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 non-secretory multiple myeloma, plasma cell leukemia, Waldenstrom's
             macroglobulinemia, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal
             protein, and skin changes) syndrome, or amyloidosis.

          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. Subject has received prior therapy directed at B cell maturation antigen (BCMA).

          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. Subject has inadequate pulmonary function.

         20. Subject has active, uncontrolled, or suspected infection.

         21. Subject has pulmonary, cardiac, or hepatic involvement of extramedullary multiple
             myeloma.

         22. Subjects with a history of severe allergic or anaphylactic reactions or
             hypersensitivity to excipients in the investigational product.

         23. Recent SARS-CoV-2 vaccine as specified in the protocol.