Bristol Myers Squibb disclosed that one patient died following treatment with its investigational autoimmune CAR-T therapy in a Phase 1 trial in multiple sclerosis. The company said the patient developed motor symptoms not resolved with standard autoimmune treatments, then received an immunosuppressant and subsequently developed septic pneumonia. The disclosure comes amid heightened scrutiny of safety signals in autoimmune CAR-T studies, including earlier pauses and safety-related updates from peers in the category. BMS previously paused aspects of its autoimmune CAR-T program after observing transient inflammatory events during routine surveillance. For the CAR-T field, the reported event reinforces the ongoing risk-management challenge of autoimmune-targeting cell therapies—where immune dysregulation can be both the mechanism and a safety vulnerability. Investigators will need continued transparency around adverse event characterization, management protocols, and monitoring triggers.