Ofatumumab’s mechanism of action

Ofatumumab (Ofatumumab)specifically binds to the large and small extracellular loops of the CD20 molecule, which is expressed on normal B lymphocytes (pre-B lymphocytes to mature B lymphocytes) and B-cell CLL. CD20 molecules are not shed from the cell surface, nor are they internalized upon antibody binding. The Fab domain of ofatumumab binds to the CD20 molecule, and the Fc domain mediates immune effector function, leading to B cell lysis in vitro. The mechanism by which ofatumumab exerts its therapeutic effect in patients with multiple sclerosis is unclear, but is hypothesized to be due to its ability to bindCD20. Data suggest that possible mechanisms of cell lysis include complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity.