Inclusion Criteria:

• Age ≥ 18 years at the time of informed consent.
• Subjects must understand and voluntarily sign written informed consent obtained prior to any study procedure/assessment being conducted.
• Willing and able to adhere to the study visit schedule and other protocol requirements.
• Diagnosis of relapsed and/or refractory multiple myeloma (MM). Subjects must have received at least 3 prior antimyeloma treatment regimens (note: induction with or without bone marrow transplant and with or without maintenance therapy is considered one regimen). Subject must be refractory to the last treatment regimen prior to study entry. Refractory myeloma is defined as documented progressive disease during or within 60 days (measured from the last dose) of completing treatment with the last anti-myeloma treatment regimen before study entry. Subjects must have previously received all of the following therapies:
  • Autologous stem cell transplant (ASCT). Subjects who were not candidates to receive ASCT treatment (due to age or other factors) are eligible; the reason for not receiving ASCT must be documented in the electronic case report form (eCRF).
  • A regimen that included an immunomodulatory agent (e.g., thalidomide, lenalidomide, pomalidomide) and a proteasome inhibitor (e.g., bortezomib, carfilzomib, ixazomib), either alone or in combination. Subjects must have undergone at least 2 consecutive cycles of treatment for each regimen unless progressive disease was the best response to the regimen;
  • Anti-CD38 (e.g., daratumumab) as part of a combination regimen or as a monotherapy.
• Additional Inclusion Criteria may apply.

Exclusion Criteria:

• Uncontrolled medical, psychological, familial, sociological, or geographical conditions that do not permit compliance with the protocol, as judged by the Investigator; or unwillingness or inability to follow the procedures required in the protocol.
• Any condition including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study.
• Any condition that confounds the ability to interpret data from the study. Known active or history of central nervous system (CNS) involvement of MM.
• Active or history of plasma cell leukemia, Waldenstrom’s macroglobulinemia, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome, or clinically significant amyloidosis.
• Any prior CAR T-cell or another genetically modified T-cell therapy.
• Subject has received prior investigational therapy directed at BCMA including, but not limited to, bispecific T cell-engaging antibodies or molecules, antibody-drug conjugates (BCMA-ADC), or BCMA-directed T- cell therapy (e.g., BCMA chimeric antigen receptor (CAR) T cells).
• Additional Exclusion Criteria may apply.