Dr. Walker served as President and Chief Scientific Officer of Brickell Biotech, Inc. a pharmaceutical company, from June 2015 to November 2018. In addition, Dr. Walker previously served in multiple roles at Kythera Biopharmaceuticals, a biopharmaceutical company, from 2008 to 2015, including Chief Medical Officer, and in multiple roles at Allergan plc, a pharmaceutical company, from 1997 to 2004 and 2006 to 2007, including Executive Vice President and Chief Scientific Officer, and was Executive Vice President and Chief Scientific Officer at Inamed Corporation, a healthcare products manufacturer, from 2004 to 2006. Dr. Walker is currently a supervisory board member of Merz Pharma, a pharmaceutical company. Dr. Walker received a M.D. and Ph.D. from the University of Iowa College of Medicine and a B.S. from the University of Iowa.