Daiichi Sankyo Co. has entered an agreement to acquire Plexxikon, Inc. for $805 million up-front, with milestone payments associated with the approval of PLX4032 totaling an additional $130 million. The transaction is subject to customary closing conditions. Plexxikon’s lead program is PLX4032 is an oral drug that targets the oncogenic BRAF mutation present in about half of melanoma cancers and about 8% of all solid tumors. Plexxikon and development partner, Roche, plan to file for market ap...