A human monoclonal antibody that is being used to treat colorectal cancer that has spread to other parts of the body. It is used in patients whose disease has not gotten better during or after treatment with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Panitumumab binds to the epidermal growth factor receptor (EGFR) and may block tumor cell growth. Also called ABX-EGF and Vectibix.