October 19, 2006

FOR IMMEDIATE RELEASE

Dr. Susan Froshauer, President and Chief Executive Officer of Rib-X Pharmaceuticals, will present at the The BIO InvestorForum 2006

San Francisco- Rib-X Pharmaceuticals, Inc. is a product-driven small molecule drug discovery and development company focused on the structure-based design of new classes of antibiotics. The company's underlying drug discovery engine capitalizes on its proprietary high-resolution crystal structure of the 50S subunit of the ribosome, which performs an essential role in the fundamental process of protein synthesis. Many known, commercially valuable antibiotics bind to the 50S, including those used to treat both community-acquired and hospital-acquired pathogens. The company's integrated research strategy, which combines state of the art, proprietary computational analysis, x-ray crystallography, medicinal chemistry, microbiology and biochemistry, allows it to rapidly synthesize new agents designed to avoid typical antibiotic resistance mechanisms. Rib-X's iterative intelligent engine has yielded several distinctive new antibiotic classes. Its most advanced program, the Rx- 01 program is in Phase I as an oral/IV agent to treat serious hospital- Gram- positive infections. To further build on their pipeline, the company recently in-licensed a Phase II quinolone antibiotic from Wakunaga Pharmaceutical Company, Ltd. For more information on the company, the ribosome and the Rib-X mission, please visit the company website at www.rib-x.com.

For Additional Information:

Rx Communications Group
Rhonda Chiger
917-322-2569