1. Adult male or female, at least 18 years old.
   
   
2. Eastern Cooperative Oncology Group (ECOG) performance of ≤ 2.
   
   
3. Subjects must have confirmed diagnosis of R/R MM with documented evidence of progression during or after the subject’s last treatment regimen based on the investigator’s determination of the IMWG criteria:
   
   • Relapsed defined as previously treated myeloma that progresses and requires initiation of salvage therapy, but does not meet criteria for refractory myeloma
   
   • Refractory defined as disease that is nonresponsive (failure to achieve minimal response [MR] or development of progressive disease) while on primary or salvage therapy, or progresses within 60 days of last therapy

1. History of other active malignancies, including myelodysplastic syndrome within the past 3 years with the following exceptions:

• Adequately treated in situ carcinoma of the cervix uteri or the breast;
• Basal cell carcinoma of the skin or localized squamous cell carcinoma of the skin;
• Prostate cancer Gleason grade 6 or lower AND with stable Prostate Specific Antigen levels off treatment;
• Previous malignancy with no evidence of disease confined and surgically resected (or treated with other modalities) with curative intent and unlikely to impact survival during the duration of the study.

2. Evidence of an active Hepatitis B, Hepatitis C or human immunodeficiency virus infection.

3. Evidence of an active, severe SARS-CoV-2 infection.

Additional study criteria will apply.