CHICAGO, Sept. 19 Targanta Therapeutics Corporation todayreleased detailed data from completed studies comparing the in vitro activityof its lead antibiotic drug candidate, oritavancin, to that of otherantibiotics against a variety of susceptible and resistant strains of gram-positive bacteria. Results are being presented today at the 47th AnnualInterscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)taking place in Chicago, IL. All posters highlighted below are beingpresented at 12:15 pm CDT.
Poster E-1617 is entitled "In Vitro Activity Profile of Oritavancin (ORI)Against Resistant Staphylococcal Populations From a Recent SurveillanceInitiative." In this study, researchers examined clinical isolates ofStaphylococcus aureus (n=5,008) and coagulase-negative staphylococci (n=862)collected in 2005-2006 from hospital sites in the U.S., Europe and Israel.Oritavancin was active against all staphylococcal isolates, including thosewith specific resistance phenotypes and including multi-drug resistant S.aureus, which were resistant to three or more of the following agents:ciprofloxacin, clindamycin, erythromycin, gentamicin, oxacillin, quinupristin-dalfopristin, trimethoprim-sulfa, vancomycin, daptomycin, and linezolid.Results from this study demonstrated that oritavancin had potent in vitroactivity against a wide spectrum of staphylococci likely to be encountered ina variety of clinical settings.
Poster E-1613, entitled "In Vitro Activity Profile of Oritavancin (ORI)Against Organisms Demonstrating Key Resistance Profiles to Other AntimicrobialAgents," compared the activity of oritavancin to vancomycin and teicoplaninagainst a diverse collection of staphylococci and enterococci, includingstrains with elevated MICs to linezolid, daptomycin, and/or vancomycin, aswell as strains of streptococci. Bacterial isolates included S. aureus(n=35), coagulase-negative staphylococci (n=21), Enterococcus faecalis (n=11),Enterococcus faecium (n=32), Streptococcus pneumoniae (n=20) and Streptococcuspyogenes (n=20). Data from the study revealed that oritavancin demonstratedpotent in vitro activity against geographically diverse, contemporary gram-positive pathogens with important resistance phenotypes and genotypes.
The study presented in poster E-1615, entitled "Anti-Enterococcal ActivityProfile of Oritavancin, a Potent Lipoglycopeptide under Development for UseAgainst Gram-Positive Infections," established a current in vitro activityprofile of oritavancin against both E. faecalis and E. faecium populations,including strains resistant to linezolid, daptomycin, and vancomycin. In thestudy, oritavancin showed potent in vitro activity against all enterococciencountered in this study, including strains non-susceptible to vancomycin(both VanA and VanB phenotypes), linezolid or daptomycin.
Poster E-1619, entitled "Synergistic Effects of Oritavancin Tested inCombination with Other Agents," details a study that tested for synergisticactivity of oritavancin when combined with other antibiotics against S. aureusand enterococci of different resistance phenotypes. Oritavancin was tested incombination with daptomycin, gentamicin, linezolid, moxifloxacin or rifampicinagainst methicillin-sensitive S. aureus (MSSA), a clinical isolate ofvancomycin-intermediate S. aureus (VISA), vancomycin-resistant S. aureus(VRSA), vancomycin-resistant E. faecium (VanA VRE), and vancomycin-resistantE. faecalis (VanB VRE). The study demonstrated that oritavancin has promisingactivity in vitro in combination as it synergizes with antibiotics ofdifferent classes against gram-positive pathogens of clinically importantresistance phenotypes.
In poster E-1620, entitled "Pharmacokinetic Concentrations of OritavancinKill Stationary-Phase and Biofilm Staphylococcus aureus In Vitro," researchersdetailed the antibacterial efficacy of physiologically attainableconcentrations