Has the Time Come to Revisit Our Standard Measures of Disability Progression in Multiple Sclerosis?

For decades, progression of disability in multiple sclerosis (MS) was assessed by a confirmed increase in Expanded Disability Status Scale (EDSS) score. It is the typical primary endpoint in phase 3 clinical trials in progressive MS, where the lack of effect of most immunotherapies on confirmed disability progression is usually interpreted as the lack of protection from cumulative damage to the CNS.