The Safety of Bridging Radiation with Anti-BCMA CAR T-Cell Therapy for Multiple Myeloma

Purpose: B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor (CAR) T cells (CART-BCMA) are a promising treatment for relapsed/refractory multiple myeloma (r/rMM). We evaluated the safety and feasibility of bridging radiation (RT) in subjects treated on a phase I trial of CART-BCMA. Experimental Design: Twenty-five r/rMM subjects were treated in three cohorts with two doses of CART-BCMA cells ± cyclophosphamide. We retrospectively analyzed toxicity, response, and CART manufacturing data based on RT receipt. Results: Thirteen subjects received no RT Conclusions: Bridging-RT appeared safe and feasible with CART-BCMA therapy in our r/rMM patients, though larger future studies are needed to draw definitive conclusions.