HR-003

Primary study objectives: To evaluate the efficacy of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. Secondary study objectives: (1) To evaluate the safety of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. (2) To evaluate the pharmacokinetics of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. (3) To evaluate the pharmacodynamics of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. (4) To evaluate the immunogenicity of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. (5) To evaluate other efficacy indicators of anti-human BCMA T cell injection in the treatment of relapsed/refractory multiple myeloma subjects. Exploratory study objectives: (1) To explore the distribution of anti-human BCMA T cells in the subjects and the changes in the immune phenotype in the peripheral blood after reinfusion; (2) To explore the pharmacodynamic indicators in pleural effusion, peritoneal effusion, cerebrospinal fluid, etc.; (3) To explore the serum organ damage indicators and redox status after reinfusion of anti-human BCMA T cells.