processing system. The values obtained from the CCD camera range from 0 to 3000 mAU, similar to a standard 96-well plate ELISA-reader. To verify the quality of the synthesized peptides, a separate set of positive and negative control peptides was synthesized in parallel and screened with irrelevant, control antibodies.

    [0191] Alanine scanning was performed to confirm the epitope. Alanine scanning was performed using Integral Molecular's epitope mapping platform based on Shotgun Mutagenesis to further characterize the epitopes of the mAbs. The coding region for full-length CD38 protein was successfully codon-optimized, synthesized, and subcloned into a mammalian high-expression vector. This parental construct was then sequence-verified and validated for mammalian cell expression by immunodetection. Conditions for binding and screening of aCD38-b-348 (mAb and Fab) using high-throughput flow cytometry were optimized using wild-type CD38 cloned into a proprietary vector and expressed in HEK-293T cells.

    [0192] In order to map the epitopes of the antibody an alanine-scan library of CD38 was constructed. The antibodies (mAb and Fab) were then screened for binding to each individual CD38 variant, allowing identification of the CD38 contact residues critical for the test mAbs binding.

    [0193] Anti-human CD38 Ab Competition Assays: Antibody competitions were performed on a Forte Bio Octet Red96 system (Pall Forte Bio Corp., USA) using a standard sequential binding assay. 0.625ug/mL of recombinant human CD38his tagged was loaded onto Ni-NTA Biosensors for 300s. After wash for 15s and a base line step for 60s on kinetic buffer sensors were exposed to 66.6 nM of first antibody (Daratumumab) for 600s followed by a second anti-CD38 antibody (Daratumumab (control) or aCD38-b-348) (also at 66.6nM for 600s). Data was processed using Forte Bio Data Analysis Software 9.0. Additional binding by a second antibody indicates an unoccupied epitope (no competition for the epitope), while no binding indicates epitope blocking (competition for the epitope).

    Results

    [0194] Monoclonal antibodies (mAb) binding to recombinant human CD38 extracellular protein sequence (rhCD38) have been isolated using a yeast-based antibody presentation library as described in the Materials & Methods. These antibodies were sequenced and unique clones were produced in yeast cells (Barnard GC et al., 2010). The cell culture supernatants for each yeast clone expressing a unique antibody sequence was screened for rhCD38 binding.

    [0195] The KD values (for affinity and avidity measurements) and crossing binning analysis for selected antibodies are provided in Table 1A:

    TABLE-US-00012 TABLE 1A Affinity Avidity Epitope K.sub.D Human K.sub.D Human K.sub.D Human Cross- CD38-HIS CD38-HIS CD38-HIS binning Monovalent Monovalent Monovalent Antibody group (M) (Octet) Isotype (M) (Biacore) (M) (Octet) Isotype aCD38-b-348 B 8.81E−09 IgG1 2.00E−09 1.77E−10 IgG1 aCD38-b-348 B 9.24E−09 IgG4 — — — Daratumumab F 8.28E−08 IgG1 — 1.80E−10 IgG1

    [0196] Binding of anti-CD38 antibodies to recombinant monovalent human CD38 measured by Octet and Biacore and compared to Daratumumab, is shown in FIGS. 7, 12, and 19A.

    [0197] The results of the epitope mapping and confirmation by alanine scanning are shown in Table 1B.

    TABLE-US-00013 TABLE 1B Alanine Antibody Scanning Pepscan aCD38-b-348 R78 .sub.65ARCVKYTEIHPEMRH.sub.79

    [0198] Based on the binding to rhCD38, sequence uniqueness and expression levels a panel of mAbs was identified. These antibodies were further characterized for binding to recombinant Cynomolgus monkey and mouse CD38 extracellular domain protein sequences. In addition, epitope binning was performed to determine whether the identified antibodies bind to epitopes overlapping with those of the reference agonistic anti-CD38 antibody IB4 (Ausiello CM et al., 2000; Ferrero E et al., 2004). The clones were characterized presenting IgG binding values to monovalent rhCD38 and/or recombinant cynomolgus CD38 extracellular protein sequences that is comprised between 10.sup.−8 M and 10.sup.−10 M. In addition, each antibody was characterized as competing or not with reference agonistic anti-CD38 antibody IB4 (or commercially available Daratumumab, DARA). The selected antibodies belong to different cross binning groups, as shown in Table 1. The antibody clones were also evaluated at the level of binding to cynomolgus pan T cells (FIG. 3A) and human PBMC (FIG. 3B) was confirmed.

    [0199] Finally, in order to eliminate antibody sequences that would be prone to aggregation and non-specific interaction, the antibodies were screened in a Poly Specific Reagent (PSR) assay and Affinity-Capture Self-Interaction Nanoparticle Spectroscopy (AC-SINS), an approach that allows high-throughput screening for early-stage antibody development (Liu Y et al., 2014). None of the antibodies scored positive in the latter assays and as such were not removed from the panel.

