A humanized monoclonal antibody directed against insulin-like growth factors 1 and 2 (IGF-1/2) with potential antineoplastic activity. Anti-IGF1/2 monoclonal antibody MEDI-573 inhibits IGF1- and IGF2-stimulated activation of membrane-bound IGF receptors and the subsequent triggering of proliferation and survival signaling pathways. This may result in the inhibition of tumor cell proliferation and the induction of tumor cell apoptosis. IGF1/2 ligands stimulate cell proliferation, enable oncogenic transformation, and suppress apoptosis; IGF1/2 signaling has been highly implicated in tumorigenesis and metastasis.