Exelixis, Inc. has signed an extension of its research collaboration with Bristol-Myers Squibb Co. to develop and commercialize therapies targeted against the Liver X Receptor (LXR), a hormone receptor associated with a variety of cardiovascular and metabolic disorders. The collaboration, established in January 2005 for a period of two years, has been extended through January 2009. BMS also has retained the option to further extend the research collaboration an additional year. Under the te...