Kyverna Therapeutics Inc. (Nasdaq: KYTX) announced positive results from a registrational trial for its cell therapy miv-cel in patients with stiff person syndrome, with data showing the treatment reversed disability and improved mobility, sending its stock up more than 23%.
“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,” Warner Biddle, Chief Executive Officer of Kyverna Therapeutics, said in a statement. “With no approved therapies, we believe miv-cel could redefine the treatment paradigm for this debilitating, progressive disease.”
The primary analysis from the KYSA-8 Phase 2 trial showed that a single dose of miv-cel led to statistically significant and clinically meaningful improvements across all endpoints at 16 weeks. Notably, 85% of the 26 patients experienced a meaningful improvement in the Timed 25-Foot Walk, a key measure of mobility. The therapy also demonstrated a well-tolerated safety profile, with no instances of high-grade cytokine release syndrome (CRS) or neurotoxicity.
The results position miv-cel to potentially become the first and only approved treatment for stiff person syndrome, a rare and progressive neurologic disease that affects an estimated 6,000 people in the U.S. Kyverna is now preparing its Biologics License Application for submission to the Food and Drug Administration.
A Potential Immune Reset
Miv-cel is an autologous, CD19-targeting CAR T-cell therapy. The treatment involves engineering a patient's own T-cells to target and deplete B-cells, which are understood to be the source of pathogenic autoantibodies in many autoimmune diseases. The goal is to achieve a deep immune system reset with a single administration, offering the potential for durable, drug-free remission.
In the KYSA-8 trial, this mechanism showed strong results. Beyond the mobility improvements, 77% of patients saw their disability scores improve on the Modified Rankin Scale, and all patients were able to discontinue the chronic off-label immunotherapies they previously relied on.
“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,” said Amanda Piquet, lead investigator of the trial and Director of Autoimmune Neurology at the University of Colorado.
Path to Market
While the clinical data is strong, the market has previously discounted Kyverna due to the small sample sizes of its trials and perceived execution risk, according to analyst reports. The company holds a cash balance of $279 million, providing an estimated runway of 19-20 months against an annual burn of roughly $170 million. A recently filed $300 million mixed securities shelf provides further liquidity but also signals potential shareholder dilution ahead as the company prepares for commercialization.
The bull case rests on miv-cel’s potential as a transformative, one-time therapy not just for SPS but as a platform for other B-cell-driven autoimmune diseases, including generalized myasthenia gravis (gMG). If the upcoming Phase 3 trials validate these early findings, the current enterprise value of approximately $350 million could represent an early entry point.
The positive data provides a significant de-risking event for Kyverna as it moves toward its BLA submission. Investors will now be closely watching for the formal submission to the FDA and any subsequent regulatory feedback, which represents the next major catalyst for the company.
This article is for informational purposes only and does not constitute investment advice.
