Safety and efficacy of B cell maturation antigen‐directed CAR T‐cell therapy in patients with relapsed/refractory multiple myeloma and concurrent light chain amyloidosis

Abstract Clinical trials evaluating chimeric antigen receptor (CAR) T‐cell therapy in relapsed/refractory multiple myeloma (RRMM) have typically excluded patients with AL amyloidosis. As a result, there are limited data on the safety and efficacy of CAR T‐cell therapy in this patient population. We retrospectively reviewed eight consecutive patients with RRMM and AL amyloidosis who were treated with standard of care CAR T‐cell therapy. Cytokine release syndrome was seen in 75% of patients (grade ≥3: 0%) and immune effector cell‐associated neurotoxicity syndrome (grade 1) in only one patient. Low‐grade cytopenias were common (any grade/grade ≥3: neutropenia 62.5%/37.5%, anemia 37.5%/0%, thrombocytopenia 25%/0%). CAR T‐cell therapy led to rapid and deep responses with a median time to best response of 43 days and a hematologic very good partial response or better rate of 62.5%. Overall, we found that commercial CAR T‐cell therapy was feasible, and effective in patients with RRMM and concurrent AL amyloidosis.