A U.S. clinical trial of CAR-T cell therapy for stiff person syndrome, a rare autoimmune neurologic condition also diagnosed in singer Celine Dion, found early functional gains in some participants, researchers at Mayo Clinic said, with results published Monday in JAMA Neurology^1,2.

Stiff person syndrome can cause progressive muscle stiffness, painful spasms and difficulty walking; there is no established cure^1,2. The Manchester Evening News said the condition is thought to affect about 8,000 people worldwide, more often women, with symptoms typically starting between ages 20 and 60². Dion publicly described her diagnosis in December 2022^1,2.

CAR-T therapy, already used against some cancers, involves extracting a patient's T cells, engineering them and returning them as a one-time treatment intended to target disease-driving immune cells^1,2. The Manchester Evening News said the product is already approved on the NHS for certain cancers².

Both outlets described two trial patients. Jonathan Walden had needed family help with walking and daily tasks; after treatment he said he had returned to work and had not had another episode². Shari St Germain, diagnosed in 2021, had severe leg cramps, startle-triggered rigidity and falls; she later walked on a treadmill for seven minutes, according to comments reported by the Manchester Evening News².

Dr. Anastasia Zekeridou, a Mayo Clinic neurologist in Rochester, Minnesota, said existing drugs rarely restore prior function and that the main unanswered question is whether the gains last^1,2. Dr. Sean Pittock, chair of Mayo's neurology department, said the work may extend to other immune-mediated neurologic diseases, while adding that much remains unknown^1,2.

Yasmin Sheikh of the U.K. blood-cancer charity Anthony Nolan, which was not part of the trial, said the study adds evidence that CAR-T may apply beyond blood cancers and that specialist workforce and infrastructure would be needed if such treatments move into practice².

The reports describe an early, nonrandomized study. Neither article stated how many people were treated, how long they were followed, or how often serious CAR-T side effects occurred^1,2. Larger trials and longer follow-up have not been completed^1,2.

Not medical advice.