Ofatumumab is a subcutaneously administered, fully human anti-CD20 monoclonal antibody, approved for the treatment of relapsing multiple sclerosis. It is considered a highly effective therapy, and at the same time has a good safety and tolerability profile. This review presents up-to-date information regarding the general safety profile of ofatumumab, including the incidence of serious infections, injection-related reactions, malignancies, and effects on laboratory parameters, such as immunoglobulins M and G, and lymphocyte and neutrophil counts. Currently available data show that the most common adverse effects of ofatumumab include upper respiratory tract infections (mild to moderate), injection-related reactions (mild to moderate, and very rare beyond the first injection), and urinary tract infections. The depletion of CD20+ lymphocytes causes a decrease in immunoglobulin M levels, which does not correlate with the risk of serious infections. The drop in absolute lymphocyte count is temporary, and neutropaenia risk is very low (<1%). So far, no increased risk of associated malignancies has been identified for ofatumumab. All disease-modifying therapies approved for multiple sclerosis exert complex effects on immune system function; thus, potential adverse events may be unpredictable. Therefore, active monitoring of multiple sclerosis patients subject to immune therapies, including ofatumumab, remains essential. This applies to patients in open-label extension studies, as well as patients in real-world clinical settings.

multiple sclerosis, safety, disease-modifying therapy, relapsing multiple sclerosis, ofatumumab