Kyverna Therapeutics said its patient‑specific CAR‑T therapy produced clinically meaningful improvements in mobility and stiffness in a registrational trial for stiff person syndrome, meeting the study’s primary endpoint and enabling plans to submit to the FDA in the first half of 2026. The company released topline results and stated the dataset will form the basis of its marketing application. The outcome marks one of the first successful late‑stage CAR‑T studies in an autoimmune neurological disease rather than oncology. Kyverna emphasized functional endpoints and safety data in its announcement and plans follow‑on engagements with regulators to agree on submission timing and label expectations.