Replidyne's Investigational Antibacterial Agent REP3123 Prevents Toxin Production in Clostridium...( Poster to be Presented at the 47t...),Health

Poster to be Presented at the 47th Annual Interscience Conference on

Antimicrobial Agents and Chemotherapy

LOUISVILLE, Colo., Sept. 19 /PRNewswire-FirstCall/ -- Replidyne, Inc. (Nasdaq: RDYN) announced today that in preclinical studies, its antibacterial candidate REP3123 is shown to stop the production of destructive intestinal toxins caused by Clostridium difficile (C. difficile) bacteria. C. difficile-associated disease (CDAD), an inflammatory condition caused by potentially lethal toxins that enter and then kill healthy cells in the gut, is a major cause of morbidity among elderly and hospitalized patients. The study results suggest that REP3123 inhibits growth and blocks the production of these disease-causing toxins potentially reducing the severity of, and even preventing, CDAD.

These results will be presented on Thursday, September 20, 2007 at 10:00 AM in Room E253D by Urs Ochsner, Ph.D., Principal Scientist, Microbiology at Replidyne during poster session 229 titled, "New Agents Active Against Clostridium difficile" at the 47th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy held at the McCormick Place conference center in Chicago.

REP3123 is a new narrow spectrum antibacterial agent that in vitro prevents the growth of C. difficile by inhibiting an essential enzyme in the bacterial cell called methionyl tRNA synthetase, which blocks the organism from synthesizing proteins. Methionyl tRNA synthetase is a novel target that has not been previously exploited by antibiotics and REP3123 shows no cross-resistance to currently marketed antibacterial agents. When tested in high density cultures, REP3123 inhibited toxin production at low concentrations (<
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