Kyverna Therapeutics reports one-year durability data for autoimmune cell therapy

Kyverna Therapeutics reports positive one-year durability data for its CAR T cell therapy, mivocabtagene autoleucel, in 26 patients with stiff person syndrome. The Phase 2 KYSA-8 trial met its primary endpoints, showing a 49% median mobility improvement at 12 months and allowing 67% of baseline walking-aid users to walk unassisted. These results bolster Kyverna's plans to complete a rolling FDA Biologics License Application by late 2026, positioning it ahead of competitors like Novartis and Bristol Myers Squibb, who recently paused trials due to safety concerns.

One-year durability of KYSA-8 trial

• ▪In the KYSA-8 trial, 24 of 26 patients with stiff person syndrome remained off protocol-defined immunotherapies through one year of follow-up after receiving mivocabtagene autoleucel.
• ▪Kyverna Therapeutics reported positive one-year follow-up durability data on September 24, 2026, from its Phase 2 KYSA-8 trial evaluating mivocabtagene autoleucel in 26 patients with stiff person syndrome.

Mobility improvements in the KYSA-8 trial

• ▪Kyverna Therapeutics reported that 95% of the KYSA-8 trial patients who initially achieved a 20% or greater mobility improvement retained that benefit at the one-year follow-up.
• ▪In the KYSA-8 trial, stiff person syndrome patients achieved a 49% median T25FW mobility improvement from baseline at 12 months, compared to a 46% improvement at Week 16.
• ▪Of the 12 stiff person syndrome patients in the KYSA-8 trial who required a walking aid at baseline, eight patients (67%) no longer needed assistance at one year.

Regulatory plans for mivocabtagene autoleucel

• ▪Kyverna Therapeutics is seeking priority review from the FDA for its mivocabtagene autoleucel Biologics License Application, according to Kyverna Therapeutics CEO Warner Biddle.
• ▪Kyverna Therapeutics is on track to complete a rolling Biologics License Application submission to the FDA for mivocabtagene autoleucel in stiff person syndrome in the fourth quarter of 2026.

Market and analyst reaction

• ▪H.C. Wainwright reiterated a Buy rating and a $25 price target on Kyverna Therapeutics stock following the release of the one-year KYSA-8 trial follow-up data.
• ▪Kyverna Therapeutics shares rose more than 7% to $7.55 in premarket trading on September 24, 2026, following the announcement of the one-year durability data.

Competitor CAR T trial pauses

• ▪Novartis paused several immunology and neurology studies of its CAR T candidate rap-cel after three patients suffered fatal cases of immune effector cell-associated hemophagocytic syndrome.
• ▪Bristol Myers Squibb voluntarily froze autoimmune trials for its CAR T therapy zolacabtagene autoleucel after observing transient and reversible inflammatory events.

Debatable claims

• ▪The clinical benefits of CAR T therapies for autoimmune diseases outweigh their safety risks
• ▪Recent safety failures in autoimmune CAR T trials are candidate-specific rather than class-wide
• ▪The complexity of CAR T therapies makes them impractical for widespread autoimmune treatment
• ▪The FDA should grant priority review to Kyverna's miv-cel for stiff person syndrome