A Phase 1, Open-label, Dose Finding Study of CC-93269, a BCMA X CD3 T Cell Engaging Antibody, in Subjects With Relapsed and Refractory Multiple Myeloma.

The dose escalation part (Part A) of the study will evaluate the safety and tolerability of escalating doses of CC-93269, administered intravenously (IV), to determine the MTD and NTD of both the first dose and subsequent doses of CC-93269. The expansion part (Part B) will further evaluate the safety and efficacy of CC-93269 administered IV at or below the MTD in selected expansion cohorts of up to approximately 20 evaluable subjects each in order to determine the RP2D. CC-93269, administered IV followed by subcutaneously (SC), will also be evaluated (Part C). One or more dosing regimens may be selected for cohort expansion. All treatments will be administered in 28-day cycles for up to 2 years until confirmed disease progression, unacceptable toxicity, or subject/Investigator decision to withdraw.

Inclusion Criteria:

Subjects must satisfy the following criteria to be enrolled in the study:

1. Subject must understand and voluntarily sign an informed consent form (ICF) prior to any study-related assessments/procedures being conducted.
2. Subject (male or female) is ≥ 18 years of age the time of signing the ICF.
3. Subject has a history of Multiple Myeloma (MM) with relapsed and refractory disease, and must have failed treatment with, are intolerant to or are not candidates for available therapies that are known to confer clinical benefit to patients with relapsed and refractory MM.
4. Subjects must have measurable disease (as determined by the central lab).
5. Subject consents to hospitalization for monitoring and collection of study peripheral blood samples.
6. Subject consents to serial bone marrow aspirations and/or biopsies during Screening, study treatment and at the end of treatment.
7. Subject has an Eastern Cooperative Oncology Group (ECOG) PS of 0 or 1.
8. Subjects must have adequate hematologic, liver, renal, and coagulation function as assessed by laboratory tests.
9. Females and males must practice true abstinence or agree to contraceptive methods throughout the study, and during the safety follow-up period.

Exclusion Criteria:

The presence of any of the following will exclude a subject from enrollment:

1. Unless otherwise specified, Subject has received prior investigational therapy directed at B cell maturation antigen (BCMA). In selected cohort(s) of Parts A and B, prior therapy directed at BCMA may be required for enrollment
2. Subject has symptomatic central nervous system involvement of multiple myeloma.
3. Subject has non-secretory multiple myeloma, plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes), or amyloidosis.
4. Subject is on chronic systemic immunosuppressive therapy or corticosteroids.
5. Subjects with clinically significant cardiac disease.
6. Subject had a prior autologous stem cell transplant ≤ 3 month prior to starting CC-93269.
7. Subject had a prior allogeneic stem cell transplant ≤ 12 month prior to starting CC-93269.
8. Subject had a prior systemic cancer-directed treatments or investigational modalities ≤ 5 half-lives or 4 weeks prior to starting CC-93269, whichever is shorter. Subjects must have recovered from any clinically significant non-hematologic toxicities (ie, to Grade ≤1) of prior systemic anti-cancer directed treatments unless otherwise specified
9. Subject had major surgery ≤ 2 weeks prior to starting CC-93269.
10. Subject is a pregnant or lactating female.
11. Subject has known history or serologic evidence of human immunodeficiency virus (HIV) infection.
12. Subject has known history, virologic or serological evidence of hepatitis B or C virus (HBV/HCV) infection. Subjects who had HCV but have received an antiviral treatment and show no detectable HCV viral RNA for 6 months are eligible
13. Subject has a history of a venous thromboembolic event (VTE) within 6 months prior to study entry (eg, deep-vein thrombosis or pulmonary embolism). Subjects with distant history of VTE (ie, occurring > 6 months prior to study entry) who require ongoing treatment with chronic, therapeutic dosing of anti-coagulants (eg, warfarin, low molecular weight heparin, Factor Xa inhibitors) are eligible for study entry.
14. Subject has a history of concurrent second cancers requiring active, ongoing systemic treatment.
15. Subject has a history or presence of clinically relevant central nervous system (CNS) pathology.
16. Subject has any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from participating in the study.
17. Subject has any condition (eg, active or uncontrolled infection) including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study. .
18. Subject has any condition that confounds the ability to interpret data from the study.
19. Inadequate pulmonary function.
20. Subject has active, uncontrolled, or suspected infection.