Tetraphase Pharmaceuticals Announces Appointment of Guy Macdonald as President and Chief Executive Officer

Tetraphase Pharmaceuticals, Inc.

Tetraphase Pharmaceuticals Announces Appointment of Guy Macdonald as President and Chief Executive Officer

April 9, 2008

Industry Veteran to Lead Advancement of Company’s Breakthrough, Synthetic Chemistry Platform

WATERTOWN, Mass.--(BUSINESS WIRE)--Tetraphase Pharmaceuticals Inc., announced today that the Board of Directors has appointed Guy Macdonald, BSc, as the Company’s first President and CEO. A 25-year veteran of the global pharmaceutical and biotechnology sector, Mr. Macdonald will lead Tetraphase’s drug discovery and development programs, capitalizing on the Company’s breakthrough synthetic chemistry platform.

Formed in 2006, Tetraphase was established to advance and commercialize the ground-breaking synthetic chemistry platform developed by internationally-recognized chemist Professor Andrew G. Myers, Ph.D., Chair, Department of Chemistry and Chemical Biology at Harvard University. Tetraphase’s initial focus is on the discovery and development of novel antibiotics to treat drug-resistant infections. The Company’s enabling technology also opens up important opportunities in inflammation and cancer. The Company completed a successful $25.0 million Series A financing in 2006. The Series A round was funded by leading healthcare venture capital investors Mediphase Venture Partners, CMEA Ventures, Fidelity Biosciences, Flagship Ventures and Skyline Ventures.

“The board of directors is delighted that Guy Macdonald has accepted the opportunity to lead Tetraphase at this important point in its evolution,” stated Lawrence Miller, M.D., Chairman of Tetraphase. “Guy has extensive experience in drug development, in particular with anti-infectives. His superb track record in global pharmaceuticals and biotechnology will be invaluable as we pursue the development of novel drugs across a broad spectrum of disease categories.”

Mr. Macdonald joins Tetraphase from Idenix Pharmaceuticals, where he served as Executive Vice President and Chief Operating Officer. In this position, he oversaw the development of Idenix’s commercial organization in the U.S. and the top five EU countries. In addition, he was responsible for regulatory affairs, quality assurance, manufacturing, information technology and project management.

Mr. Macdonald previously spent twenty-two years at Merck & Co., where he served as a senior leader in the areas of virology and anti-infectives and was involved in several landmark launches at a global level. Among his positions at Merck, he was Vice President for Anti-Infective and Hospital Products, with sales of more than $1.4 billion.

Mr. Macdonald received an Honours Degree in Biochemistry from Dundee University, Dundee, Scotland.

About Tetraphase Pharmaceuticals Inc.

Tetraphase Pharmaceuticals is capitalizing on breakthrough synthetic chemistry technology for drug discovery and development based on a process developed by world leading organic chemist Dr. Andrew Myers of Harvard University. This enabling advance in chemistry provides the company with a broad-range of commercial opportunities across a number of significant disease categories.

Contacts

Tetraphase Pharmaceuticals Inc.
David Lubner, 617-715-3551
Sr. Vice President and Chief Operating Officer