Anti-BCMA CAR-T therapy in patients with progressive multiple sclerosis.

Progressive multiple sclerosis (PMS), which is characterized by relentless disease progression, lacks effective treatment. While recent studies have highlighted the importance of B cells in driving compartmentalized central nervous system (CNS) inflammation in PMS pathogenesis, current B cell depletion therapies, such as CD20 monoclonal antibodies, face challenges in targeting plasma cells within the CNS. Here, we treated five patients with PMS (one primary PMS and four secondary PMS) with anti-B cell maturation antigen (BCMA) chimeric antigen receptor T (CAR-T) cell therapy in an ongoing phase 1 clinical trial (ClinicalTrials.gov: NCT04561557). Only grade 1 cytokine release syndrome was observed, and all grade ≥3 cytopenias occurred within 40 days post-infusion in all five patients. Meanwhile, we detected plasma cell depletion in CNS compartments, prolonged expansion and relieved exhaustion of CAR-T cells in the cerebrospinal fluid, and attenuation of microglial activation. These findings provided insights into the potential application of anti-BCMA CAR-T therapy for advancing clinical management of PMS.