Science & technology

CAR-T Trial Finds Mobility Gains for Stiff Person Syndrome

Is CAR-T a turning point for stiff person syndrome or is its ability to reset the immune system still unclear?

5 hours ago·Updated 54 minutes ago

CAR-T Trial Finds Mobility Gains for Stiff Person Syndrome

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Above: Celine Dion is seen in Paris, France, on Oct. 14, 2026. Image credit: Marc Piasecki/Getty Images

The Facts

A one-time CAR-T cell therapy produced marked improvements in patients with stiff person syndrome, according to trial results published Monday in JAMA Neurology. The rare autoimmune condition also affects singer Celine Dion.
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The Guardian
There are no FDA-approved treatments for stiff person syndrome, and Kyverna Therapeutics says it has begun a rolling Biologics License Application submission of mivocabtagene autoleucel (miv-cel), which would be the first CAR-T cell therapy approved for an autoimmune disease.
Kyverna Therapeutics, Inc.
Kyverna Therapeutics, Inc.
In the single-arm KYSA-8 trial, 26 adults received one infusion, and the median improvement in the timed 25-foot walk at 16 weeks was 45.6%. Of the 12 patients who used walking aids at the start, eight no longer needed them to complete the timed walks.
JAMA Network
Kyverna Therapeutics, Inc.
Cytokine release syndrome occurred in 24 of the 26 treated patients, though all cases were low grade, and neutropenia was the most common severe treatment-related event. Every patient remained off immunomodulatory therapy at last follow-up.
JAMA Network
Kyverna Therapeutics, Inc.
Participant Jonathan Walden, who had needed family help to walk, said he has returned to work, hunting and fishing and has "not had one episode since receiving treatment." Another patient, Shari St Germain, walked on a treadmill again.
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The Standard
IFLScience
Dion announced her diagnosis in December 2022, saying the condition had harmed her voice. She has said symptoms appeared about 17 years before that diagnosis, and on Sept. 12 she performed in France in her first full concert in six years.
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The Spin

Techno-optimist narrative

Finally, there's a real shot at reversing stiff person syndrome instead of just dulling the symptoms. Getting patients off walkers and back to work, hunting and fishing is the kind of result decades of off-label immunotherapy never delivered. A single dose that frees people from chronic immunotherapy is a genuine turning point, offering hope to patients like Celine Dion.

Kyverna Therapeutics, Inc. on X

Mayo Clinic

The Guardian

Techno-skeptic narrative

Promising results are not proof of a lasting immune reset. Researchers still need to establish whether CAR-T fundamentally changes the immune response and how long the benefits persist. Other autoimmune CAR-T programs have raised serious safety concerns, including three patient deaths in Novartis trials. Even if miv-cel's results hold up, it must still clear FDA review before becoming an approved treatment for stiff person syndrome.