FebFebruary 6. 2003

FOR IMMEDIATE RELEASE

Rib-X Pharmaceuticals Names Graham Johnson, Ph.D. As Vice President of Discovery

NEW HAVEN, Conn., Rib-X Pharmaceuticals, Inc., a privately held bioscience company focused on the discovery of new anti-infectives, today announced that Graham Johnson, Ph.D., has been appointed to the newly created position of Vice President of Discovery. Dr. Johnson will report to Dr. Susan Froshauer, President and Chief Executive Officer of Rib-X."We are very excited that Dr. Johnson brings more than 25 years of drug discovery experience to Rib-X, along with an established track record of generating diverse clinical candidates," said Dr. Froshauer. "Graham is joining Rib-X at an important juncture in our Company's evolution as we move our science closer to the clinic. We have succeeded in assembling a team that includes some of the greatest minds in the field of anti-infective research, and our timeframe is firmly on target for the nomination of a clinical candidate this year."Dr. Johnson comes to Rib-X from Bristol-Myers Squibb (BMS), where his 12-year tenure included positions such as Vice President of Discovery Chemistry for the company's Wallingford, Connecticut facility, and Interim Vice President of Neuroscience Biology. Under his leadership, Wallingford Discovery Chemistry generated numerous high quality clinical candidates nominated from diverse areas of discovery. In addition, Dr. Johnson served as a core member of numerous senior leadership governance committees for BMS. Before joining BMS in 1991, Dr. Johnson was with Warner-Lambert/Parke-Davis, where he was jointly responsible for defining and implementing drug discovery strategies for three CNS related project teams. At the conclusion of his nine-year tenure, Dr. Johnson held the position of Director of Neuroscience Chemistry and was serving as the Co-Chairperson of the Cognition and Neurological Disorders Drug Discovery Teams. Dr. Johnson began his industrial career in 1978 with Hoechst UK, Ltd., where he was one of two senior scientists responsible for developing the penem antibiotic program. Dr. Johnson is named as an inventor on more than 50 U.S. patents and has co-authored more than 50 published scientific papers. Born and educated in England, Dr. Johnson received his university education (B.Sc. and Ph.D.) from Heriot-Watt University in Edinburgh, Scotland. In 1975 he was awarded a Fulbright Senior Scholarship for Postdoctoral study in the United States. Dr. Johnson completed his university education with postdoctoral research with Professor Jack Baldwin at M.I.T., and Professor Sir. Derek Barton at Imperial College in London and later at the Research Institute for Medicine and Chemistry in Cambridge, Mass.

Rib-X Pharmaceuticals is a small molecule drug discovery company focused on the structure-based design of new classes of anti-infective agents. The company's drug discovery strategy is focused on the exploitation of its proprietary high resolution crystal structure of the 50S subunit of the ribosome, to which known antibiotics bind. The company's integrated research approach combines computational analysis, x-ray crystallography, medicinal chemistry, microbiology and biochemistry, allowing for the rapid synthesis of new agents, which avoid typical antibiotic resistance mechanisms. Utilizing its proprietary software and intellectual property, Rib-X expects to quickly optimize leads to create a new class of antibiotics.

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