The Evolution of Anti-CD20 Treatment for Multiple Sclerosis: Optimization of Antibody Characteristics and Function

B-cell depletion with CD20-targeted agents is commonly used for treatment of multiple sclerosis (MS), other autoimmune diseases, and certain hematologic malignancies. Initial apparent success with rituximab in MS and neuromyelitis optica spurred development of the anti-CD20 monoclonal antibody (mAb) therapies ocrelizumab, ofatumumab, and ublituximab as well as the anti-CD19 mAb inebilizumab. While each are effective at targeting and depleting B cells, structural differences translate into different mechanisms of action affecting maintenance of B-cell depletion and safety and tolerability. Although the anti-CD20 mAbs differ in degree of human versus mouse sequences as well as target CD20 epitope, these properties do not appear to substantially affect activity or tolerability. In contrast, an antibody-dependent cell-mediated cytotoxicity (ADCC) versus a complement-dependent cytotoxicity mechanism of action as well as subcutaneous versus intravenous administration may provide improved tolerability. Glycoengineering of the mAbs ublituximab and inebilizumab enhances ADCC and can overcome the reduced responses to mAb-mediated B-cell depletion associated with certain genetic polymorphisms. Other strategies for therapeutic targeting of CD20, including brain shuttle antibodies (e.g., RO7121932), bispecific antibodies, chimeric antigen receptor T-cell therapies, and antibody-drug conjugates, are in active clinical development and may be future treatment approaches in MS and other B-cell-mediated autoimmune diseases.