Mayo Clinic trial of CAR-T therapy restores mobility in stiff person syndrome patients

A single dose for a rare disease

Researchers at the Mayo Clinic in Rochester tested CAR-T cell therapy in a clinical study published on 9 November 2026 in JAMA Neurology. The study enrolled 26 adults with stiff person syndrome, a rare autoimmune disorder that affects the central nervous system and causes progressive muscle stiffness and painful spasms. All of them had not responded well enough to earlier immunological treatments. Each received a single dose, which involves taking T cells from the patient's blood, modifying them in a laboratory and returning them to the body so they can recognise and destroy the cells driving the disease. The treatment was designed to restore immune function and reduce the most disabling symptoms. CAR-T is already used against certain blood cancers, and Sean Pittock, head of neurology at the Mayo Clinic, said its potential is now emerging in autoimmune neurological diseases.

Patients regaining everyday function

The improvements were large in some patients. People who had needed help with walking and basic daily tasks regained the ability to move and carry out routine activities, and some went back to work and their hobbies. Jonathan Walden, a trial participant who had relied on his family for help with walking and routine tasks, said he has resumed working and his favourite activities. He almost talked himself out of joining the trial, but decided that the risk was worth taking. He added:

“I have not had one episode since receiving treatment.”

Another participant, a woman diagnosed in 2021, had severe leg cramps and trouble walking. By 2024 standard treatments no longer controlled her symptoms, and sudden noises had triggered muscle rigidity and falls. In the months after CAR-T she began to improve and was able to walk on a treadmill again.

Researchers urge caution

Anastasia Zekeridou, a neurologist and researcher at the Mayo Clinic in Rochester, described the degree of improvement in some patients as the most striking finding. Current treatments can ease symptoms, she said, but patients very rarely return to their earlier level of function. She called the preliminary results very encouraging and said the key question is whether the gains last over time. The researchers consider further studies with more patients necessary, and the study could lead to larger trials in people with stiff person syndrome.

Background and open questions

Stiff person syndrome, first described by the Mayo Clinic in 1956, has no definitive cure. Available medicines can ease symptoms and control the immune response, but they do not always stop the disease from progressing. Symptoms can be triggered by unexpected noises, touch or strong emotions. Celine Dion disclosed her diagnosis in December 2022, saying the illness also affected her voice and forced her to cancel some appearances and concerts.

The sample is small and the follow-up period is not reported as long enough to show whether the benefits will hold. Researchers have not yet determined how long the improvements last.