Ibritumomab tiuxetan (Zevalin) and elevated serum human anti-murine antibody (HAMA)

Abstract Ibritumomab Tiuxetan (Zevalin) is an anti CD-20 murine monoclonal antibody linked to the radio-isotope 90-yttrium (90Y) by the chelator Tiuxetan. It is FDA approved for treatment of relapsed low grade or follicular B-cell Non-Hodgkin's Lymphoma (NHL) or newly diagnosed follicular NHL following an initial response to first-line chemotherapy. Patients may develop Human Anti-Murine Antibodies (HAMA), following exposure to murine antibodies. There is a concern for development of hypersensitivity reactions with Ibritumomab, especially in patients with an elevated HAMA titer. Here we describe a case of a 66 year old male with elevated HAMA titer successfully treated with Zevalin without any hypersensitivity reactions. Existing literature supports our observation that Zevalin can be safely used in most patients with elevated HAMA titers.