How do you decide when to refer a patient with refractory multiple sclerosis for a CAR-T cell clinical trial?

CAR-T trials are numerous now, but all are very preliminary and mostly in phase I. If by "refractory" you mean continued disease activity (relapse, MRI +/- progression), then we would sooner consider aHSCT before referring to a CAR-T trial. If, however, the patient is no longer experiencing relapses...