BOARD OF DIRECTORS

Mark Leschly has served as a member of our board of directors since September 1996. Since July 1999, Mr. Leschly has been a Managing Partner with Rho Capital Partners, an investment and venture capital management company. Starting in July 1994 to July 1999, Mr. Leschly was a principal and then a General Partner of HealthCare Ventures, L.L.C., a venture capital management company. From September 1991 to June 1993, Mr. Leschly served as a consultant for McKinsey & Co., a management consulting company. He also serves as a director of Diversa Corporation, Tercica, Inc. and Senomyx, Inc., each biotechnology companies. Mr. Leschly holds a B.A. degree from Harvard University and an M.B.A. from the Stanford Graduate School of Business.