Rib-X Pharmaceuticals, Inc. is a product-driven small-molecule drug discovery and development company focused on developing and commercializing antibiotics to treat highly-resistant bacterial infections. Based in New Haven, Connecticut, the Company has raised over $170 million and has two programs, delafloxacin and radezolid, in advanced clinical trials. In addition, a preclinical program featuring an entirely new class of broad-spectrum antibiotics with the potential to treat even highly- resistant Gram-negative infections is scheduled to begin clinical trials in 2011.

Rib-X designs and develops novel small-molecule antibiotics by leveraging the Company's Nobel Prize- winning discovery platform to perform structure-based design and optimization. While many commercially valuable classes of antibiotics bind to the bacterial ribosome, including oxazolidinones, tetracyclines and macrolides, traditional antibiotic discovery relies heavily on serendipity. Rib-X's key competitive advantage is its proprietary understanding of ribosome structure, which enables it to generate antibiotics that overcome known resistance mechanisms and have broad-spectrum activity.

Rib-X's integrated research strategy combines state-of-the-art, proprietary computational analysis, X-ray crystallography, medicinal chemistry, microbiology and biochemistry, thereby allowing Rib-X to rapidly synthesize new agents designed to avoid typical antibiotic resistance mechanisms. Rib-X's iterative intelligent engine has yielded several distinct new antibiotic classes.