Kyverna Therapeutics Reports Positive One-Year Data for Miv-cel in SPS and gMG

Kyverna Therapeutics, a biotech firm pioneering transformative therapies for neurologic autoimmune diseases, has announced positive one-year data from its registrational trial of miv-cel (mivocabtagene autoleucel, KYV-101) in patients with stiff person syndrome (SPS). The topline durability data reinforce the potential for a single-dose miv-cel to free patients from the life-long disease burden and chronic immunotherapies, further highlighting miv-cel’s differentiated construct.

Topline 12-month data from the KYSA-8 trial, which enrolled 26 adult patients with SPS who had an inadequate response to at least one immunotherapy treatment, demonstrated significant clinical benefits. The median improvement in the timed 25-Foot Walk (T25FW) was 46% at week 16 and 49% at month 12, with 95% of patients who achieved a clinically meaningful improvement (>20% reduction from baseline) sustaining their benefit. Sixty-seven percent of patients who required a walking aid prior to treatment no longer needed assistance. The data also showed that 92% of patients remained free of chronic immunotherapies for SPS, and miv-cel continued to be well-tolerated, with no high-grade cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS), and no cases of immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS).

Kyverna intends to include the one-year data in its rolling Biologics License Application (BLA) submission, which is on track to be completed in Q4 2026. The full data set will be presented at the joint ACTRIMS-ECTRIMS meeting, taking place October 21-23, 2026, in Toronto, Canada.

In a separate trial, the longer-term follow-up data from the Phase 2 portion of KYSA-6, which evaluated miv-cel in patients with generalized myasthenia gravis (gMG), demonstrated robust and durable effects sustained for up to 1.5 years. As of data cut-off in June 2026, follow-up now extends one year or longer in five patients, with one patient at 9 months and another at 6 months. All seven patients (100%) achieved clinically meaningful improvement in Myasthenia Gravis Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores at 24 weeks, with mean reductions of -8.3 and -11.7 points, respectively. Clinically meaningful improvements in MG-ADL, QMG, and Myasthenia Gravis Composite (MGC) scores maintained through one year or longer in all five patients who have reached this time point. Minimal symptom expression (MSE; defined as an MG-ADL score of 0 or 1) was maintained in 57% of patients as of the last follow-up. All seven patients (100%) remained free of immunotherapies for MG, including nonsteroidal immunosuppressive therapies, high-dose steroids (>10 mg), and FcRn and complement inhibitors at 24 weeks, with six of seven patients (86%) remaining off immunosuppressants as of the last follow-up. Miv-cel continued to be well-tolerated, with no high-grade CRS, no ICANS, and no cases of IEC-HS.

The Phase 3 portion of the KYSA-6 trial is ongoing, with enrollment expected to be completed in mid-2027. Kyverna will host a conference call on September 24, 2026, at 8 am ET to review the topline SPS and gMG longer-term follow-up data from KYSA-8 and KYSA-6, respectively. The conference call and live webcast details and presentation materials will be available on the "Events & Presentations" section of Kyverna's Investor Relations webpage at ir.kyvernatx.com. An archived replay will also be available.

Kyverna's miv-cel is a fully human, autologous, CD19-targeting CAR T-cell therapy with CD28 co-stimulation, uniquely designed for potency and tolerability with the potential to achieve deep B-cell depletion, reset the immune system, and deliver durable drug-free, disease-free remission in autoimmune diseases with a single dose. The company's commitment to delivering transformative therapies for patients with SPS and gMG is underscored by these unprecedented outcomes.