September 9, 2002

FOR IMMEDIATE RELEASE

Rib-X Pharmaceuticals Opens New State-of-the-Art Facility -

Relocation to Support Drug Discovery Paradigm and Expansion of Staff -

New Haven Mayor John DeStefano, Jr. to Attend Opening Celebration -

NEW HAVEN, Conn.,- Rib-X Pharmaceuticals, Inc., a privately held bioscience company focused on the discovery of new anti-infectives, today announced the relocation of the company's corporate headquarters and research operations to a new facility in The George Street Technology Center, located at 300 George Street in New Haven. Mayor John DeStefano, Jr. is expected to attend the opening celebration, which will be held at the new facility on Tuesday, September 10, 2002 from 4 pm - 6 pm (EDT).

"The design of the new space allows us to implement our integrated, structure-based drug design approach by bringing biochemistry, microbiology, crystallography, computation and chemistry together to form the optimal drug discovery environment," said Dr. Susan Froshauer, the President and CEO of Rib-X. "As we move towards the clinical process, Rib-X is in a heavy growth mode. We have hired more than 40 people during the past year, with plans for at least 20 more by year's end. Our expansion is fueling the development of a true heterogeneous community as we attract staff from countries such as Germany, Switzerland and Nigeria, and all areas of the United States."

The build-out for the 27,000 square-foot facility was largely funded by Connecticut Innovations, one of the State's leading investors in high technology. Rib-X management worked directly with the owner and manager of The George Street Technology Center, Winstanley Enterprises, LLC of Concord, Massachusetts, in securing the space and negotiating the lease. The George Street Technology Center is home to numerous other biotechnology companies.

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.

Contacts:
Rx Communications Group
Rhonda Chiger (investors)
917-322-2569
rchiger@rxir.com

Pete Holmberg (media)
917-322-2164
pholmberg@rxir.com