Key Inclusion Criteria:

• Documented historical diagnosis of multiple myeloma (MM)
• Received 1 to 3 prior lines of antimyeloma therapy, including an immunomodulatory drug (IMiD) and an anti-cluster of differentiation 38 (CD38) monoclonal antibody (mAb). A minimum of 2 consecutive cycles of an IMiD and an anti-CD38 mAb in any prior line of therapy is required. The IMiD and anti-CD38 mAb do not need to be from the same regimen in the prior line(s) of therapy.
• Documented evidence of progressive disease by IMWG criteria based on the investigator's determination on or within 12 months of the last dose of the last regimen
• Measurable disease at screening per IMWG, defined as any of the following:
  • Serum M-protein level ≥ 0.5 g/dL or urine M-protein level ≥ 200 mg/24 hours; or
  • Light chain MM without measurable disease in the serum or urine: serum free light chain ≥ 10 mg/dL and abnormal serum free light chain ratio
• Only individuals who are candidates to receive at least 1 of the 4 SOCT regimens (PVd, DPd, KDd, or Kd), as determined by the investigator, should be considered for this study
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Females of childbearing potential must have a negative serum or urine pregnancy test with a sensitivity of at least 25 mIU/mL (females who have undergone surgical sterilization or who have been postmenopausal for at least 2 years are not considered to be of childbearing potential)

Key Exclusion Criteria:

• Prior B-cell maturation antigen (BCMA)-targeted therapy
• Prior T-cell engager therapy
• Prior CAR therapy or other genetically modified T-cell therapy
• Active or prior history of central nervous system (CNS) or meningeal involvement of MM
• Cardiac atrial or cardiac ventricular MM involvement
• History of or active plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes), or amyloidosis
• Active malignancy (other than MM) requiring ongoing treatment for disease control within the last 24 months. Myelodysplastic syndrome (even without ongoing treatment) is not permitted.
• Prior auto-SCT within 12 weeks before randomization
• Prior allogeneic stem cell transplant (allo-SCT)
• High-dose (eg, cumulative > 70 mg prednisone or equivalent) systemic steroid therapy or any other form of immunosuppressive therapy within 14 days before randomization
• Live vaccine ≤ 4 weeks before randomization
• Contraindication to fludarabine or cyclophosphamide
• History of allergy or hypersensitivity to any study agent or study drug components. Individuals with a history of severe hypersensitivity reaction to dimethyl sulfoxide (DMSO) are excluded.
• Life expectancy < 12 weeks