John Walker has served as chief executive officer of iPierian since February 2009. Most recently, Walker served as chairman and CEO of Novacea, which merged with Transcept Pharmaceuticals in January 2009. Walker has also been executive chairman and principal executive officer of Renovis Inc.; chairman and interim CEO of Guava Technologies, KAI Pharmaceuticals and Centaur Pharmaceuticals; and chairman and CEO of Bayhill Therapeutics. From 1993 to 2001, he was chairman and CEO of Arris Pharmaceuticals and its successor corporation AXYS Pharmaceuticals Inc., and previously was chairman and CEO of Vitaphore Corporation. Walker began his career with American Hospital Supply Corporation, where he last served as President of the American Hospital Company. His many board experiences have included serving as chairman of Signal Pharmaceuticals and Microcide Pharmaceuticals Inc., and a director of Geron Corporation, Discovery Partners Inc., and several other private companies. Walker received a B.A. from the State University of New York at Buffalo and is a graduate of the Advanced Executive Program, J. L. Kellogg Graduate School of Management at Northwestern University. He currently serves on the Board of Directors of Affymax, Inc., Transcept Pharmaceuticals, Inc., and a couple of private companies.