Documented evidence of PD by IMWG 2016 criteria based on investigator's determination during or after the most recent line of therapy.
Participants with only 1 prior line of therapy must have progressed within 47 months of a stem cell transplant, or if not transplanted, then within 42 months of starting initial therapy.
Received 1 to 3 lines of prior therapy including an IMiD and either a PI or a CD38 antibody.
Participant must have undergone at least 2 complete cycles of treatment for each line of therapy, unless PD was the best response to the line of therapy.
Eligible to receive at least one of the standard regimens (DKd, PVd, DPd, or Kd) as determined by the Investigator.
ECOG performance status score of 0 to 1.
Adequate hematology and chemistry laboratory values.
Haemoglobin ≥ 8.0 g/dL.
Absolute neutrophil count ≥ 1 × 10^9/L (1000 per mm3).
Platelet count ≥ 75 × 10^9/L (75000 per mm3) in participants with < 50% of bone marrow nucleated cells are plasma cells or ≥ 50 × 10^9/L (50000 per mm3) in participants with ≥ 50% of bone marrow nucleated cells are plasma cells.
Absolute lymphocyte count ≥ 300/µL (0.3 × 109/L).
Total bilirubin ≤ 1.5 × ULN in the absence of Gilbert's syndrome or ≤ 3 × ULN if the participant has Gilbert's syndrome.
AST and ALT ≤ 3.0 × ULN.
CrCl by Cockcroft and Gault method ≥ 30 mL/minute.
Known active, or prior history of CNS involvement or exhibits clinical signs of meningeal involvement of MM.
Primary amyloidosis, active plasma cell leukaemia, Waldenstrom macroglobulinemia or Polyneuropathy Organomegaly Endocrinopathy M-protein and Skin (POEMS) syndrome.
Participants with primary refractory MM failed to generate at least a minimal response to any prior therapy.
Significant neurological or psychiatric condition.
Significant medical condition that places the participant at an unacceptable risk for treatment-related complications.
Previously received any prior BCMA-targeted treatment.
Previously received CAR-T or CAR-NK therapy directed at any target.
Previously received T-cell engager therapy directed at any target.
Previously received allogeneic stem cell transplantation at any time during prior therapy or received autologous stem cell transplantation within 12 weeks of randomization.