Autologous T cells are genetically modified to express a high‑affinity BCMA‑directed chimeric antigen receptor with CD3ζ signaling and costimulatory domains. Upon binding BCMA on malignant plasma/B‑lineage cells, the CAR activates T‑cell effector functions, leading to proliferation, cytokine release, and cytotoxic killing of BCMA‑expressing tumor cells. Administered after lymphodepleting chemotherapy to promote in vivo expansion and persistence.