A monoclonal antibody that is being studied in the treatment of refractory B-cell non-Hodgkin lymphoma. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. IMMU-106 binds to the protein CD20, which is found on B cells (a type of immune system cell), and some types of lymphoma cells. Also called hA20 and HCD20.