Exelixis has submitted an IND application to the FDA for XL147, a novel anticancer compound. XL147 is an orally available small molecule inhibitor of phosphoinositide-3 kinase (PI3K). Activation of PI3K is a frequent event in human tumors, promoting tumor cell growth, survival, and resistance to chemotherapy and radiotherapy. “A growing body of data indicates that inappropriate activation of the PI3K signaling pathway is a common feature of human tumors and may result from dysregulation...