A Study to Determine the Recommended Dose and Schedule, and Evaluate the Safety and Preliminary Efficacy of Mezigdomide in Combination With Elranatamab in Participants With Relapsed and/or Refractory Multiple Myeloma

• Elranatamab (Drug), also known as Elrexfio, PF-0686313: Specified dose on specified days
• Mezigdomide (Drug), also known as BMS-986348, CC-92480: Specified dose on specified days
• Dexamethasone (Drug), also known as Decadron®: Specified dose on specified days

Primary outcomes

• Number of participants with Adverse Events (AEs) [From first participant first visit until 28 days after the last mezigdomide dose or 90 days after last elranatamab dose, whichever is longer]
• Number of participants with Serious AEs [From first participant first visit until 28 days after the last mezigdomide dose or 90 days after last elranatamab dose, whichever is longer]
• Number of participants with AEs meeting protocol-defined DLT criteria [From first participant first visit until 28 days after the last mezigdomide dose or 90 days after last elranatamab dose, whichever is longer]
• Number of participants with AEs leading to discontinuation [From first participant first visit until 28 days after the last mezigdomide dose or 90 days after last elranatamab dose, whichever is longer]
• Number of deaths [From first participant first visit until 28 days after the last mezigdomide dose or 90 days after last elranatamab dose, whichever is longer]
• Recommended Phase 2 Dose (RP2D) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]

Secondary outcomes

• International Myeloma Working Group (IMWG) Uniform Response Criteria: Overall Response Rate (ORR) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Complete Response Rate (CRR) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Very Good Partial Response Rate (VGPRR) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Time to Response (TTR) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Duration of Response (DOR) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Progression-free Survival (PFS) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• IMWG Uniform Response Criteria: Overall Survival (OS) [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]
• Number of participants who achieve minimal residual disease (MRD) negativity [From first participant enrollment until the last participant is no longer evaluable for response or has progressed or the last survival follow-up (At approximately 5 years)]: Defined as less than 1 in 10\^5 nucleated cells in BMA for participants who achieve CR or better at any time after enrollment

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Age ≥18 with history of relapsed and refractory multiple myeloma (RRMM) treated with 2 to 4 prior lines of anti-myeloma therapy (Phase 1) or 1 to 3 prior lines of anti-myeloma therapy (Phase 2).
* Measurable MM by local laboratory.
* Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 to 1.
* Adherence to contraception requirements.

Exclusion Criteria:

* Prior treatment with mezigdomide.
* Prior treatment with T cell engaging or T cell engager (TCE).
* Prior treatment with B cell-maturation antigen (BCMA)-targeting therapy, with the exception of participants who have received autologous BCMA-targeted CART-cell therapy> 6 months from the start of study therapy
* Other protocol-defined Inclusion/Exclusion criteria apply.

• Bristol-Myers Squibb, Study director, Bristol-Myers Squibb

NIH grants: 2025