Walking gains last a year in small stiff person syndrome trial

Walking improvements persisted for a year in a small trial of an experimental cell therapy for stiff person syndrome, a rare autoimmune disease that causes muscle stiffness and painful spasms.

All 26 adults completed the one-year follow-up after a single dose of miv-cel. The median reduction in the time needed to walk 25 feet (7.6 metres) was 49% compared with before treatment. Eight of the 12 participants who initially needed a walking aid completed the test without one, though that does not establish whether they stopped using aids in daily life.

At one year, 24 participants were also no longer receiving ongoing treatments that suppress or modify the immune system to manage the disease.

The Kyverna-sponsored study was led by the University of Colorado Anschutz, with findings presented on October 21 in Toronto. Miv-cel is a CAR T-cell therapy: a patient’s own immune cells are modified to target B cells involved in the autoimmune attack. The aim is to address the disease process rather than only ease symptoms.

The findings are promising, but the trial had no comparison group, so it cannot establish how much of the improvement the therapy caused. Three participants had serious treatment-related side effects, all of which resolved, according to Kyverna. Longer-term safety and durability remain uncertain, and miv-cel is not yet approved.