Onset of clinical and MRI efficacy of ocrelizumab in relapsing multiple sclerosis

Objective: To assess the onset of ocrelizumab efficacy on brain magnetic resonance imaging (MRI) measures of disease activity in the Phase II study in relapsing-remitting multiple sclerosis (RRMS), and relapse rate in the pooled Phase III studies in relapsing multiple sclerosis (RMS).

Methods: Brain MRI activity was determined in the Phase II trial at monthly intervals in patients with RRMS receiving placebo, ocrelizumab (600 mg), or intramuscular interferon (IFN) β-1a (30 μg). Annualized relapse rate (ARR; over various epochs) and time to first relapse were analyzed in the pooled population of the Phase III OPERA I and OPERA II trials in patients with RMS receiving ocrelizumab (600 mg) or subcutaneous IFN β-1a (44 μg).

Results: In patients with RRMS, ocrelizumab reduced the number of new T1 gadolinium-enhancing lesions by Week 4 vs placebo (p=0.042) and by Week 8 vs intramuscular IFN β-1a (p<0.001). Ocrelizumab also reduced the number of new or enlarging T2 lesions appearing ...