The purpose of this study is to establish a safe and tolerable dose of arlocabtagene autoleucel (BMS-986393) in combinations with alnuctamab, mezigdomide, iberdomide, and elranatamab in participants with relapsed and/or refractory multiple myeloma (RRMM).

Inclusion Criteria:

• History of relapsed and/or refractory multiple myeloma (RRMM) treated with at least 3 (Part 1) or at least 1 but not greater than 3 prior anti-myeloma treatment regimens (Part 2).
• Measurable multiple myeloma (MM) as per International Myeloma Working Group (IMWG).
• Eastern Cooperative Oncology Group performance status of 0-1.

Exclusion Criteria:

• Prior treatment with alnuctamab (Arm A), mezigdomide (Arm B), iberdomide (Arm C), elranatamab (Arm D) or BCMA-targeting therapy (Part 2 Arms A and D).
• Prior treatment with GPRC5D-targeting therapies.
• Other protocol-defined inclusion/exclusion criteria apply.

BMS will provide access to individual anonymized participant data upon request from qualified researchers, and subject to certain criteria. Additional information regarding Bristol Myer Squibb's data sharing policy and process can be found at: https://www.bms.com/researchers-and-partners/clinical-trials-and-research/disclosurecommitment.html