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 | Arctuva