SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)-- Exelixis, Inc. (Nasdaq:EXEL) announced today that it has submitted an investigational new drug (IND) application to the U.S. Food and Drug Administration for XL888, a novel anticancer compound. XL888 is an orally available small molecule inhibitor of HSP90, which is a chaperone protein that promotes the activity and stability of a range of key regulatory proteins, including kinases. The activity of HSP90 is particularly prominent in tumor cells where it promotes the activity of proteins controlling growth and survival.