SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)--Exelixis, Inc. (NASDAQ: EXEL) announced today that it will hold two investor briefings in conjunction with the American Society of Clinical Oncology (ASCO) Annual Meeting from 6:30 p.m. to 8:00 p.m. CDT on Saturday, June 5, 2010 and 6:00 p.m. to 7:30 p.m. CDT on Monday, June 7, 2010.