KYTX · Kyverna Therapeutics, Inc.

Kyverna Therapeutics disclosed positive topline data from two key neuroimmunology programs via press releases on April 20 and 21, 2026, under Item 7.01 Regulation FD. The KYSA-8 registrational trial in stiff person syndrome (SPS), a debilitating condition with no FDA-approved therapies, met its primary endpoint of significant T25FW improvement with a 46% median reduction at Week 16. Notably, 81% of patients achieved ≥20% improvement, 31% showed 4-fold improvement, and Week 16 scores approached healthy adult levels. All patients were 100% free of immunotherapies from Week 16 onward, supported by robust miv-cel expansion, complete B-cell depletion, and 56% median reduction in GAD65-IgG autoantibodies. This reinforces miv-cel's potential as first-in-class CAR T for autoimmune diseases, with BLA preparations underway for SPS, a valuable market opportunity. In parallel, longer-term data from the Phase 2 portion of KYSA-6 in generalized myasthenia gravis (gMG) showed deepening responses out to 52 weeks, with 100% of patients immunotherapy-free up to 24 weeks across MG-ADL, QMG, and MGC scales, and majority achieving minimal symptom expression. These results bolster confidence in the ongoing Phase 3 gMG trial. Miv-cel, a fully human CD19 CAR T with CD28 costimulation, demonstrated no high-grade CRS or ICANS across over 100 patients dosed. The company is hosting a conference call today with slides in Exhibit 99.1 to detail findings, positioning Kyverna to potentially deliver the first approved autoimmune CAR T and transform treatment paradigms with durable, drug-free remission from a single dose.