    [0200] Among the selected hits that were sequenced and characterized as described above, the clone aCD38-b-348 is an antibody presenting novel complementarity determining regions (CDRs; FIG. 2A) that competes for human CD38 binding neither with IB4 nor with Daratumumab. Indeed, the epitope mapping study that has been performed using Pepscan technology would indicate that aCD38-b-348 binds human CD38 in a region that is not only distinct from the one published for Daratumumab (two beta-strands containing amino acids 233-246 and 267-280; FIG. 2B) or the ones that are reported for other anti-human CD38 antibodies (see table 2 in WO2015123687) and binds human and cynomolgus CD38 extracellular protein sequences with a Kd value in the 10.sup.−9 M range. The alanine scanning confirms the epitope region for aCD38-b-348 and in particular that amino acid residue 78 of human CD38 is involved in binding. The antibody competition assay showed that Daratumumab does not compete with aCD38-b-348 for the same epitope (FIG. 23).

    [0201] Thus, the aCD38-b-348 sequences (FIG. 2A) identify antibodies that specifically bind CD38, and whose agonistic activities associated to the functional features defining CD38 Modulating Antibody Agents, as that term is used herein, can be functionally evaluated by cell-based assays or animal models. The analysis of aCD38-b-348-LCDR3 shows the presence of a DG (Asp-Gly) motif which represents a potential target for modification during manufacturing that may affect some of the antibody properties. At this scope, aCD38-b-348-based antibody libraries in which either one or both residues are substituted and, among all such mutants, only a limited number of them maintained the binding to human CD38, for example as expressed on the surface of Daudi cells (see Example 2). In this manner, the corresponding aCD38-b-348-based antibody variants can be tested as maintaining full properties of CD38 Modulating Antibody Agents, or simply having CD38 binding properties. Further validation of these variants may be pursued by using the assays disclosed in the Examples.

    Example 2: Cell-Based Models for Validating CD38 Modulating Antibody Agents

    Materials & Methods

    [0202] In vitro T cell activation assay: Previously frozen primary human pan T cells (Stemcell Technologies) were labelled with eFluor450 fluorescent dye (Life Technologies) and 0.15×10.sup.6 cells were incubated per well for 72 hrs in 96-well plates pre-coated with anti-CD3 antibody (0.1 μg/ml coating concentration, clone OKT3, eBiosciences) and anti-CD38 modulating antibodies coated at concentrations of 10, 5 and 2.5 μg/ml in RPMI 1640 (Life Technologies) containing 10% FBS (Sigma), 2 mM L-Glutamine (Life Technologies) and 10,000 U/ml Pen-Strep (Sigma). Readout of T cell proliferation was done by acquisition on the flow cytometer, excluding dead cells labelled with a viability dye (Zombie NIR, BioLegend) and discriminating surface markers by staining with fluorochrome labelled antibodies (CD8-FITC clone HIT8a eBiosciences, CD25-PE clone M-A251 Biolegend, CD4-BV510 clone RPA-T4 BioLegend, CD38-PE-Cy7 clone HB_7, eBiosciences, CD137-APC clone 4B4-1 BioLegend). Cytokine analysis in supernatants was conducted using the Meso Scale Discovery MSD platform, determining the expression of IFNg, IL2IL10, TNFa, and GM-CSF according to the manufacturer's instructions (Multiplex assay kits, Meso Scale Discovery; asterisk in figure indicates values above fit curve range).

    [0203] In vitro T cell activation by NFAT signaling assay: Jurkat cells stably transfected with a luciferase reporter system (BPS Biosciences) were incubated at 4° C. for 20 minutes in PBS (GIBCO) with different concentrations of mAbs (0.2, 1, 5, 10, 20, 40μg/ml) against CD38 (or control IgG), followed by cell pelleting, removal of the PBS supernatant and resuspension of the cells in cold growth medium (RPMI (ATCC)+10% FBS (SIGMA)) supplemented with 40 μg/ml F(Ab′)2-fragment cross-linking Ab (Jackson ImmunoResearch) and in the presence of 1 ug/ml soluble CD3 mAbs. 10 minutes after the cross-linking antibody has been added, the cells were transferred to 37° C. incubation. 6-24 h after the 37° C. incubation started, the cells were lysed and the luciferase activity was measured by mean of luminescence release from the hydrolysis of a specific luciferase substrate, following manufacturer instruction (BPS Bioscience one-step luciferase assay kit). NFAT signaling is measured as Relative luminescence units (RLU).

    [0204] In vitro NK cell activation assay. Human PBMC were labelled with Cell Trace violet proliferation dye (Life Technologies) and cultured in the presence of MDA-MB-231 cells in a ratio of 100:1 (culture medium IMDM, Life Technologies, 10% human serum heat-inactivated, Sigma, 10,000 U/ml Pen-Strep, Sigma) for 5 days. Anti-CD38 antibody was added or control cells were left untreated. Readout for proliferation quantified by dilution of fluorescent dye was done by FACS analysis. Cells were labelled with fluorochrome conjugated antibodies and NK cells were gated by excluding dead cells (Zombie NIR dye, Biolegend), gating on CD45+hematopoietic cells (CD45-PE-Cy7, Biolegend), further gating on CD3 negative CD56 positive cells (CD56-BV711 clone H130 Biolegend; CD3-BV510 clone OKT3 Biolegend).

