*2.4.4 Ofatumumab*

Ofatumumab is a fully human anti-CD20 monoclonal antibody [129]. It induces antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity in CD20-expressing B lymphocytes. Ofatumumab is highly potent in lysing B cells, as this appears to stem from its binding site on the short extracellular loop of the target CD20 protein and its slow release from the target molecule. Ofatumumab has been successfully applied in a patient with SLE and hypocomplementemia in combination with fresh frozen plasma [130]. Ofatumumab, has been used as B cell depleting therapy in SLE patients who developed severe infusion reactions to rituximab [131]. The agent was well tolerated and may be a safe and effective alternative to rituximab for B cell depletion treatment in SLE.
