Single-arm SPS trial met all endpoints; BLA filed on that data alone — approval hinges on FDA accepting it without a randomized control

Kyverna Therapeutics is a clinical-stage biopharmaceutical company developing miv-cel, a cell therapy for stiff person syndrome, a rare neurological disorder causing progressive rigidity; the therapy is not yet approved and its regulatory path depends on FDA acceptance of single-arm trial data in place of a traditional randomized controlled trial.

Kyverna's miv-cel, a CD19-targeting CAR-T designed to reset autoreactive B cells, posted statistically significant improvements across all primary and secondary endpoints in KYSA-8, a 26-patient single-arm trial in stiff person syndrome, a rare neurological disease causing progressive rigidity and disability. The thesis resolves on whether FDA accepts that single-arm package for approval, with RMAT designation enabling rolling review and priority consideration. The core approval risk is the absence of a randomized control arm, a structural vulnerability the agency could revisit despite pre-BLA alignment on endpoints.