Jonathan Leff
Partner
Warburg Pincus LLC

Mr. Leff has served as a member of our Board since January 2000. Mr. Leff joined Warburg Pincus LLC in 1996 and is currently a managing director. Mr. Leff serves on the Board of Directors of Transkaryotic Therapies, Inc., Synaptic Pharmaceutical Corp., and Zymogenetics, Inc., all of which are publicly held biotechnology companies. Mr. Leff holds an M.B.A. from Stanford University.