    [0205] In vitro ADCP assay. Antibody-dependent cell-mediated phagocytosis (ADCP) was performed for the characterization of anti-human CD38 antibodies using in-vitro differentiated Tregs as target cells and monocyte-derived macrophages as the effector cells. Different effector to target ratios were evaluated. Target cells were added at 1×10.sup.4 cells/well while the effector cells were added at (1×10.sup.4, 2.5×10.sup.4, 5×10.sup.4 or 1×10.sup.5 cells/well). Anti-human CD38 antibodies were evaluated at 3 concentrations (1 μg/ml; 10 μg/ml and 50 μg/ml). The assay performed using the following protocol: PBMC were isolated from leucocyte cones by Ficoll gradient centrifugation. CD14+cells were isolated using CD14 Microbeads (CDK006, Miltenyi Biotec). Monocytes were cultured for 7 days in the presence of 50ng/ml M-CSF in RPMI 1640 (Life Technologies) containing 10% FBS (Sigma), 2 mM L-Glutamine (Life Technologies) and 10,000 U/ml Pen-Strep (Sigma), fresh media containing M-CSF was added after 4 days. Regulatory T cells (Treg) were isolated using the Human Treg Cell Differentiation Kit (130-050-201, R&D Systems). These cells were incubated in a 37° C., 5% CO.sub.2 humidified incubator for 5 days. At day 7 macrophages and eFluor450 labelled (eBiosciences) Tregs were cocultured overnight in ratios described above in the presence of CD38 or control antibodies. Phagocytosis of Tregs was determined by flow cytometry gating on CD14+cells (stained with CD14-PE-Cy7 clone MfP9 BD Biosciences) positive for the Treg label (eFluor450 dye).

    [0206] In vitro ADCP reporter assay: Promega Bioassay core kit G9901 was used. 5000 Raji cells/well of target wells were plated in 25ul medium per well using a 96 well white polystyrene plate (Costar Cat#3917). Test antibodies were serial diluted 1:3 in a separate plate. 25 ul serial diluted antibody was added to the cells. 50000 cells/well of the effector cells were added to the plate (25 ul/well). Plates were incubated over night for 20 hours at 37° C. The next day the plate was removed from the incubator and kept at room temperature for 20 minutes. 60u1 Bio-Glo Luciferase assay substrate were added to each well, incubated for 30 minutes. Luminsence was read using the GloMax Multi Detection System. Cell culture medium: RPMI +4% Low IgG Serum.

    [0207] In vitro ADCC assay: Antibody-dependent cell-mediated cytotoxicity assays (ADCC assays) were performed for the characterization of anti-human CD38 antibodies using Daudi (CD38 positive) human cell line as a target cell with human PBMC as the source of effector cells. Effector to Target ratios would be evaluated at 50 to 1 or 25 to 1 with test articles (anti-CD38 primary antibodies or Rituximab as a control) to be evaluated with top concentration of 10 μg/ml followed by a log series (7 points) in triplicate for 4 hours at 37° C. 5% CO2. PBMCs were primed with IL-2 and IL-2 was present during co-culture assays. Prior to in-vitro culture, target cell lines were labelled with 1 μM Calcein AM and incubated with 2.5 mM probenecid. Lysed cells release the loaded Calcein into the supernatant, which allows for fluorescent measurement. Calcein AM release was analysed by excel and GraphPad software analysis to generate dose response curves by normalization where 1% saponin treatment values will be used to determine maximal lysis. Percentage target cell lysis was plotted on an XY chart, graphing normalized Calcein AM percentage release against the log of the concentration, and the data fit to a no-linear regression curve from which the EC50 was calculated.

    [0208] In vitro CDC assay: CDC activity to CD38 expressing human cell lines (Daudi) was examined by treating cells with test articles (anti-CD38 primary antibodies or Rituximab as control) at a top concentration of 10μg/ml followed by a log dilution series (7 points) in triplicate with a final concentration of 10% normal human serum complement. Samples were cultured for 3 hours at 37° C. 5% CO2. Following culture conditions, cells washed and re-suspended in 1× PBS with propidium iodide (PI) at a final concentration of 5μg/ml prior to flow cytometry analysis. Total cells were examined by flow cytometry during sample acquisition. Percentage of PI positive cells were plotted on an XY chart, graphing percentage PI against the log of the concentration, and the data fit to a non-linear regression curve from which the EC50 is calculated.

