Kyverna says one-year CAR-T data strengthen FDA filing for stiff-person syndrome

Kyverna Therapeutics reported one-year data for mivocabtagene autoleucel (miv-cel), its experimental CAR-T therapy for stiff-person syndrome (SPS), showing sustained clinical benefit in all 26 patients in the registrational Phase 2 KYSA-8 trial.

Median improvement on the timed 25-foot walk test increased from 46% at 16 weeks to 49% at 12 months, according to the company.

The therapy maintained a favorable safety profile:
no cases of high-grade cytokine-release syndrome, ICANS, or IEC-HS were reported in the update.

Kyverna plans to add the long-term data to its rolling biologics license application (BLA) to the FDA. The company expects to complete the submission in the fourth quarter of 2026 and is seeking priority review under its RMAT designation.

If approved, miv-cel could become the first FDA-approved CAR-T therapy for an autoimmune disease. Kyverna also reported durable improvements in early follow-up from its generalized myasthenia gravis program.