Researchers at Charité—Universitätsmedizin Berlin reported early clinical-trial evidence that CD19 CAR T-cell therapy (mivocabtagene autoleucel) can bring severe, treatment-refractory seropositive rheumatoid arthritis into remission in a small Phase 1 cohort. The COMPARE study enrolled six patients after stopping disease-modifying antirheumatic drugs and standard lymphodepletion. The team reported marked reductions in disease activity across all participants, with three patients entering sustained remission without ongoing medication during follow-up through roughly one year. The results are framed as particularly striking given the patients’ history of inadequate response to multiple established targeted or biologic therapies. For CAR T developers and autoimmune immunologists, the work represents a proof-of-concept step for extending cell-based oncology platforms into durable autoimmune disease control, albeit with the need for larger controlled studies to establish durability and risk-benefit profile.