Ocrelizumab for the treatment of multiple sclerosis.

INTRODUCTION: In the past decade, the role of B cells in the pathogenesis of multiple sclerosis (MS) is coming to the forefront. Depletion of B cells by anti-CD20 monoclonal antibodies (mAbs) has proved to decrease the activity of the relapsing-remitting MS (RRMS) and the progression of primary progressive MS (PPMS). Areas covered: In this review, the authors discuss the rationale of the depletion of B cells in RRMS and PPMS across recent studies on the role of B cells in the pathogenesis of MS; previous clinical trials with treatments targeting B cells; the mechanism of action of ocrelizumab - a second generation anti-CD20 mAb - and recent phase III clinical trials with ocrelizumab in RRMS and PPMS. Expert commentary: Ocrelizumab is the first anti-CD20 monoclonal antibody approved for RRMS and the first treatment approved for PPMS. The long-term effect and safety profile need to be evaluated in extension of clinical trials and in real-world studies.