Jack Lief is a co-founder of Arena and has served as a director and our President and Chief Executive Officer since April 1997. Mr. Lief has also served as the Chairman of our Board of Directors since October 2007. Mr. Lief served as an advisor and consultant to numerous biopharmaceutical organizations from 1995 to April 1997; as Senior Vice President, Corporate Development and Secretary of Cephalon, Inc., a biopharmaceutical company, from 1989 to 1994; as Director of Business Development and Strategic Planning for Alpha Therapeutic Corporation, a manufacturer of biological products, from 1983 to 1989; and in various positions at Abbott Laboratories, a pharmaceutical company, from 1972 to 1983, most recently as the head of International Marketing Research. Mr. Lief serves as the Chairman of the board of directors of ADVENTRX Pharmaceuticals, Inc., a company focused on pharmaceuticals for cancer and infectious disease. Mr. Lief is also an Executive Board Member of BIOCOM, a life science association representing approximately 550 member companies in Southern California, and was the Chairman of the board of directors of BIOCOM from March 2005 to March 2006. Mr. Lief holds a B.A. from Rutgers University and an M.S. in Psychology (Experimental and Neurobiology) from Lehigh University.

K.A. Ajit-Simh has served as our Vice President, Quality Systems since January 2004. Mr. Ajit-Simh provided regulatory compliance services to several companies in the United States and internationally from 1999 to 2003. Mr. Ajit-Simh held various positions of increasing responsibility at Cytel Corporation, a biotechnology company, from 1992 to 1999; Abbott BioTech, a health products company, from 1989 to 1992; Baxter Healthcare, a health products company, from 1986 to 1989; and Mallinckrodt Inc., a pharmaceutical/chemical company, from 1975 to 1985. In addition, Mr. Ajit-Simh has been an instructor at the University of California, San Diego since 1994, teaching classes in regulatory compliance and quality control/assurance. Mr. Ajit-Simh also teaches courses in Good Manufacturing Practices and Advanced Quality Control and Assurance at San Diego State University as part of the graduate program in Regulatory Affairs. Mr. Ajit-Simh received a B.Sc. degree in Biology and Chemistry from Bangalore University and an M.S. in Cell Biology from St. Louis University.

Dominic P. Behan, Ph.D., is a co-founder of Arena and has served as a director since April 2000, and as our Senior Vice President and Chief Scientific Officer since June 2004. Dr. Behan served as our Vice President, Research from April 1997 to June 2004. Dr. Behan directed various research programs at Neurocrine Biosciences, Inc., a biopharmaceutical company, from 1993 to 1997, and was engaged in research at the Salk Institute from 1990 to 1993. Dr. Behan holds a B.Sc. in Biochemistry from Leeds University, England, and a Ph.D. in Biochemistry from Reading University, England.

Robert E. Hoffman has served as our Vice President, Finance and Chief Financial Officer since December 2005. Mr. Hoffman served as our Vice President, Finance and Chief Accounting Officer from June 2004 to December 2005, as our Vice President, Finance from April 2000 to June 2004, and as our Controller from August 1997 to April 2000. Mr. Hoffman served as Assistant Controller for Document Sciences Corporation, a software company, from 1994 to 1997. Mr. Hoffman serves as a member of the Financial Accounting Standards Board's small business advisory committee, the steering committee of the Association of Bioscience Financial Officers and as a supervisory committee member of the San Diego County Credit Union. Mr. Hoffman is also a director and a former President of the San Diego chapter of Financial Executives International. Mr. Hoffman holds a B.B.A. from St. Bonaventure University, and is licensed as a C.P.A. (inactive) in the State of California.

William R. Shanahan, Jr., M.D., J.D., has served as our Vice President and Chief Medical Officer since March 2004. Dr. Shanahan served as Chief Medical Officer for Tanox, Inc., a biopharmaceutical company, from 2000 to March 2004; in various positions at Isis Pharmaceuticals, Inc., a biopharmaceutical company, from 1994 to 2000, most recently as Vice President, Drug Development; as Director, Clinical Research for Pfizer Central Research, a pharmaceutical company, from 1989 to 1994; and in various positions at Searle Research & Development, a pharmaceutical company subsequently acquired by Pfizer, from 1986 to 1989, most recently as Director, Clinical Research. Dr. Shanahan holds an A.B. from Dartmouth College, an M.D. from the University of California, San Francisco and a J.D. from Loyola University, Chicago.

Steven W. Spector, J.D., has served as our Senior Vice President and General Counsel since June 2004. Mr. Spector served as our Vice President and General Counsel from October 2001 to June 2004. Mr. Spector has also served as our Secretary since November 2001. Prior to joining Arena, Mr. Spector was a partner with the law firm of Morgan, Lewis & Bockius LLP, where he worked from 1991 to October 2001, and was a member of the Morgan Lewis Technology Steering Committee. Mr. Spector was our outside corporate counsel from 1998 to October 2001. Mr. Spector is a member of the board of directors and a former President of the Association of Corporate Counsel, San Diego. Mr. Spector holds a B.A. and a J.D. from the University of Pennsylvania.