Abstract
BACKGROUND AND PURPOSE: Requiring a walking aid is a fundamental milestone in multiple sclerosis (MS), represented by an Expanded Disability Status Scale (EDSS) score ≥6.0. In the present study, we assess the effect of ocrelizumab (OCR) on time to EDSS score ≥6.0 in relapsing MS. METHODS: Time to EDSS score ≥6.0 confirmed for ≥24 and ≥48 weeks was assessed over the course of 6.5 years (336 weeks) in the double-blind period (DBP) and open-label extension (OLE) period of the OPERA I (NCT01247324) and OPERA II (NCT01412333) studies. RESULTS: Time to reach EDSS score ≥6.0 was significantly delayed in those initially randomized to OCR versus interferon. Over 6.5 years, the risk of requiring a walking aid confirmed for ≥24 weeks was 34% lower among those who initiated OCR earlier versus delayed treatment (average hazard ratio [HR] DBP + OLE 0.66, 95% confidence interval [CI] 0.45-0.95; p = 0.024); the risk of requiring a walking aid confirmed for ≥48 weeks was 46% lower (average HR DBP+OLE 0.54, 95% CI 0.35-0.83; p = 0.004). CONCLUSION: The reduced risk of requiring a walking aid in earlier initiators of OCR demonstrates the long-term implications of earlier highly effective treatment.