Kyverna Reports Strong Early Responses for CAR T Therapy KYV-101 in Myasthenia Gravis Trial

EMERYVILLE, CA — October 29, 2025 — Kyverna Therapeutics today reported positive early clinical data demonstrating that its investigational CAR T-cell therapy, KYV-101, induced responses in all patients treated for refractory generalized myasthenia gravis (gMG). The findings come from the open-label Phase 2 portion of a Phase 2/3 study. All six patients in the cohort, whose disease had progressed despite treatment with other advanced therapies (such as complement and FcRn inhibitors), responded to the single-infusion treatment.

Robust Clinical Improvement

The key findings, which contributed to an 8% rise in the company’s premarket stock price before settling slightly lower at the open, showed substantial symptom reduction:

• 100% Response Rate: All six treated patients achieved a clinical response.
• Symptom Reduction: Patients saw an average reduction of 8.0 points in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score after 24 weeks.
• Comparative Efficacy: An investigator in the study, Sri Muppidi, emphasized that the average change in the MG-ADL score was “higher than some of the Phase 3 studies that have been published today” for patients with moderate-to-severe gMG.

KYV-101 is an autologous CD19-targeted CAR T therapy that is being adapted from oncology to treat autoimmune disorders.

Path to Phase 3 and Simplified Regimen

Based on the data, Kyverna plans to advance immediately into the Phase 3 portion of the trial, aiming to enroll approximately 60 patients. The Phase 3 study will compare KYV-101 against the current standard of care (immunosuppressants and steroids) and will specifically track how many patients can discontinue background immunosuppressants.

According to Warner Biddle, CEO of Kyverna, the company’s approach involves a low-dose pretreatment chemotherapy regimen that can be administered in an outpatient setting over a few days. He noted that this simplified approach, coupled with the absence of severe immune response side effects (such as high-grade ICANS), makes for a “relatively easy treatment journey” compared to the typical CAR T experience.

While generally well-tolerated, three cases of severe neutropenia (low white blood cell count) were observed, with one advancing to Grade 4. The Grade 3 events resolved within 10 days, and the Grade 4 event lessened to mild within 90 days. Neutropenia is a known and manageable side effect of CAR T-cell therapy.

Kyverna expects to enroll its first Phase 3 patients by the end of the year.