New Haven, Connecticut, Jan. 2, 2002 -- Rib-X Pharmaceuticals, Inc., a bioscience company focused on the discovery of new anti-infectives, today announced that it has raised approximately $22 million in a Series A financing. The company will exploit a proprietary high resolution crystal structure of the ribosome to discover new antibiotic agents. The ribosome performs the essential biological function of protein synthesis, and is the target for many known antibiotics. Rib-X has exclusively licensed the high resolution ribosome structure that was discovered by two of the company's founders, Thomas Steitz, PhD and Peter Moore, PhD, both of Yale University. In addition, the company has exclusive access to breakthrough structure-based drug design software developed by company co-founder William Jorgensen, PhD, also of Yale.

SR One Limited/EuclidSR Partners and Oxford Bioscience Partners served as lead investors for the financing. Other participating investors include ABS Ventures, Axiom Ventures, Cardinal Partners, Connecticut Innovations and Zero Stage Capital. Michael Lytton of Oxford Bioscience Partners and Barbara Dalton, PhD of SR One Limited/EuclidSR Partners have been named to Rib-X's board of directors, bringing the board to five members. Other board members include co-founders John Abelson, PhD of the California Institute of Technology, Harry Penner (chair) former President and Chief Executive Officer of Neurogen Corporation and Susan Froshauer, PhD, President and Chief Executive Officer of Rib-X.

"We founded Rib-X confident in our belief that the key elements of success in drug discovery are a validated chemical space and a validated clinical target,'' stated Dr. Susan Froshauer, President and CEO of Rib-X Pharmaceuticals. "The Steitz and Moore technology both provides a window to the binding of known antibiotics to the ribosome and presents an invaluable opportunity to design multiple new classes of antibiotic agents. Having reached this level of research and development funding with such a high caliber investor base, we are in an optimal position to successfully harness the intellectual richness of the ribosome technology and the collective knowledge of our scientific founders."

"The work of Professors Moore and Steitz in generating the high resolution structure of the ribosome is a scientific tour de force, and when combined with Professor Jorgensen's computational chemistry technology, presented a compelling platform for the establishment of a new antibiotic company" said Michael Lytton, General Partner of Oxford Bioscience Partners. Dr. Barbara Dalton, General Partner of SR One Limited/Euclid SR Partners, further commented, "the Company's technology is not only novel and state-of-the art, but it has the capability of reducing the risk of clinical trial failure and moving viable product candidates through the discovery process more quickly.''

About the Rib-X Technology: Rib-X has exclusive license to the high-resolution crystal structure of the largest area of the bacterial ribosome, its 50S subunit, as well as detailed three-dimensional chemical and physical understanding of how drugs bind to the ribosome. This knowledge, in conjunction with proprietary structure-based drug design software created by Dr. Jorgensen, will be used at Rib-X to discover new classes of anti-infective agents. Jorgensen's software will allow Rib-X to guide the synthesis of novel chemical matter by interpreting the properties of existing drugs and from that interpretation, to design new drugs with improved properties.

About Rib-X Pharmaceuticals, Inc.

In addition to Steitz, Moore and Jorgensen, the scientific founders of Rib-X include Dr. Harry Noller, from the University of California, Santa Cruz and Dr. John Abelson, from the California Institute of Technology. Noller has spent his entire career pursuing studies of the ribosome. He brings to the Rib-X founding team an in-depth understanding of the genetics and biochemistry of ribosome function. Dr. Abelson was a founding scientist at Agouron, and as such brings to Rib-X his experience in guiding structure-based drug discovery programs into the clinic. Since many of the antibiotics that bind to the ribosome interact specifically with RNA, Abelson's scientific expertise in the area of RNA biochemistry contributes a further valuable component to the elite founding team. Dr. Susan Froshauer, the Company's President and Chief Executive Officer was a member of the Strategic Alliances group at Pfizer and was responsible for a suite of platform technology deals, "the Big Four,'' valued at approximately $200 million.

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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