(SIK-syoo-TOO-myoo-mab)A substance being studied in the treatment of some types of cancer. It is a monoclonal antibody that is made in the laboratory and can bind to substances in the body. Cixutumumab blocks the action of a protein needed for cell growth and may kill cancer cells. It is a type of insulin-like growth factor-1 receptor (IGF-1R) inhibitor. Also called IMC-A12.