Ofatumumab is a novel IgG1? lytic monoclonal antibody (mAb) that specifically binds to the human CD20 antigen of which expression is restricted to B lymphocytes from the pre-B cell stage to the plasmacytoid immunoblast stage only. A recent trial with an anti-CD20 mAb (rituximab) demonstrated that targeting B-cells reduces the number of gadolinium-enhancing (GdE) T1 lesions and the relapse rate in relapsing-remitting multiple sclerosis (RRMS). Ofatumumab has been shown to be both well tolerated and efficacious in several indications, including a small, placebo-controlled trial in RRMS using an intravenous (IV) formulation.

This double-blind, placebo-controlled, parallel-group study will investigate the safety and efficacy of a subcutaneous formulation of ofatumumab in the treatment of subjects with RRMS. The primary objective of the study is to investigate the efficacy as assessed by magnetic resonance imaging. Other objectives will include evaluation of tolerability/safety, dose-response relationship, pharmacokinetics, pharmacodynamics, exposure-response, as well as other clinical endpoints.