Information about Ofatumumab
Liver safety of Ofatumumab
Ofatumumab therapy has not been associated with serum enzyme elevations during therapy or to cases of idiosyncratic, clinically apparent liver injury. However, ofatumumab has potent immunosuppressive activity and its use has been associated with cases of reactivation of inactive or previously resolved hepatitis B which can be severe and can result in fatality.
Mechanism of action of Ofatumumab
Ofatumumab (oh” fa toom’ ue mab) is a human monoclonal IgG1 antibody to the cell surface antigen CD20 (also known as human B lymphocyte restricted differentiation antigen: Bp35), which is found on mature B cells as well as 90% of neoplastic B cell such as occur in chronic lymphocytic leukemia. CD20 is not present on pro-B cells, hematopoietic stem cells, normal plasma cells or other normal lymphocytes, circulating cells or tissues. Engagement of ofatumumab with CD20 leads to B cell lysis and depletion of circulating and tissue B cells for an extended period, up to 6 to 8 months. There is an accompanying mild decrease in IgM, but no change in IgG or IgA levels.
FDA approval information for Ofatumumab
Ofatumumab was approved for use in previously treated, resistant chronic lymphocyte leukemia United States in 2009.
Dosage and administration for Ofatumumab
Ofatumumab is available in liquid solution in single use vials of 100 and 1000 mg (20 mg/mL) under the brand name Arzerra. The dose and regimen varies by indication, but it is usually given intravenously in 300 to 2000 mg amounts in 28 day cycles.
Side effects of Ofatumumab
Common side effects include infusion reactions, chills, fever, nausea, diarrhea, fatigue, dyspnea, cough, bronchitis, pneumonia, skin rash, neutropenia and infections. Less common, but potentially severe side effects include cutaneous reactions (Stevens Johnson syndrome), tumor lysis syndrome, prolonged neutropenia, thrombocytopenia and anemia. Because of the potential severity of infusion reactions, premedication with antihistamines, acetaminophen and corticosteroids is recommended, and ofatumumab should be administered under close medical observation.