Clinical Study on Evaluating the Safety and Effectiveness of BCMA-GPRC5D CAR-T in Patients With Relapsed/Refractory Multiple Myeloma Who Have Received Third-line or Above Treatment

The entire study process was as follows: Screening period (V1) : Informed consent was signed, screening was checked, criteria were evaluated, and baseline demographic information and subject status were recorded. Blood collection period (V2) : For subjects who meet the inclusion and exclusion criteria, the blood required for CAR-T preparation will be obtained by leukocyte isolation monopexy or intravenous collection according to the conditions of the subjects. Preconditioning phase (V3) : cytokine and cell changes. Pre-transfusion assessment (V4) : The investigator assessed that the test results met the cell transfusion criteria, and D0 CAR T cell infusion could be performed with investigator permission. Infusion phase (V5) : CAR-T cells were transfused according to the dosage and method specified in the protocol. Safety and efficacy were followed up on D1, D4, D7, D10, D14, D21, D28, M3, M6, M9, M12, and M24.