Disability Worsening Independent of Relapses in Multiple Sclerosis

Multiple sclerosis (MS) relapses can result in disability if patients do not return to baseline. Worsening disability is also understood to occur even when a relapse is not identified. Investigators pooled data from the two ocrelizumab phase III studies in 1656 patients with relapsing-remitting MS to examine relapse associated worsening (RAW) versus progression independent of relapse activity (PIRA). Confirmed worsening — as measured by the Expanded Disability Status Scale, 25-foot timed walk, or 9-hole peg test — occurred in 21% on ocrelizumab and 30% on interferon. PIRA occurred in 78% on interferon and 88% on ocrelizumab.