Kyverna data sets stage for first FDA-approved CAR-T for autoimmune disease

Kyverna Therapeutics announced positive topline data from its registrational phase 2 trial of mivocabtagene autoleucel (miv-cel), a fully human, autologous CD19-targeting CAR-T cell therapy with CD28 co-stimulation, in stiff person syndrome (SPS).

According to Kyverna, the landmark results from the KYSA-8 trial could pave the way for miv-cel to become the first FDA-approved CAR-T cell therapy for autoimmune disease. Based on these data, Kyverna plans to submit a BLA to the FDA for SPS in the first half of 2026.

KYSA-8 is a single-arm registrational phase 2 trial in which patients with SPS, who had an inadequate response with non-approved treatment options, received a single dose of miv-cel. A total of 26 patients were dosed and followed through the primary analysis time point (week 16) with additional follow-up.

“With a single dose, miv-cel achieved highly statistically significant and sustained improvements in overall disability, mobility, and stiffness, while enabling all patients to remain free of immunotherapies. In addition, miv-cel demonstrated a well-tolerated and manageable safety profile. We believe these unprecedented results, which support our BLA submission, will have a profound impact on patients,” said Naji Gehchan, Kyverna chief medical and development officer. 

Specifically, miv-cel demonstrated a robust and sustained improvement in mobility with a highly statistically significant improvement in timed 25-foot walk (T25FW) — the study’s primary endpoint. 81% of patients exceeded a 20% improvement in T25FW, a threshold considered clinically meaningful. In additional, highly statistically significant benefit was also achieved across all secondary endpoints, including the Modified Rankin Scale, Distribution-of-stiffness Index, Hauser Ambulation Index (HAI), and Heightened Sensitivity Scale. Of the 12 patients who required a walking aid-device prior to treatment, 67% no longer needed assistance to walk at week 16.

SPS is a rare, progressive neurologic autoimmune disease characterized by muscle stiffness and painful muscle spasms, impacting mobility and gait. Stiffness can lead to progressive disability causing up to 80% of patients to lose mobility.