CUDC-427, also known as, GDC-0917, is an orally available, monovalent mimetic of second mitochondrial-derived activator of caspases (Smac/DIABLO) and inhibitor of IAPs (Inhibitor of Apoptosis Proteins) with potential antineoplastic activity. Smac mimetic CUDC-427 binds to the Smac binding groove on IAPs, including the direct caspase inhibitor X chromosome-linked IAP (XIAP) and the cellular IAPs 1 and 2. This inhibits the activities of these IAPs and promotes the induction of apoptosis through apoptotic signaling pathways.