Kyverna to seek FDA engagement after positive autoimmune CAR-T data in stiff person syndrome
Kyverna Therapeutics reported encouraging early clinical results using its CD19-directed CAR-T cell therapy KYV-101 in patients with severe stiff person syndrome (SPS), a rare autoimmune neurological disorder marked by muscle rigidity and spasms.
Data presented showed meaningful reductions in stiffness scores and spasm frequency and, in some cases, improved mobility and function in SPS patients who had previously failed or relapsed on standard immunotherapies such as IVIG, benzodiazepines, and rituximab.
The safety profile in the SPS cohort was generally manageable, with cytokine release syndrome (CRS) and neurotoxicity mostly low grade and reversible with standard interventions, consistent with what is seen in oncology CAR-T use but without unexpected new safety signals.
These results add to Kyverna’s broader autoimmune CAR-T program, where KYV-101 is also being studied in other B‑cell–driven autoimmune conditions such as lupus nephritis and myasthenia gravis, supporting a platform approach for autoimmunity rather than cancer.
On the back of the SPS data, Kyverna has stated its intention to engage with the U.S. Food and Drug Administration to define a regulatory path forward for KYV-101 in autoimmune indications, including discussions on trial design, potential expedited pathways, and requirements for a future pivotal study.
Because SPS is ultra‑rare and has high unmet medical need, Kyverna is expected to explore options such as Breakthrough Therapy or RMAT (Regenerative Medicine Advanced Therapy) designation if subsequent data continue to show strong efficacy and acceptable safety.
The SPS results further validate the concept that deeply depleting autoreactive B cells with CD19 CAR-T can induce durable immunologic reset in autoimmune disease, strengthening the competitive positioning of Kyverna among a growing field of autoimmune cell-therapy developers.