Ofatumumab is a novel Immunoglobulin 1ĸ ( IgG1ĸ) lytic monoclonal antibody (mAb) that specifically binds to the human Cluster of Differentiation 20 (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.