Radiation therapy as a bridging and salvage strategy in patients with relapsed or refractory multiple myeloma undergoing BCMA-targeted CAR T-cell therapy.

Radiation therapy (RT) may play an important role prior to and following BCMA-targeted CAR T-cell therapy in multiple myeloma (MM). We report a series of 13 patients: 5 patients received bridging RT pre-CAR T, 4 patients received salvage RT post-CAR T failure, and 4 patients received both. There was no worsening of CAR-T- or RT-related toxicities. The RT in-field local control rate was 100%, with a median follow-up after each RT course of 7.3 months. RT as a bridging and salvage strategy is safe, feasible, and offers excellent local control in MM patients treated with CAR T-cell therapy.