Bristol-Myers Squibb has exercised its option to develop and commercialize Exelixis’ compound XL139. Exelixis will receive a $20 million milestone payment and has exercised its option to co-develop and co-commercialize the drug in the U.S. BMS will lead all global activities and the parties will co-develop and co-commercialize XL139 in the U.S. and split those profits. Exelixis will be entitled to receive royalties on product sales outside of the U.S.     XL139 is a small molecule inhib...