    [0209] Direct cell death assay. Direct proapoptotic activity to CD38 expressing human cell lines (Daudi) was examined by treating cells with test articles (anti-CD38 primary antibodies) or Rituximab as a control at a top concentration of 10μg/ml followed by a log dilution series (7 points) in triplicate. Cell death by Fcγ receptor-mediated cross-linking activity was examined by treating cells with test articles (anti-CD38 primary antibodies or Rituximab) as a control at a top concentration of 10 μg/ml followed by a log serial dilution (7 points) in triplicate followed by 5μg/ml rabbit anti-human Fcy F(ab')2 (secondary antibody). Samples were cultured for 24 hours at 37° C. 5% CO2. Following culture conditions, cells were washed and resuspended in Annexin V binding buffer and 7-AAD to examine cell death by flow cytometry analysis. Total cells were examined by flow cytometry during sample acquisition. Percentage of late apoptotic cells were plotted on an XY chart, graphing percentage Annexin V-positive and 7-AAD-positive cells against the log of the concentration and the data fit to a non-linear regression from which the EC50 is calculated.

    [0210] Enzymatic activities of CD38 on the cell surface (cyclase and NADase/hydrolase activities): both cyclase and NADase activity of CD38 were measured on the cell surface of Daudi cells and in Jurkat cells by monitoring the CD38-dependent conversion of NGD+ (Sigma) and E-NAD+(Sigma) into their respective fluorescent products: cGDPR (cyclic product from NDG+) and 5′-eAMP (hydrolysis product of E-NAD+). 150 thousand Daudi cells were incubated for 20 minutes on ice with 10μg/ml antibodies in 75μl of PBS (Thermo Fisher); after 20 minutes, 75 μl of enzymatic reaction buffer (or control buffers) were added and the cells were incubated at 37° C. for 45 minutes for Daudi cells and for 60 minutes for Jurkat cells. The enzymatic reaction buffer included 20 mM UltraPure Tris-HCI Buffer (Thermo Fisher), pH 7.5 in PBS, (Thermo Fisher) and 200 pM of either NGD+or E-NAD+. After the incubation at 37° C., the cells were pelleted by mean of centrifugation at 550×g and 100 μl of supernatant was utilised for fluorescence measurements in a Molecular Device SpectraMax MiniMax 300 plate reader (excitation wavelength 300 and emission wavelength 410).

    [0211] Statistics. Prism software (GraphPad) was used to perform curve fitting and to determine EC50 values and maximal activity.

    Results

    [0212] The EC50 values and percentage lysis results from the ADCC and CDC assays are shown in Tables 2, 3 and 4, compared to the results for daratumumab in the same experiment:

    TABLE-US-00014 TABLE 2 ADCC data for Target Daudi cells: Max. EC50 Max. EC50 lysis ug/ml Lysis Antibody Experiment ug/ml % DARA DARA aCD38-b-348 6 0.00032 60 0.00194 45 aCD38-b-348 7 0.0008 39 0.00317 31 aCD38-b-348 8 0.00042 50 — —

    TABLE-US-00015 TABLE 3 CDC data - 10% complement, target Daudi cells: Max. EC50 Max. EC50 lysis ug/ml Lysis Antibody Experiment ug/ml % DARA DARA aCD38-b-348 15 0.17 97.1 0.05 97.8 aCD38-b-348 16 0.34 87.8 0.13 96.8 aCD38-b-348 17 0.26 89.9 0.13 96.8

    TABLE-US-00016 TABLE 4 CDC data - 10% complement, target Raji cells: Max. EC50 Max. EC50 lysis ug/ml Lysis Antibody ug/ml % DARA DARA aCD38-b-348 0.3 41.7 0.04 54.7 aCD38-b-348 0.17 44.4 0.04 41.7 (repeat)

    [0213] The aCD38-b-348 candidate antibody, as other antibodies that have been characterized in Example 1, has been further evaluated with respect to immune cells. In a first series of experiments, aCD38-b-348 shows dose dependent binding to human and cyno T cells (FIG. 3A and B). When tested using T cells, for instance when aCD38-b-348 is used for coating a plate for culturing such cells, aCD38-b-348 strongly increases human T cell activation while the reference anti-CD38 antibody (DARA) is displaying much weaker agonist activity (FIG. 4A). When aCD38-b-348 is tested in solution, this antibody induces proliferation and activation of human primary NK cells co-cultured with a breast cancer cell line (FIG. 4B). The agonist activity of aCD38-b-348 is further emphasized by stronger proinflammatory cytokine secretion by human T cells triggered by aCD38-b-348 when compared to DARA (FIG. 4C). Killer activities of aCD38-b-348 appears exerted via inducing macrophage mediated phagocytosis of CD38 expression target cells (FIG. 5A), e.g. regulatory T cells. This effect is comparable to DARA. In addition, aCD38-b-348 and DARA show comparable activity in ADCC assays, but only the latter one present CDC activity (FIG. 5B). The decreased CDC effect triggered by aCD38-b-348 would provide an anti-CD38 antibody having increased safety due to reduced infusion site reaction. DARA and aCD38-b-348 show also comparable activity in killing of CD38 expressing tumour cells (Daudi) by human PBMC, even though only the activity of aCD38-b-348 appears enhanced by antibody cross-linking (FIG. 5C). aCD38-b-348 was also shown to have increased ADCP as compared daratumumab in a reporter cell assay (FIG. 8).

