Resistant to traditional antibiotics, “superbugs” such as MRSA are a growing problem in both hospital and community settings. Rib-X Pharmaceuticals, Inc. is focused on the design and development of novel small-molecule antibiotics for the treatment of antibiotic-resistant infections in such environments.

Detailing the Rib-X story Feb 12 in New Haven, as part of the BioHaven seminar series presented by CURE and Yale OCR, were Bob Conerly, vice president and CFO, and Erin Duffy, Ph.D., vice president, structure based drug design. The team was introduced by Michelle Bowman of series sponsor PricewaterhouseCoopers.

	Erin Duffy and Bob Conerly of Rib-X Pharmaceuticals

Since its inception in 2001, Rib-X has established a portfolio of development and discovery-stage compounds that address various segments in the diverse antibiotic marketplace, including RX-3341, a broad spectrum quinolone antibiotic which will soon enter Phase 3 studies as an IV agent and RX-1741, an oxazolidinone antibiotic now in two Phase 2 studies as an oral agent.

Many classical antibiotics work by inhibiting the function of the ribosome. A key competitive advantage, Rib-X maintains, is its proprietary access to the high-resolution crystal structure of the ribosome, a molecule which is essential for the viability of all bacterial pathogens and the target of numerous valuable antibiotics.

Michelle Bowman, partner, PricewaterhouseCoopers, and Harry Penner, chair, Rib-X Pharmaceuticals

Rib-X's research goal is to use chemical and physical information from the three-dimensional structure of the ribosome to design proprietary classes of antibacterial agents that have activity against newly emerging multiple antibiotic-resistant microorganisms.

Structural and computational data about how ligands block the function of this complex molecular machine are being used to prime parallel lead optimization programs focused on new chemistry ideas about the multiple binding domains or drug targets within the ribosome.

Rib-X raised $50 million in a Series C Preferred Stock financing announced in June of 2006. The round was led by existing investor Warburg Pincus, the global private equity investment firm. That round of financing brought the total amount raised by the company to $123 million.