A Modular, Phase I/II, Open-label, Multicentre Study to Evaluate the Safety, Tolerability, Cellular Kinetics, and Efficacy of AZD4045, an Allogeneic Chimeric Antigen Receptor-T Cell (CAR-T) Therapy Targeting B Cell Maturation Antigen (BCMA) in Participants With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Participant must be 18 years or older at the time of signing the informed consent form. * Participants must have documented diagnosis of MM according to the IMWG diagnostic criteria. * Participant must have one or more of the following measurable disease criteria: * Serum M-protein level ≥ 1.0 g/dL. * Urine M-protein ≥ 200 mg/24 h. * Serum immunoglobulin free light chain ≥ 10 mg/dL (100 mg/L) and abnormal serum immunoglobulin kappa lambda free light chain ratio. * ECOG performance score of 0 to 1. * Participant must have screening bone marrow aspirate and/or archi…