    [0214] In addition to the killing activities in vitro, aCD38-b-348 was shown to slightly decrease the cyclase activity of CD38 (FIG. 9A), however DARA more strongly inhibits the cyclase activity in the Jurkat cell assay. aCD38-b-348 showed no effect on the NADase (NAD+hydrolase) activity of CD38, while DARA increases the activity in the Jurkat cell assay (FIG. 9B).

    [0215] In conclusion, aCD38-b-348 has been characterized as an exemplary anti-CD38 antibody that presents the activities of a CD38 Modulating Antibody Agent with respect to immune cells in different experimental set ups.

    [0216] The same assays can be carried out on the variant antibodies provided herein (i.e. variants of aCD38-a-348 having altered DG motifs).

    Example 3: Validation of CD38 Modulating Antibody Agent in Animal Models

    Materials & Methods

    [0217] Lymphoma cells-based models Daudi and Ramos human Burkitt Lymphoma cells were cultured in RPMI 1640 containing 2 mM L-glutamine supplemented with 10% fetal bovine serum +1 mM Na Pyruvate +4.5g/L Glucose +10mM Hepes. Healthy female cb17 SCID mice were obtained from Charles River. Tumors were induced by intravenous injection of 5×10.sup.5 Daudi cells or 10.sup.6 Ramos cells in 200 μL of RPMI 1640 into the caudal vein of the animals. Cell injection was performed 24 to 72 hours after a whole body irradiation with a γ-source (1.44 Gy / mouse, 60Co, BioMep, Bretenieres, France). Mice were randomized into treatment groups by bodyweight, 8 mice per group. Animals from group 1 received intravenous injections of vehicle at 5 ml/kg twice a week for three consecutive weeks (TW×3). Animals from group 2 received intravenous injections of DARA at 10 mg/kg/inj. twice a week for three consecutive weeks (TW×3). Animals from group 3 received intravenous injections of aCD38-b-348 at 10 mg/kg/inj. twice a week for three consecutive weeks (TW×3). Mice were sacrificed after a maximum of 8 weeks.

    Solid Tumour Model

    [0218] Female CB.17 SCID mice were injected with 1×10.sup.7 Ramos tumour cells in 0% Matrigel subcutaneously in the flank, n=10 per group. Treatment started when tumors reached 100-130mm.sup.3 size for twice a week for three weeks. Mice were treated with 10mg/kg intra venously with the antibody aCD38-b-348 compared to daratumumab and a vehicle control. Mice were sacrificed when the tumour volume reached 2000 mm.sup.2 or 43 days after start of treatment, whichever was reached first.

    Results

    [0219] The therapeutic properties of aCD38-b-348 can be tested in animal model for human cancer, in particular using immunocompromised mice where the properties of a CD38 Modulating Antibody Agent with respect to the killing of human tumor cells can be more appropriately evaluated. aCD38-b-348 shows remarkable potency to increase survival of mice intravenously injected with two different types of human lymphoma cells, an effect that is superior to Daratumumab (DARA) (FIG. 6).

    [0220] aCD38-b-348 showed enhanced anti-tumor activity against subcutaneously injected Ramos cells when compared to daratumumab. (FIG. 10).

    [0221] These properties, not only in terms of animal survival but also with concurrent immunological effects can be further investigated in other in vivo models for human tumors (in particular solid cancers) that are based on the injection with either human cancer lines or human primary cancer cells, in which solid tumors grow subcutaneously, as described in the literature (Morton JJ et al. 2016; Holzapfel BM et al., 2015), and in ex vivo models based on the use of tumour samples directly isolated from patients from which tumour cells and immune cells are isolated and tested in vitro for their response to the anti-CD38 antibodies, as measured by cell activation, proliferation, cytokine production and/or cell death. Additional features such as abscopal effects or changes in gene expression in selected tissues or biological materials can be evaluated, possibly by administering aCD38-b-348 in different doses and/or in combination with other anti-cancer agents (such as inhibitors of kinases or of other enzymes, antibodies, radio/chemo-therapy, adjuvants, or vaccines).

    Example 4: Low Dose Anti-CD38 Antibody Increases T Cell Activation in Non-Human Primates

    [0222] Non-human primates (cynomolgus monkeys) were treated with 0.03mg/kg aCD38-b-348 i.v. on days 1 and 8. Peripheral T cell frequencies and activation markers (CD69, CD137 and HLA-DR) were analysed before the first dose, as well as 24 hrs and 5 days after the second dose. T cells showed signs of increased activation after dosing, most prominently by upregulation of CD69 and CD137 on CD4 T cells, and HLA-DR on CD8 T cells. No immune activation-related adverse reactions were observed. The results are shown in FIGS. 14A to F.

