Positive results from Trius torezolid Phase 1 lung study

Trius Therapeutics, Inc. (Nasdaq:TSRX) today announced results from its Phase 1 clinical trial to evaluate the ability of torezolid to penetrate into the lung for potential use to treat lung infections. In this study a 200 mg dose of torezolid phosphate was administered orally once-daily for three days to healthy adult volunteers. The trial achieved its primary goal of establishing the steady-state plasma pharmacokinetics and distribution of active drug into epithelial lining fluid (ELF). The same 200 mg once-daily dose of torezolid phosphate is currently being tested in a Phase 3 clinical trial for acute bacterial skin and skin structure infections (ABSSSI).

In the Phase 1 lung study, the exposure of torezolid in ELF was 48-fold higher than that achieved in plasma. This exposure was significantly above the minimum inhibitory concentration, MIC(90), for both Staphylococcus aureus (0.50 ug/mL) and Streptococcus pneumoniae (0.25 ug/mL) for the full daily dosing interval providing a pharmacokinetic rationale for the administration of a single 200 mg dose of torezolid phosphate every 24 hours for the treatment of lung infections caused by these pathogens. These results are consistent with those of prior animal studies that demonstrated considerable penetration of torezolid into lung fluids and tissues which translated into high efficacy in lung infections due to S. pneumoniae (penicillin-susceptible and -resistant) and S. aureus (methicillin-susceptible and -resistant) pathogens.

"Antibiotic penetration to the site of infection is a prerequisite for the effective treatment of pneumonia and this study clearly establishes that torezolid phosphate at the current 200 mg once-daily therapeutic dose is able to achieve a target exposure of drug expected to effectively treat lung infections," said Dr. David P. Nicolau, Principal Investigator of the study from the Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT. "The exposure ratio of torezolid into the ELF versus plasma was above values reported for linezolid, the first generation oxazolidinone, as well as above those reported for quinolone antibiotics, such as levofloxacin which is a mainstay of therapy for community and hospital acquired pneumonia."

Jeffrey Stein, President and Chief Executive Officer of Trius, further commented, "These data further support our objective of expanding the development of torezolid phosphate for lung infections caused by Staphylococcus and Streptococcus bacterial pathogens. If successfully developed, we expect torezolid phosphate to be the only once-a-day, gram positive agent for lung infections administered at the same IV and oral dose. We plan to submit, and expect to present, the full results of the study at a major scientific conference later this year."