Berkeley, CA and Basel, Switzerland - January 8, 2009 -- Plexxikon Inc. and Roche (SWX:ROG), today announced that they have entered into an agreement to develop and commercialize a second novel kinase inhibitor, PLX5568. The main focus of this partnership will be the development of this small molecule inhibitor of Raf kinase as an oral therapeutic treatment for polycystic kidney disease (PKD). There is currently no registered treatment for PKD which affects over 600,000 patients in the U.S and is the most common life- threatening genetic disease.