ABSTRACT
Background: Chimeric antigen receptor T cells (CART) have shown promising results in the treatment of relapsed and refractory multiple myeloma (RRMM). Recently, bispecific-CART cells targeting 2 antigens are being evaluated in various clinical trials. Methods: A comprehensive literature search was done of Pubmed, Embase, and Cochrane. Data presented at annual hematology and oncology conferences were also included. Results: We included 4 phase I clinical trials with a total of 77 RRMM patients between the ages of 18 to 71 years. The median follow-up duration ranged from 1 month to 27.5 months. All were lymphodepleted with Cyclophosphamide and Fludarabine before receiving CAR-T cell therapy. The CAR-T cell targets include BCMA and CD38 (dose range 0.5 x 10∧6 - 4 x 10∧6 cells/kg), BCMA and TACI (dose range 15 - 900 x 10e6 CAR-T cells), BCMA and CD19 (1 x 10e5/kg - 3 x 10e5 CAR-T cells/kg), and BCMA and CD19 (dose 1 x 10e6 cells/kg). Overall response rate (ORR) was reported by 4 trials (87.5%, 43%, 93.8%, 95%). Complete response (CR) was also reported in 4 trials as 50%, 64%, 56.3% and 14% and partial response (PR) reported as 25%, 28%, 16.6%, 14%, 18% in 5 trials (table). The most common grade 3-4 adverse effects that were reported include cytokine release syndrome, neurotoxicity, neutropenia, lymphopenia, anemia, thrombocytopenia, diarrhea, increased LDH, lower respiratory tract infections (LRTI), dehydration, renal failure (table). Yan et al. reported one death due to cerebral hemorrhage which was considered unrelated to treatment. Jiang et al. reported one death from unknown cause of a patient who presented with fever during the COVID- 19 pandemic.Conclusions: Bispecific CART cells have shown promising results in the treatment of RRMM. However, the clinical trials are ongoing, and a longer follow-up is needed.