Michael D. Casey has served as a Director since March 2004. Mr. Casey was Chairman, President and Chief Executive Officer of Matrix Pharmaceuticals, Inc. from September 1997 until February 2002 when Matrix was acquired by Chiron Corporation. From November 1995 until September 1997, Mr. Casey was President, Retail and Specialty Products Divisions of Schein Pharmaceutical, Inc. Mr. Casey was President and Chief Operating Officer of Genetic Therapy, Inc. from June 1993 until November 1995. Mr. Casey held various positions at Johnson & Johnson companies over a twenty-five year period, including serving as President of McNeil Pharmaceutical from July 1989 to June 1993. Mr. Casey is currently a director of a number of biotechnology and pharmaceutical companies including Celgene Corporation, Allos Therapeutics, Inc., and AviBio Pharma, Inc.