A drug used to keep the body from rejecting kidney transplants. It is also being studied in the treatment of some types of cancer and other conditions. Zenapax binds to receptors for a protein called interleukin-2 (IL-2), which are found on some types of immune cells and cancer cells. This may help suppress the body’s immune response and it may help kill cancer cells. Zenapax is a type of monoclonal antibody.