Inclusion Criteria:

- Documented diagnosis of multiple myeloma with measurable disease (serum, urine, or free light chain) per International Myeloma Working Group (IMWG) criteria, including non-secretory or oligo-secretory multiple myeloma which has relapsed after or is refractory to prior therapies, including proteasome inhibitors (PIs), immunomodulators
(IMiDs) and anti-CD38 targeted therapies (daratumumab, isatuximab).

- Eastern Cooperative Oncology Group (ECOG) performance-status score of 2 or less and 1 or less (for France).

- Adequate hematologic, renal, and hepatic functions

- Seronegative for hepatitis B antigen; positive hepatitis B tests can be further evaluated by confirmatory tests, and if viral load is negative, the subject can be enrolled.

- Seronegative for hepatitis C antibody; if positive, then further test for the presence of antigen by hepatitis C virus polymerase chain reaction (HCV PCR). If HCV antigen
tests are negative, then the subject can be enrolled.

- Oxygen saturation level ≥92% on room air.

- Left ventricular ejection fraction (LVEF) ≥ 50% and no pericardial or pleural effusion at Screening.

• - Recovered from acute effects of any prior therapy or previous surgery and no history of major surgery within 28 days prior to start of study drug. Vertebroplasty and kyphoplasty are not considered major surgery. Note: Recovery is defined as NCI CTCAE v5 Grade ≤ 1 except for:
  • Adverse events not constituting a safety risk by Investigator judgement;
  • Peripheral neuropathy attributable to bortezomib in the limit of Grade ≤ 2.

Exclusion Criteria:

- Active central nervous system involvement.

- Exposure to daratumumab or isatuximab within 2 months prior to the start of study treatment.

- Active plasma cell leukemia.

- Active infectious disease.

- Clinically significant cardiovascular and respiratory conditions.

- History of HIV infection.

- Subjects requiring prohibited concomitant medications.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 9/26/23. Questions regarding updates should be directed to the study team contact.