CAR T shows staying power in neurologic autoimmune diseases

New topline data from Kyverna Therapeutics' registrational studies suggest that its investigational CD19-directed CAR T-cell therapy, mivocabtagene autoleucel (miv-cel), may provide sustained clinical benefit in both stiff person syndrome (SPS) and generalized myasthenia gravis (gMG).

CAR T-cell therapies have transformed some blood cancers, but their role in autoimmune disease remains investigational. Durable benefits after a single infusion could signal a shift away from chronic immunosuppressive treatment toward longer-lasting disease control in select autoimmune disorders.

In the 26-patient KYSA-8 SPS trial, improvements in mobility observed at the primary analysis were maintained through 12 months. Median timed 25-foot walk performance improved by 49% from baseline at 1 year, and 95% of patients who achieved a clinically meaningful response initially maintained that benefit. Among patients who required a walking aid before treatment, 67% no longer needed assistance. Additionally, 92% remained free of chronic SPS immunotherapies.

In the phase 2 portion of the KYSA-6 gMG trial (N=7), all patients achieved clinically meaningful improvements in Myasthenia Gravis Activities of Daily Living (MG-ADL)andQuantitative Myasthenia Gravis (QMG) scores at 24 weeks. Among those followed for at least 1 year, improvements in these disease measures were sustained, while 86% remained off immunosuppressive therapies at last follow-up.

No high-grade cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), or immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome were reported in either study.

Kyverna said its rolling biologics license application for SPS remains on track for completion in Q4 2026. Meanwhile, the phase 3 portion of the gMG program is ongoing, with enrollment expected to be completed in mid-2027. If successful, miv-cel could become the first approved CAR T-cell therapy for an autoimmune disease.

Source: Kyverna Therapeutics. (2026 Sep 24). Kyverna Therapeutics Reports Positive One-Year Data Demonstrating Durable Clinical Responses and Favorable Safety Profile for Miv-cel in Stiff Person Syndrome and Generalized Myasthenia Gravis