Optimer Pharmaceuticals Inc.

Michael N. Chang is a co-founder of Optimer and has served as our President and Chief Executive Officer since our inception in November 1998. Before joining Optimer, Dr. Chang was the Chief Scientific Officer of NuSkin Enterprises, Inc., a NYSE listed direct selling company based in Utah. Dr. Chang joined NuSkin Enterprises upon its acquisition of Pharmanex, Inc., a natural healthcare company, which he co-founded and where he was employed since January 1995 as Senior Vice President, Research and Development and Chief Science Officer. Dr. Chang was also a co-founder of Pharmanex, which was purchased by Nu Skin Enterprises in 1998. Before Pharmanex, Dr. Chang worked for 15 years in the pharmaceutical industry, at Merck & Co, Inc., a publicly traded research driven pharmaceutical company, Rhone-Poulenc Rorer Inc., which is now Sanofi-Aventis, a publicly-traded pharmaceutical company, and ArQule, Inc., a development stage oncology company. Dr. Chang holds 35 US patents and more than 60 publications. He received a B.S. degree in chemistry from Fu-Jen University in Taiwan, a Ph.D. degree in organic chemistry from Brandeis University and post- doctoral training at the Massachusetts Institute of Technology, or MIT.

John D. Prunty, C.P.A. has served as our Chief Financial Officer and Vice President Finance since June 2006. Before joining us, Mr. Prunty held several key positions with Maxim Pharmaceuticals, Inc., a biopharmaceutical company, for six years, including Chief Financial Officer, Vice President of Finance, and Corporate Secretary. Prior to his employment at Maxim, Mr. Prunty served as Senior Director of Finance and Corporate Controller at Gen Probe Incorporated, a manufacturer of nucleic acid tests that diagnose human diseases, from 1997 to 2000. He also held senior management positions at I-Bus, currently known as I-Bus/Phoenix, Inc., a division of Maxwell Laboratories, Inc., an electronic device company. Mr. Prunty began his career as an auditor at Ernst & Young LLP, an accounting firm, where he spent seven years in public accounting. He is a certified public accountant and received a B.B.A. from the University of San Diego and an M.S. in management from San Diego State University.

Sherwood L. Gorbach, M.D. has served as our Senior Vice President, Chief Medical Officer since November 2005. Since 1975, Dr. Gorbach has been at Tufts University School of Medicine serving as, among other things, a Professor of Family Medicine and Community Health and a Professor in the School of Nutrition and Social Policy. Dr. Gorbach also served as Chief of Infectious Diseases at New England Medical Center from 1975 to 1987. In 1990, he served as the President of the Massachusetts Infectious Diseases Society, and in 1995, he was the President of the Society of Microbial Ecology and Disease. In 2007, Dr. Gorbach received the Alexander Fleming Award for Lifetime Achievement, Infectious Diseases Society of America. Dr. Gorbach is a renowned authority on infectious diseases and Editor-in-Chief of the journal, Clinical Infectious Diseases. Dr. Gorbach received his M.D. at the Tufts University School of Medicine in Boston.

Tessie M. Che, Chief Operating Officer and Senior Vice President, Corporate Affairs, has been with Optimer since November 1999. Dr. Che has over 20 years of industrial and management experience at large companies including Exxon Mobil Corporation, a petroleum and petrochemical company, Aventis Pharmaceuticals, Inc., a pharmaceutical company, and EniChem S.p.A., a chemical company. Prior to joining Optimer, Dr. Che served as the Chief Operating Officer and Vice President of the M and D Precision Science Group, Inc., a biotechnology company. In 1994, Dr. Che also co-founded and headed Zhejiang Cinogen Pharmaceutical Co., Ltd., a pharmaceutical company, which later merged with and became a wholly-owned subsidiary of Pharmanex, Inc. At Pharmanex, she served as Director of Quality Assurance and Senior Director of Ingredient Sourcing from 1995 to 1999. Dr. Che has numerous scientific publications as well as 18 U.S. patents in material synthesis and application. She received her B.S. degree in chemistry from Illinois State University, a Ph.D. in physical-inorganic chemistry from Brandeis University and did post doctoral work at Columbia University.

Since January 2006, Mr. Auerbach has been the Chairman of the Board of Directors, and a member of the Compensation Committee and Audit Committee. Since September 2003, Mr. Auerbach has served as Executive Chairman of the Board of Directors of Par Pharmaceuticals, and as a Director of Optimer Pharmaceuticals, Inc. From June 1993 through December 2005, Mr. Auerbach served as Senior Vice President and Chief Financial Officer of Central Lewmar L.P.