    Example 5: Generation of Variants of aCD38-b-348

    [0223] To prevent aspartate isomerisation, a library of potential substitutions for the VL CDR3 DG sequence was generated. Two yeast libraries were generated for aCD38-b-348 in order to remove a DG motif. The first library was based on degenerate primers NNKNNK around both the aspartate and the glycine. This library had a diversity of 400. The second library was based on a degenerate primer NNK focused on the aspartate while preserving the glycine, with a diversity of 20. These libraries were sorted in a single round on human CD38 monomer at 10 nM and a PSR-negative sort was performed. 96 from each lineage were sequenced, produced, and characterized as above. Additionally, a total of five 96-well plates were picked from the NNKNNK libraries to screen for binding to rhCD38 in Octet. A limited number of substitutions were tolerated and the variants showing the best affinities were selected and the variants tested for binding the rhCD3 in Octet. Variants showing the best affinities were selected for mammalian production and further characterisation using the assays as described above in Example 2.

    [0224] Functional characterization of variants: Lymphoma cells-based models: Raji and Ramos human Burkitt Lymphoma cells were cultured in RPMI 1640 containing 2 mM L-glutamine supplemented with 10% fetal bovine serum +1mM Na Pyruvate +4.5 g/L Glucose +10mM Hepes. Healthy female cb17 SCID mice were obtained from Charles River. Tumors were induced by intravenous injection of 5x10.sup.5 Raji cells or 10.sup.6 Ramos cells in 200 μL of RPMI 1640 into the caudal vein of the animals. Cell injection was performed 24 to 72 hours after a whole body irradiation with a γ-source (1.44 Gy/mouse, 60Co, BioMep, Bretenieres, France). Mice were randomized into treatment groups by bodyweight, 10 mice per group. Animals from group 1 received intravenous injections of vehicle at 5 ml/kg twice a week for three consecutive weeks (TW×3). Animals from group 2 received intravenous injections of DARA at 10 mg/kg/inj. twice a week for three consecutive weeks (TW×3). Animals from group 3 received intravenous injections of aCD38-b-348 at 10 mg/kg/inj. twice a week for three consecutive weeks (TW×3). Mice from group 4 received intravenous injections of aCD38-b-348-m2 at 10 mg/kg/inj. twice a week for three consecutive weeks (TW×3). Mice were sacrificed at the time indicated in the figure.

    Results

    [0225] The CDR1-FR2-CDR2-FR3-CDR3 sequence of the VH and VL chains of the variant antibodies are shown in FIG. 15 (SEQ ID NO: 4 and SEQ ID NO: 20 for aCD38-b-348-ml, SEQ ID NO: 4 and SEQ ID NO: 21 for aCD38-b-348-m2, SEQ ID NO: 4 and SEQ ID NO: 22 for aCD38-b-348-m3, SEQ ID NO: 4 and SEQ ID NO: 23 for aCD38-b-348-m4). Daudi cell binding experiments confirmed that binding of the variant antibodies to CD38 was comparable with the parental clones and with daratumumab, see Table 5 and FIG. 16 and FIG. 19.

    TABLE-US-00017 TABLE 5 Octet Biacore LCDR3 Affinity Affinity EC50 Antibody Sequence K.sub.D (M) K.sub.D (M) ug/ml Max MFI aCD38-b-348 QQDGNVYT 5.79E-09  2.0E-9 0.341 2324 (SEQ ID NO: 7) aCD38-b-348- QQEANVYT 2.47E-08 6.30E-08 0.485 1612 m1 (SEQ ID NO: 10) aCD38-b-348- QQDSNVYT 3.99E-08 6.80E-09 0.499 2221 m2 (SEQ ID NO: 11) aCD38-b-348- QQDANVYT 5.51E-08 2.80E-08 0.558 2098 m3 (SEQ ID NO: 12) aCD38-b-348- QQEGNVYT 7.01E-08 2.70E-08 0.299 2020 m4 (SEQ ID NO: 13) Daratumumab — — 0.945 2495

    [0226] The variants showed comparable ADCC activity to the parental clones and daratumumab (FIG. 17). The variants had a lower EC50 ug/ml for ADCC activity than the parental strain but comparable maximum lysis (Table 6).

    TABLE-US-00018 TABLE 6 ADCC target lysis: Antibody EC50 ug/ml Max. % lysis aCD38-b-348 0.0059 44 aCD38-b-348-m1 0.0028 38 aCD38-b-348-m2 0.0025 44 aCD38-b-348-m3 0.0043 39 aCD38-b-348-m4 0.0014 38 Daratumumab 0.0025 58 IgG1 Isotype NA 0

    [0227] Peptide mapping samples were prepared through DTT reduction and iodoacetamide alkylation, digested using trypsin and analyzed on a LC-UV-MS system. The level of isomerized and non isomerized peptides were determined and % of isomerized peptide are shown in Table 7:

    TABLE-US-00019 TABLE 7 Antibody Isotype % isoD aCD38-b-348 igG4 13.0% aCD38-b-348 igG1 15.5% aCD38-b-348-m2 igG1 0.0% aCD38-b-348-m3 igG1 0.0%

    [0228] The therapeutic properties of aCD38-b-348 and its variant aCD38-b-348-m2 were tested in animal models for human cancer, in particular using immunocompromised mice where the properties of a CD38 Modulating Antibody Agent with respect to the killing of human tumour cells can be more appropriately evaluated. aCD38-b-348 variant aCD38-b-348-m2 shows remarkable potency to increase survival of mice intravenously injected with two different types of human lymphoma cells in both models (Raji and Ramos) (FIG. 18).

