Methods Autologous peripheral blood lymphocytes were collected from patients, who subsequently underwent intravenous fludarabine (30mg/m2/d) and cyclophosphamide (300mg/m2/d) lymphodepletion chemotherapy from day-5 to day -3. Conclusions The clinical trial demonstrated that BCMA CAR-T therapy, composed of dual nanobody VHHs targeting BCMA (dVHHs), exhibits a high ORR with a manageable safety profile in treating R/R MM patients. This extends even to high-risk patients, such as those with extramedullary lesions, cytogenetics high-risk groups, and patients with plasma cell leukemia or anaplastic plasma cell tumor.