Kyverna Presents Registrational Trial Primary Analysis for Miv-cel in Stiff Person Syndrome Demonstrating Statistically Significant, Durable Clinical Benefit Across All Endpoints in an Oral, Late-Breaker Session at AAN Annual Meeting

Single-dose of miv-cel achieved robust and durable improvements in mobility, reversed disability scores, and eliminated the need for chronic immunotherapies – outcomes not previously observed in SPS

Data underscore potential for miv-cel to become the first and only approved treatment for SPS, fundamentally changing the treatment paradigm for patients and caregivers

Company to host conference call on Wednesday, April 22, 2026, at 7:00 am ET

EMERYVILLE, Calif., April 21, 2026 (GLOBE NEWSWIRE) -- Kyverna Therapeutics, Inc. (Nasdaq: KYTX), a late-stage clinical biopharmaceutical company focused on developing cell therapies for patients with autoimmune diseases, today announced positive primary analysis results from its registrational trial, KYSA-8, of miv-cel (mivocabtagene autoleucel, KYV-101) in stiff person syndrome (SPS). The data will be presented today in a late-breaking oral presentation at the American Academy of Neurology (AAN) Annual Meeting in Chicago.

In KYSA-8, a single dose of miv-cel delivered rapid, statistically significant and clinically meaningful improvements across all primary and secondary endpoints at 16 weeks, with the majority of patients regaining function, and all patients discontinuing chronic immunotherapies – outcomes not previously observed in SPS. Further, miv-cel was well-tolerated.

“The results from our KYSA-8 registrational trial mark a defining moment for Kyverna, and more importantly, for patients living with stiff person syndrome,” said Warner Biddle, Chief Executive Officer of Kyverna Therapeutics. “We see compelling evidence that a one-time therapy can reset the immune system, reverse the course of disease, and free patients from lifelong treatment burden. With no approved therapies, we believe miv-cel could redefine the treatment paradigm for this debilitating, progressive disease. We are preparing our BLA submission for this initial indication, and the data strengthen our confidence in miv-cel’s therapeutic potential in myasthenia gravis, as well as other neurologic autoimmune diseases.”

KYSA-8 Clinical Trial Summary and Highlights from Primary AnalysisKYSA-8 is a single-arm registrational Phase 2 trial evaluating miv-cel in patients with SPS. The primary endpoints are the change from baseline in the Timed 25-Foot Walk (T25FW) at 16 weeks and the incidence and severity of adverse events (AEs). Secondary endpoints measuring disability, stiffness, hypersensitivity, and mobility include the Modified Rankin Scale (mRS), Distribution-of-stiffness Index (DSI), Heightened Sensitivity Scale (HSS), and Hauser Ambulation Index (HAI), respectively. Both DSI and HSS are SPS-specific clinical outcome measures designed to assess the extent of muscle stiffness and sensitivity to triggers of muscle spasms, respectively.

A total of 26 patients who had an inadequate response to off-label immunomodulatory treatment options received a single dose of 1×108 miv-cel CAR T cells. The data cut-off for the primary analysis was November 26, 2025, with a median follow-up of 6.5 months after miv-cel infusion (range, 4.4-12.2 months).

“The majority of patients with SPS suffer from a progressive condition that often results in loss of independence, reduced quality of life, and a high-risk of permanent disability,” said Amanda Piquet, M.D., FAAN, Director of Autoimmune Neurology at the University of Colorado Anschutz School of Medicine, Céline Dion Foundation Endowed Chair, and lead investigator of the KYSA-8 trial. “For decades, patients with SPS have had no approved therapies capable of altering the course of their disease. The ability of miv-cel to significantly decrease disability, stiffness, and hypersensitivity, and improve mobility – the key drivers of SPS morbidity – is unprecedented and highly promising for this underserved patient population.”

Efficacy highlights from the primary analysis following a single dose of miv-cel are as follows:

• The trial met its primary endpoint, demonstrating a statistically significant improvement in the T25FW at Week 16 (p=0.0003), with a median improvement of 46% from baseline, regardless of baseline patient- and disease-related characteristics:
  • 81% of patients achieved clinically meaningful improvement (≥20% reduction from baseline), with nearly 1/3 of all patients walking at the speed of healthy adults by Week 16.
  • Of the 12 patients requiring a walking aid at baseline, 67% no longer needed walking assistance at Week 16, reflecting meaningful functional independence.
  • All 26 patients remained free of chronic immunotherapies at Week 16 and through last follow-up.
• The trial met all secondary endpoints with significant (p