    Example 6: Analysis of aCD38-b-348 in NK Cells

    NK Cell Degranulation:

    [0229] NK cells isolated from buffy coats of healthy volunteers were either stimulated for 2 days with 500U/ml IL-2 at 2×10.sup.6 cells/ml in RPM11640 media containing 10% FCS, or used freshly isolated without prior IL-2 stimulation. For the functional assay 1 to 1.5×10.sup.6 NK cells were resuspended in DMEM complete media, 100 ul cell suspension were seeded per well in 20 wells of a 96-well plate. 20 ul of media containing CD107a antibody (14 ul antibody pre-mixed in 140 ul media) were added to all wells except to unstained/unstimulated control conditions. Test antibodies aCD38-b-348, daratumumab, and human IgG1 isotype control were added at 10 ug/ml. For positive control 50 ul media containing PMA (50 ng/ml) and lonomycin (1 mg/ml) were added to positive control wells, in addition, media only was added for negative control conditions. Cells were incubated at 37° C., 5% CO.sub.2 for 45 minutes. 10 ul Golgi Stop were added to each well, and cells were incubated for further 4 hours. For readout, cells were harvested, transferred to FACS tubes, washed twice with FACS buffer, and labelled with anti-CD56-BV-570 and near infrared dead cell marker. After 20 minutes incubation cells were washed, resuspended in fresh buffer, and run on the flow cytometer.

    NK Cell I FNγProduction:

    [0230] NK cells isolated from buffy coats of healthy volunteers were stimulated for 48hrs with 500 U/ml IL-2 in DMEM media containing 10% FBS. Cells were harvested, washed twice with PBS, resuspended at 1×10.sup.6 cells/ml in DMEM complete media. 100 ul cell suspension were seeded per well in 96-well plates. 20 ul of media were added to all samples, either containing media only (negative control), or aCD38-b-348, daratumumab or isotype control to reach a final concentration of 10mg/m1 in each test well. The positive control contained PMA/Ionomycin. The same conditions were set up for wells containing a co-culture of MDA-MB-231 tumour cells (100 000 cells/well) and NK cells (as above). GolgiPlug and GolgiStop were added to all wells (10 ul). Cells were incubated at 37° C., 5% CO.sub.2 for 6 hours. For readout, cells were harvested, washed, transferred to FACS tubes, stained with anti-CD56-FITC and Aqua Dead cell maker for 20 minutes. After wash with FACS buffer cells were fixed for 20 minutes with fixation buffer, permeabilised and stained with anti-IFNγ-APC for 30 minutes. Cells were washed and resuspended for readout at flow cytometer.

    NK Cell Proliferation:

    [0231] NK cells isolated from buffy coats of healthy volunteers were stimulated for 48hrs with 500 U/ml IL-2 in DMEM media containing 10% FBS. NK cells were harvested, washed, and labelled with CFSE proliferation dye: 8×10.sup.6 cells were resuspended in 1 ml PBS in a falcon tube. 110 ul PBS were added as 1 drop to the side of the tube held horizontally, 0.2 ul CFSE were added into the PBS drop. Tube was vortex to mix cell suspension and CSFE solution, and incubated for 20 minutes at 37° C., 5% CO.sub.2. 5 ml DMEM media were added, cells were further incubated for 5 minutes, spun down, washed, resuspended in complete media at 1x10.sup.6 cells/ml. 100 ul cell suspension was seeded per well in 96-well plates. MDA-MB-231 cells were added at a 50:1 ratio in 80 ul media per well. 20 ul media containing aCD38-b-348, daratumumab, or IgG1 isotype control were added to result in a final concentration of 0.4, 2, or 10 ug/ml. Cells were incubated for 6 days and proliferation was assessed by flow cytometry looking at dilution of proliferation dye CFSE in the NK cell population.

    Results

    [0232] Soluble aCD38-b-348 or daratumumab (10 ug/ml) increase degranulation of un-activated or IL2 pre-activated human NK cells (FIG. 20). Soluble aCD38-b-348 or daratumumab (10 ug/ml ) increase IFNy production of NK cells in the presence or absence of a tumour target (MDA-MB-231 cells), FIG. 21. Soluble aCD38-b-348 but not daratumumab increases proliferation of human NK cells, as compared to control, in the presence of MDA-MB-231 tumour cells (FIG. 22).

