Kyverna shares surge 22.75% after-hours on positive SPS trial data, with miv-cel meeting endpoints and plans to file 2026 FDA approval.

Kyverna Therapeutics surged 22.75% in after-hours trading following the release of positive topline data from its registrational KYSA-8 trial of miv-cel (KYV-101) in stiff person syndrome (SPS). The Phase 2 trial met its primary endpoint, with a median 46% improvement in timed 25-foot walk tests and 81% of patients achieving clinically meaningful 20% gains. The therapy also eliminated the need for immunotherapies in all participants and demonstrated manageable safety. Kyverna announced plans to submit a Biologics License Application in early 2026, positioning miv-cel as a potential first-in-class CAR-T therapy for autoimmune diseases. The results, described as a "best-case scenario" by analysts, underscore the treatment’s potential to address a high-unmet-need condition with no approved therapies, driving significant investor optimism.