Kyverna Therapeutics, Inc. (Nasdaq: KYTX) announced positive one-year topline data from its registrational trial, KYSA-8, for its candidate miv-cel in patients with stiff person syndrome (SPS). The company also disclosed positive longer-term follow-up data from the Phase 2 portion of its registrational trial, KYSA-6, for miv-cel in patients with generalized myasthenia gravis (gMG). The data was released in a press release on September 24, 2026, and will be shared at upcoming medical meetings.
Regarding the SPS trial, 26 adult patients with an inadequate response to immunotherapy received a single dose of miv-cel. As of a July 2026 database lock, 12-month follow-up data showed significant improvements in mobility. The median improvement in the timed 25-Foot Walk (T25FW) was 46% at week 16 and 49% at month 12 (p < 0.0001). Of the 12 patients requiring a walking aid prior to treatment, 67% continued to not require assistance. Additionally, 92% of patients remained free of chronic immunotherapies for SPS. The therapy was well-tolerated with no high-grade cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS).
In the gMG trial, follow-up data extends to 1.5 years for five patients. As of a June 2026 data cut-off (n=7), all patients achieved clinically meaningful improvement in MG-ADL and QMG scores at 24 weeks. Mean reductions were -8.3 points for MG-ADL and -11.7 points for QMG. Clinically meaningful improvements were maintained through one year or longer in all five patients who reached that time point. The majority of patients maintained minimal symptom expression, and 86% of patients remained off immunosuppressants as of the last follow-up. The safety profile remained consistent, with no high-grade CRS, ICANS, or immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS).
Kyverna intends to include the one-year SPS data in its rolling Biologics License Application (BLA) submission, which is on track for completion in the fourth quarter of 2026. The company will host a conference call on September 24, 2026, at 8:00 a.m. Eastern Time to review the results. The Phase 3 portion of the KYSA-6 trial is ongoing, with enrollment expected to be completed in mid-2027.