    [0233] The results show that soluble aCD38-b-348 antibody induces strong activation of primary human NK cells in vitro, defined by degranulation, IFNγ-production and proliferation. No further stimulation of NK cells is needed for these effects. Daratumumab induces similar NK cell degranulation and IFNγ-production, but no NK cell proliferation.

    Example 7: Antibody Binding to Mutant CD38

    [0234] Materials and Methods: Two mutant version of human CD38 were constructed. In one version D was mutated to G at position 202 (D202G) and in the second version S was mutated to F at position 274 (S274F).

    [0235] The binding of aCD38-b348 to each of the mutated CD38 proteins was assessed, and compared to daratumumab.

    Results

    [0236]

    TABLE-US-00020 TABLE 8 Binding Reactivity (% WT) Antibody Mutation-D202G Mutation-S274F aCD38-b348 Fab HS 66.8 (12) 106.1 (9) Daratumumab 39.9 (8) 6.8 (6)

    [0237] The results as provided in Table 8 show that binding of aCD38-b348 was not affected by the introduction of mutation D202G or mutation S274F into human CD38. This compares to Daratumumab where antibody binding was affected by the introduction of mutation S274F, but was not affected by the introduction of mutation D202G into human CD38. These results confirm that aCD38-b-348 binds to a different epitope than daratumumab.

    [0238] A summary of the sequences included in the application is provided below

    TABLE-US-00021 SEQ ID Description of antibody NO sequences Also referred to as 1 aCD38-b-348 variable heavy chain CD38-b-348-HCDR1 CDR1 2 aCD38-b-348 variable heavy chain aCD38-b-348-HCDR2 CDR2 3 aCD38-b-348 variable heavy chain aCD38-b-348-HCDR3 CDR3 4 aCD38-b-348 variable heavy chain aCD38-b-348-HCDR123 CDR 1, 2, 3 and FR 2, 3 aCD38-b-348-m1-HCDR123 aCD38-b-348-m2-HCDR123 aCD38-b-348-m3-HCDR123 aCD38-b-348-m4-HCDR123 5 aCD38-b-348 variable light chain aCD38-b-348-LCDR1 CDR1 6 aCD38-b-348 variable light chain aCD38-b-348-LCDR2 CDR2 7 aCD38-b-348 variable light chain aCD38-b-348-LCDR3 CDR3 8 aCD38-b-348 variable light chain aCD38-b-348-LCDR123 CDR 1, 2, 3 and FR 2, 3 9 Human CD38 Uniprot sequence P28907 10 aCD38-b-348-m1 variable light aCD38-b-348-m1-LCDR3 chain CDR3 11 aCD38-b-348-m2 variable light aCD38-b-348-m2-LCDR3 chain CDR3 12 aCD38-b-348-m3 variable light aCD38-b-348-m3-LCDR3 chain CDR3 13 aCD38-b-348-m4 variable light aCD38-b-348-m4-LCDR3 chain CDR3 14 aCD38-b-348 variable heavy aCD38-b-348-VH chain CDR 1, 2, 3 and FR 1, 2, aCD38-b-348-m1-VH 3, 4 aCD38-b-348-m2-VH aCD38-b-348-m3-VH aCD38-b-348-m4-VH 15 aCD38-b-348-m1 variable light aCD38-b-348-m1-VL chain CDR 1, 2, 3 and FR 1, 2, 3, 4 16 aCD38-b-348-m2 variable light aCD38-b-348-m2-VL chain CDR 1, 2, 3 and FR 1, 2, 3, 4 17 aCD38-b-348-m3 variable light aCD38-b-348-m3-VL chain CDR 1, 2, 3 and FR 1, 2, 3, 4 18 aCD38-b-348-m4 variable light aCD38-b-348-m4-VL chain CDR 1, 2, 3 and FR 1, 2, 3, 4 19 aCD38-b-348 variable light aCD38-b-348-VL chain CDR 1, 2, 3 and FR 1, 2, 3, 4 20 aCD38-b-348-m1 variable light aCD38-b-348-m1-LCDR123 chain CDR 1, 2, 3 and FR 2, 3 21 aCD38-b-348-m2 variable light aCD38-b-348-m2-LCDR123 chain CDR 1, 2, 3 and FR 2, 3 22 aCD38-b-348-m3 variable light aCD38-b-348-m3-LCDR123 chain CDR 1, 2, 3 and FR 2, 3 23 aCD38-b-348-m4 variable light aCD38-b-348-m4-LCDR123 chain CDR 1, 2, 3 and FR 2, 3 24 Daratumumab variable heavy chain 25 Daratumumab variable light chain

    EQUIVALENTS AND SCOPE

    [0239] Those skilled in the art will appreciate that the present invention is defined by the appended claims and not by the Examples or other description of certain embodiments included herein.

    [0240] Similarly, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

    [0241] Unless defined otherwise above, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. Generally, nomenclatures used in connection with, and techniques of, cell and tissue culture, molecular biology, immunology, genetics and protein and nucleic acid chemistry described herein are those well known and commonly used in the art, or according to manufacturer's specifications.

    [0242] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.

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