Rib-X Pharmaceuticals to demonstrate three presentations at Antibacterial Drug Development Conference

Rib-X Pharmaceuticals, Inc., a development-stage antibiotics company with a broad product pipeline based on its innovative discovery platform, today announced that it will be presenting three separate presentations at the Cambridge Healthtech Institute's 4^th Annual Antibacterial Drug Development Conference, Resistance is Futile: The Challenge of Antibacterial Drug Development, April 27 - 28, in San Diego, CA. The presentations include overviews on delafloxacin, radezolid and the Company's proprietary platform for unlocking the bacterial ribosome, which has allowed for the design and generation of three novel classes of antibiotics that have been tuned for both multi-drug resistant Gram-negative and Gram-positive activity and have shown efficacy in multiple animal models of infection.

Presentations, April 27, 2010

• 9:20 A Novel Oxazolidinone with Enhanced Efficacy Due to Intracellular Accumulation
  Andrea Marra, Ph.D., Associate Director, Preclinical Development, Rib-X Pharmaceuticals, Inc.
  This presentation will focus on radezolid, an oxazolidinone that was discovered using our proprietary structure-based drug design approach. The properties of this drug will be highlighted, in particular its ability to accumulate inside cells, and how this impacts efficacy in preclinical infection models.

• 11:15 Delafloxacin: A Broad Spectrum Quinolone with Coverage Against MRSA
  Andrea Marra, Ph.D., Associate Director, Preclinical Development, Rib-X Pharmaceuticals, Inc.
  The distinguishing properties of delafloxacin will be discussed, including its in vitro potency, efficacy in preclinical models of infection, and how it will fit in the clinic.

• 2:30 Quest for the Broadest Spectrum Antibiotic
  Zoltan Kanyo, Ph.D., Associate Director, Structure-Based Drug Design, Rib-X Pharmaceuticals, Inc.
  This talk will highlight how a detailed understanding of how antibiotics bind to the bacterial ribosome coupled with insights on molecular features that drive bacterial membrane permeability have fueled the design and optimization of three completely new series of antibiotics with broad-spectrum activity and efficacy in animal models of infection.