NEW YORK, June 3, 2026, 12:13 EDT
Kyverna Therapeutics shares were little changed on Wednesday after the company released updated early-stage rheumatoid arthritis data for miv-cel, its lead autoimmune cell therapy, leaving investors to weigh a broader pipeline story against the usual limits of a tiny trial.
The timing matters because Kyverna is trying to show that miv-cel can be more than a single-disease bet. CAR T, or chimeric antigen receptor T-cell therapy, re-engineers immune cells to attack a target; miv-cel is an autologous therapy, meaning it is made from a patient’s own cells, and targets CD19, a marker found on B cells involved in several autoimmune diseases.
Kyverna shares were recently down less than 0.1% at $7.90, giving the company a market value of about $477 million. The stock lagged the broader biotech tape: the SPDR S&P Biotech ETF rose about 1.0%, while the iShares Nasdaq Biotechnology ETF gained about 1.2%.
Kyverna said updated data from the Phase 1 portion of COMPARE, an investigator-led Phase 1/2 study in active ACPA-positive, treatment-refractory rheumatoid arthritis, showed that four of six patients, or 66.6%, met ACR70 by Week 36. ACR70 means a patient has at least a 70% improvement by American College of Rheumatology criteria. The company said there were no high-grade cases of cytokine release syndrome, an excessive immune reaction, and no ICANS, a neurological side effect seen with some cell therapies.
Naji Gehchan, Kyverna’s chief medical and development officer, said the update added to a “growing body of evidence” across autoimmune indications. David Simon, head of the clinical trial unit at Charité’s rheumatology and clinical immunology department and principal investigator of COMPARE, said miv-cel showed a “depth of B-cell depletion” in difficult-to-treat rheumatoid arthritis. GlobeNewswire
The Phase 2 portion of COMPARE has been started and is fully enrolled, Kyverna said. That part of the trial compares miv-cel with rituximab, an older anti-CD20 antibody used to deplete B cells, in the same hard-to-treat rheumatoid arthritis population.
The bigger near-term catalyst remains stiff person syndrome, a rare neurological autoimmune disorder. In May, Kyverna said it had begun a rolling biologics license application, or BLA, for miv-cel in that disease after a pre-BLA meeting with the U.S. Food and Drug Administration. A BLA is the FDA filing used to seek approval for a biologic medicine. Kyverna said it expected to complete the submission in the fourth quarter of 2026 and reported $236.4 million in cash, cash equivalents and marketable securities as of March 31, with runway into 2028.
Chief Executive Warner Biddle called the FDA alignment a “significant milestone” in an SEC-filed exhibit last month, saying the company was preparing for a 2027 launch if the drug is cleared. That is still a big if, and it is where the stock will likely keep trading: less on one small rheumatoid arthritis update, more on regulatory execution and launch risk. SEC
The field is getting crowded. Cabaletta Bio, another autoimmune CAR-T developer, also released EULAR 2026 data on Wednesday for rese-cel across autoimmune diseases including myositis, systemic sclerosis and lupus; its shares were down about 4.3% in midday trading.
But the risk case is plain. Kyverna’s rheumatoid arthritis data come from only six Phase 1 patients, and small early trials can look cleaner than larger controlled studies. If the Phase 2 comparison with rituximab disappoints, if safety changes with broader use, or if regulators ask for more data on miv-cel in stiff person syndrome, the stock could give back any confidence built around the platform.
For now, the share reaction was muted. Kyverna management is scheduled to present later Wednesday at the Jefferies Global Healthcare Conference, giving investors another same-day chance to press the company on miv-cel’s data, the BLA timetable and how much of the autoimmune CAR-T market it can realistically claim.
