Kyverna Therapeutics, Inc. has unveiled groundbreaking data from its registrational trial of miv-cel, demonstrating statistically significant improvements in mobility and quality of life for patients with stiff person syndrome (SPS). The findings were shared during a late-breaking oral presentation at the American Academy of Neurology (AAN) Annual Meeting in Chicago, marking a pivotal moment for both the company and patients affected by this debilitating condition.
Positive Outcomes in KYSA-8 Trial
The Phase 2 trial, designated KYSA-8, evaluated the effects of a single dose of miv-cel (mivocabtagene autoleucel, KYV-101) among patients suffering from SPS. The primary endpoints included the change from baseline in the Timed 25-Foot Walk (T25FW) at 16 weeks, along with the incidence and severity of adverse events. Impressively, results revealed that most participants experienced substantial gains in mobility, with all patients able to discontinue chronic immunotherapies-an outcome that has not been reported in previous SPS studies. Learn more on Investopedia.
Specifically, the trial involved a cohort of 26 patients who had not responded adequately to off-label immunomodulatory treatments. After administration of a single dose of 1Ă—108 miv-cel CAR T cells, the data showed rapid and clinically meaningful changes across all primary and secondary endpoints at the 16-week mark. These secondary endpoints included various measures of disability, stiffness, hypersensitivity, and mobility, such as the Modified Rankin Scale (mRS) and the Hauser Ambulation Index (HAI).
Transformative Potential for Patients
Warner Biddle, Chief Executive Officer of Kyverna Therapeutics, expressed his enthusiasm for the trial's findings, stating, "The results from our KYSA-8 registrational trial mark a defining moment for Kyverna, and more importantly, for patients living with stiff person syndrome." He emphasized that the evidence indicates a one-time therapy could reset the immune system, reverse disease progression, and alleviate the burden of lifelong treatments for patients.
The data underscores the potential for miv-cel to become the first Approved therapy for SPS, offering hope to those grappling with this rare and often misunderstood condition. With no approved treatments currently available, the possibility of miv-cel changing the treatment landscape is significant. Biddle noted that the company is preparing its Biologics License Application (BLA) submission for this indication, which could pave the way for regulatory approval and wider access for patients.
Safety and Tolerability of Miv-cel
Importantly, the miv-cel therapy was well-tolerated among trial participants, a critical consideration in evaluating new treatments for autoimmune diseases. The incidence and severity of adverse events were closely monitored, providing reassurance about the safety profile of this innovative therapy.
As Kyverna moves forward with its plans to submit for regulatory approval, the promising results from the KYSA-8 trial could also extend beyond SPS. Biddle indicated an interest in exploring miv-cel's therapeutic potential in other neurologic autoimmune diseases such as myasthenia gravis. This broader application could enhance the drug's impact and help numerous patients facing similar challenges with their health.
Upcoming Conference Call and Future Prospects
To discuss the trial results and next steps, Kyverna will host a conference call on Wednesday, April 22, 2026, at 7:00 am ET. This call will provide further insights into the implications of the KYSA-8 findings and the company's strategic direction as it seeks to advance miv-cel through the regulatory process.
As awareness grows about stiff person syndrome and its impact on patients, the results from the KYSA-8 trial present a hopeful narrative. With miv-cel potentially on the cusp of approval, Kyverna Therapeutics may not only reshape the treatment landscape for SPS but also inspire a renewed focus on innovative therapies within the realm of autoimmune diseases.
Originally reported by Globe Newswire. View original.