Introduction B cells are implicated in MS pathophysiology. Ocrelizumab (OCR) is a humanised monoclonal antibody that selectively targets CD20+ B cells. OCR was evaluated in relapsing MS (RMS) in two identical, Phase III, randomised, double-blind, double-dummy, interferon beta-1a (IFNβ-1a)-controlled studies (OPERA I/NCT01247324 and OPERA II/NCT01412333).
Methods Eligible RMS patients were randomised 1:1 to receive OCR 600 mg every 24 weeks or IFNβ-1a 44 µg three-times weekly for 96 weeks. The primary endpoint was annualised relapse rate (ARR) by 96 weeks. Key secondary endpoints included: time to 12- and 24-week confirmed disability progression (CDP); total number of T1 gadolinium-enhancing and new/enlarging T2 lesions at weeks 24, 48 and 96; and safety.
Results Compared with IFNβ-1a, OCR reduced: ARR (OPERA I: 46%; OPERA II: 47%; both p<0.0001); 12- and 24-week CDP by 40% each (p=0.0006; p=0.0025, respectively) in pre-specified pooled analyses; T1 gadolinium-enhancing lesions (OPERA I: 94%; OPERA II: 95%; both p<0.0001); and new/enlarging T2 lesions (OPERA I: 77%; OPERA II: 83%; both p<0.0001). Except for infusion- and injection-related events, adverse events (AEs) and serious AEs were similar between groups.
Conclusions OCR demonstrated significantly superior efficacy vs IFNβ-1a and a favourable safety profile in RMS patients.