CAR-T Agent KYV-101 Show Durable Remission of Generalized Myasthenia Gravis in 1-Year Data

Newly announced One-year data from the phase 2/3 KYSA-6 trial showed that a single infusion of KYV-101 (miv-cel), an autologous CD19-targeting CAR T-cell therapy, produced durable, drug-free responses in patients with generalized myasthenia gravis (gMG). Kyverna Therapeutics also reported 1-year data from a separate registrational trial in stiff person syndrome (SPS), a second autoimmune neurologic disease for which the therapy is in development.¹

KYSA-6 results in generalized myasthenia gravis

For context, KYSA-6 is an open-label, single-arm, registrational phase 2/3 trial. Its phase 2 portion treated 7 patients with moderate to severe gMG who had failed prior immunosuppressant therapies, including FcRn and complement inhibitors, with a single infusion of miv-cel.¹ The results build on interim data presented at the 2025 AANEM Annual Meeting, when 6 patients had reached the 24-week mark.²

At 24 weeks, all 7 patients achieved clinically meaningful improvement on both the MG-ADL (mean reduction, 8.3 points) and QMG (mean reduction, 11.7 points) scales. Among the 5 patients who reached the 1-year mark, improvements were maintained, and 57% of patients had minimal symptom expression (MG-ADL score of 0 or 1) at last follow-up.

All 7 patients were free of standard immunotherapies at 24 weeks, and 86% (6 of 7) remained off immunosuppressants at last follow-up. No high-grade cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, or immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome occurred. Phase 3 enrollment is expected to complete in mid-2027.

“The durable clinical responses achieved in SPS and gMG, combined with a consistently favorable safety profile, set a new benchmark for autoimmune CAR T and reinforce miv-cel's potential best-in-class profile and ability to transform the treatment landscape across neurologic autoimmune diseases,” Warner Biddle, chief executive officer of Kyverna, said in a statement.¹

From RMAT designation to a registrational program

KYSA-6 followed the FDA's August 2024 decision to grant KYV-101 RMAT designation for progressive gMG, based on early data from patients treated under a named-patient compassionate use program in Germany.³ Miv-cel is a fully human, autologous CD19-targeting CAR T-cell therapy with CD28 co-stimulation, designed to achieve deep B-cell depletion and reset the immune system with a single dose; more than 100 patients have now been treated with the therapy across multiple autoimmune diseases.

One-year data in stiff person syndrome

KYSA-8, a single-arm, registrational phase 2 trial, enrolled 26 adults with SPS who had an inadequate response to at least 1 prior immunotherapy, treating them with a single miv-cel infusion. At 1 year, timed 25-foot walk performance had improved by a median of 46% at week 16 and 49% at month 12 (P <.0001), and 95% of patients who had a clinically meaningful response (a reduction of more than 20%) at the primary analysis sustained that benefit.

More than one-third of patients completed the walk test in under 5 seconds, comparable to healthy adults, and of 12 patients who required walking aids before treatment, 67% no longer needed assistance.

Ninety-two percent of patients remained free of chronic SPS immunotherapies, and the safety profile was consistent with the gMG cohort, with no high-grade cytokine release syndrome, neurotoxicity, or hemophagocytic lymphohistiocytosis-like events. “The results from KYSA-8 are compelling, particularly given the severe burden of SPS and the absence of approved therapies,” Amanda Piquet, MD, lead investigator on the trial, director of the Autoimmune Neurology Program and holder of the Celine Dion Foundation Endowed Chair in Autoimmune Neurology at the University of Colorado, said in a statement.

Kyverna said the 1-year SPS data strengthen a rolling biologics license application submission that remains on track for completion in the fourth quarter of 2026. Beyond gMG and SPS, KYV-101 is also being studied in refractory progressive multiple sclerosis under the FDA-cleared KYSA-7 study, part of a broader pipeline the company is advancing across autoimmune neurologic diseases.⁴

REFERENCES
1. Kyverna Therapeutics reports positive one-year data. News release. Kyverna Therapeutics, Inc. Published September 24, 2026. Accessed September 24, 2026. https://ir.kyvernatx.com/news-releases/news-release-details/kyverna-therapeutics-reports-positive-one-year-data
2. Kyverna Therapeutics announces positive interim phase 2 data from KYSA-6 study of KYV-101 in generalized myasthenia gravis at AANEM 2025. News release. Published October 29, 2025. Accessed September 24, 2026. https://www.globenewswire.com/news-release/2025/10/29/3176227/0/en/Kyverna-Therapeutics-Announces-Positive-Interim-Phase-2-Data-from-KYSA-6-Study-of-KYV-101-in-Generalized-Myasthenia-Gravis-at-AANEM-2025.html
3. Kyverna Therapeutics receives U.S. FDA RMAT designation for KYV-101 in the treatment of patients with progressive myasthenia gravis. News release. Published August 12, 2024. Accessed September 24, 2026. https://www.prnewswire.com/news-releases/kyverna-therapeutics-receives-us-fda-rmat-designation-for-kyv-101-in-the-treatment-of-patients-with-progressive-myasthenia-gravis-302220288.html
4. Kyverna's KYV-101 receives U.S. FDA clearance for treatment of patients with refractory, progressive multiple sclerosis in the KYSA-7 phase 2 trial. News release. Published January 3, 2024. Accessed September 24, 2026. https://www.prnewswire.com/news-releases/kyvernas-kyv-101-receives-us-fda-clearance-for-treatment-of-patients-with-refractory-progressive-multiple-sclerosis-in-the-kysa-7-phase-2-trial-302025646.html