Miv-cel Earns RMAT Designation for Progressive Multiple Sclerosis

According to a new announcement, the FDA has granted Regenerative Medicine Advanced Therapy (RMAT) designation to mivocabtagene autoleucel (miv-cel; Kyverna Therapeutics) for non-active secondary progressive multiple sclerosis (naSPMS). Miv-cel is an autologous CD19-targeting CAR T-cell therapy. The designation, granted in August 2026, was based on what the company described as compelling clinical data from an ongoing Stanford University investigator-initiated trial (IIT).

RMAT designation applies to regenerative medicine therapies, including cell therapies, showing preliminary clinical evidence of potential to address unmet medical needs for serious conditions. The designation provides Kyverna with increased FDA engagement and eligibility for priority and rolling review pathways as the company plans its regulatory strategy in naSPMS. It extends miv-cel's neuroimmunology franchise beyond the company's lead indication, stiff person syndrome (SPS), where a rolling Biologics License Application is already underway, and generalized myasthenia gravis (gMG), where a phase 3 registrational trial is enrolling.

"In progressive multiple sclerosis, miv-cel's potential to stabilize or improve disability status with a single dose could represent a transformative treatment advance given the steady progression patients face despite available therapies," Naji Gehchan, MD, chief medical and development officer of Kyverna Therapeutics, said in a statement. "We look forward to sharing our development strategy in progressive multiple sclerosis, leveraging discussions with the FDA through our RMAT designation, by early 2027."

RMAT designation basis and supportive phase 1 data in PMS

The RMAT designation drew on updated 12-month follow-up data from Stanford University's phase 1 investigator-initiated trial of miv-cel in progressive multiple sclerosis, presented at the Stanford Blood and Marrow Transplantation and Cellular Therapy Symposium in May 2026. Six patients with progressive MS have been treated, receiving either 33 million (n=3) or 100 million (n=3) CAR T cells using an alternative bendamustine lymphodepleting regimen, with 4 of 6 patients reaching 12 months of follow-up.

Miv-cel is manufactured autologously from each patient's own T cells through apheresis, ex vivo genetic engineering, and centralized manufacturing, followed by lymphodepleting chemotherapy before reinfusion. This manufacturing approach mirrors miv-cel's use in Kyverna's more advanced SPS and gMG programs, where the company has established commercial-scale supply capabilities.

CAR T expansion, immune reset biomarkers, and neuroimmunology pipeline

Reported findings showed robust CAR T-cell expansion in both blood and cerebrospinal fluid, along with reconstitution of naive B cells consistent with an immune reset mechanism. Kyverna has not disclosed disability status outcomes, adverse event rates, or CRS and ICANS grading from the Stanford IIT in its RMAT announcement. The company said it will report additional Stanford IIT data in the fourth quarter of 2026.

Miv-cel's RMAT designation in naSPMS follows earlier regulatory progress across Kyverna's neuroimmunology franchise. The company initiated a rolling BLA submission for miv-cel in SPS in 2026, supported by RMAT and orphan drug designations and positive phase 2 data, and continues enrolling patients in its FDA-aligned phase 3 gMG trial across 15 activated global sites. Kyverna has also secured a clinical and commercial supply agreement with ElevateBio to support anticipated scale-up.

Miv-cel joins a broader wave of CD19-directed CAR T-cell therapies advancing into neuroimmunologic and rheumatologic autoimmune disease beyond their original oncology indications, following early clinical signals of durable B-cell depletion and disease remission in small autoimmune cohorts. Kyverna's neuroimmunology franchise now spans three indications, SPS, gMG, and PMS, positioning miv-cel as one of the most clinically advanced autologous CAR T candidates in autoimmune neurology.

Non-active secondary progressive MS represents a difficult-to-treat MS subtype, as most approved disease-modifying therapies target relapsing, inflammatory disease activity rather than the gradual, non-relapsing progression characteristic of naSPMS. Kyverna expects to share its full PMS development strategy, including next steps toward a registrational program, by early 2027.

References

1. Kyverna Therapeutics Reports Pipeline Progress and Second Quarter 2026 Financial Results. News release. Kyverna Therapeutics. August 2026. https://finance.yahoo.com/healthcare/articles/kyverna-therapeutics-reports-pipeline-progress-200200302.html

2. Kyverna Therapeutics Announces Initiation of Rolling SPS BLA Submission and Reports First Quarter 2026 Financial Results. News release. Kyverna Therapeutics. May 12, 2026. https://ir.kyvernatx.com/news-releases/news-release-details/kyverna-therapeutics-announces-initiation-rolling-sps-bla

3. Kyverna Therapeutics, Inc. Form 10-Q. U.S. Securities and Exchange Commission. 2026. https://www.sec.gov/Archives/edgar/data/0001994702/000119312526344607/kytx-20260630.htm