Sponsor: Bristol-Myers Squibb

Key Inclusion Criteria:

• Participant has documented diagnosis of multiple myeloma and measurable disease, defined as any of the following:
• Myeloma-protein (M-protein) ≥ 0.5 grams/deciliter (g/dL) by serum protein electrophoresis (sPEP), or
• M-protein ≥ 200 milligrams (mg)/24-hour urine collection by urine protein electrophoresis (uPEP) or,
• For participants without measurable disease in sPEP or uPEP: serum free light chain levels > 100 mg/liter (L) (10 mg/dL) involved light chain and an abnormal κ/λ free light chain ratio.
• Participant has received at least one prior line of anti-myeloma therapy.
• Participant must have received prior treatment with lenalidomide and at least 2 cycles of an anti-CD38 monoclonal antibody.
• Participant achieved minimal response or better to at least 1 prior anti-myeloma therapy.
• Participant must have documented disease progression during or after their last antimyeloma regimen.
• Additional protocol-defined criteria apply.

Key Exclusion Criteria:

• Participant who has had prior treatment with CC-92480 or carfilzomib.
• Participant has previously received allogeneic stem cell transplant at any time or received autologous stem cell transplant within 12 weeks of initiating study treatment.

Additional protocol-defined criteria apply.

Primary Outcome Measures:

1. Progression-free Survival (PFS)

Secondary Outcome Measures:

1. Recommended CC-92480 Dose (Stage 1 only)
2. Overall Survival (OS)
3. Overall Response Rate (ORR)
4. Rate Of Very Good Partial Response (VGPR) Or Better (VGPRR)
5. Rate Of Complete Response (CR) Or Better (CRR)
6. Time To Response (TTR)
7. Duration Of Response (DOR)
8. Time To Progression (TTP)
9. Time To Next Treatment (TTNT)
10. Progression-free Survival 2 (PFS-2)
11. Minimal Residual Disease (MRD) Negativity Rate
12. Number Of Participants With Adverse Events (AEs)

13.   Mean Change from baseline in the European Organization for Research and Treatment of Cancer - Quality of Life C30 Questionnaire (EORTC QLQ-C30) Health Related Quality of Life Scores. The EORTC QLQ-C30 is the most commonly used quality of life instrument in oncology trials. The QLQ-C30 consists of 30 questions incorporated into the physical, role, cognitive, emotional, and social domains. It will also include an assessment of symptoms such as fatigue, pain, nausea and vomiting, dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties. Additionally, a single global Quality of Life (QoL)/global health status score will be collected. (Stage 2 only).

14.  Mean change from baseline in the European Quality of Life Multiple Myeloma Module (EORTC QLQ-MY20). The EORTC QLQ-MY20 is a 20-item myeloma module intended for use among participants varying in disease stage and treatment modality. (Stage 2 only).

Study Locations in Europe: Austria, Denmark, Germany, Greece, Hungary, Italy, Netherlands, Norway, Spain, United Kingdom.

Estimated Study Completion Date: February 2026

Further information on clinicaltrial.gov - trial number NCT05552976