TORONTO, Ontario, May 24, 2007 /PRNewswire/ -- Targanta Therapeutics Corporation announced today the results from a recent study demonstrating oritavancin as a potential therapy for treating exposure to Bacillus anthracis, the bacterium which causes anthrax, an acute infectious disease. Oritavancin, a novel semi- synthetic lipoglycopeptide antibiotic for the treatment of serious gram- positive infections, is Targanta's lead product currently in post-Phase 3 clinical development. This research was conducted and presented in partnership with the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) at the American Society for Microbiology (ASM) 107th Annual General Meeting in Toronto, Ontario from May 21-25, 2007.
"We are encouraged by the research demonstrating that oritavancin may represent a potential treatment for anthrax exposure," said Thomas Parr, Ph.D., Chief Scientific Officer, Targanta Therapeutics. "This research eventually could lead to better protection for both military personnel and citizens against an anthrax attack."
Study Methods and Results:
Efficacy of Oritavancin in a Murine Model of Bacillus anthracis Spore Inhalation Anthrax
Using an aerosol-anthrax mouse model, researchers investigated oritavancin (ORI) as potential therapy for inhalational anthrax (post-exposure). In the model, mice were exposed to spores of the Ames strain of B. anthracis at seventy five times the lethal dose necessary to kill 50% of untreated mice (75 x LD50). The control group received either saline or 30 mg/kg of ciprofloxacin (CIP) intraperitoneally (within the abdominal cavity) every 12 hours for 14 days. ORI doses ranged from 0.1 to 30 mg/kg intraperitoneally every 48 hours for 14 days. Alternatively, ORI was administered intravenously from 5 to 50 mg/kg as a single intravenous dose. All treatments began 24 hours after exposure to B. anthracis spores. Survival rates at 30 days post- exposure were as follows: 90 percent survival with CIP and 100 percent survival with ORI treatment at doses equal to or greater than 3 mg/kg intraperitoneally (multiple dose) or 50 mg/kg intravenously (single dose).
A follow-up experiment showed that ORI or CIP provided significant survival rates even when the start of treatment was delayed to either 36 or 48 hours post-exposure to spores (i.e., until symptoms had begun to appear). In this experiment, ORI was administered at 10 mg/kg once every 2 days while CIP was administered at 30 mg/kg twice daily. Treatments were provided intraperitoneally for 14 days and survivorship was measured at 30 days.
In addition, a single 50 mg/kg intravenous dose of ORI administered 24 hours prior to anthrax exposure provided a 100 percent survival rate at 30 days.
Researchers at USAMRIID and Targanta concluded that their results provide impetus for investigation of whether ORI could serve as an effective therapy for anthrax exposure, requiring fewer doses compared to CIP, or perhaps even as a potential prophylactic agent.
B. anthracis, a bacterium that forms spores and causes anthrax, has been recognized for more than 60 years as a potential biological warfare agent. Such was the case in 2001, when B. anthracis spores were distributed through the U.S. Postal Service, causing 22 cases of anthrax, including five deaths. If treated promptly B. anthracis usually responds effectively to several antibiotics including penicillin, doxycycline and fluoroquinolones (including ciprofloxacin). Though ciprofloxacin is the current standard of treatment for exposure, anthrax has the possibility of being engineered to be multi-drug resistant, which would complicate treatment. The World Health Organization estimates that 50 kg of B. anthracis spores effectively released in a population of 500,000 people would result in 95,000 deaths and 125,000 hospitalizations.
Oritavancin, Targanta's lead product candidate, is a semi-synthetic lipoglycopeptide antibiotic with rapid in vitro bactericidal activity against a broad spectrum of serious gram-positive pathogens, including multi-resistant strains. Oritavancin's multiple targets and mechanisms of action work against the development of resistant strains, which is important when treating serious gram-positive infections. To date, over 1500 individuals have received oritavancin in clinical trials, including two large multi-national Phase 3 studies in complicated skin and skin structure infections (cSSSI) performed by former developers Eli Lilly and Company and InterMune, Inc. Targanta expects to file a New Drug Application (NDA) for oritavancin for the treatment of cSSSI with the U.S. Food and Drug Administration in the first quarter of 2008.
About Targanta Therapeutics Corporation
Targanta Therapeutics Corporation is a privately held biopharmaceutical company developing and commercializing innovative antibiotics to treat serious infections (either treated or acquired) in the hospital and other institutional settings. Its pipeline includes a number of antibacterial agents in various stages of development. The company has operations in Cambridge, MA, Indianapolis, IN, Montreal, Quebec, and Toronto, Ontario, Canada. For further information about Targanta, visit the company website, http://www.targanta.com.
About U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID)
USAMRIID, located at Fort Detrick, Maryland, is the lead medical research laboratory for the U.S. Biological Defense Research Program, and plays a key role in national defense and in infectious disease research. The Institute's mission is to conduct basic and applied research on biological threats resulting in medical solutions (such as vaccines, drugs and d iagnostics) to protect the warfighter. USAMRIID is a subordinate laboratory of the U.S. Army Medical Research and Materiel Command.
The information contained in this press release does not necessarily reflect the position or the policy of the Government and no official endorsement should be inferred.
All forward-looking statements and other information included in this press release are based on information available to Targanta as of the date hereof, and Targanta assumes no obligation to update any such forward-looking statements or information. Targanta's actual results could differ materially from those described in Targanta's forward-looking statements.
CONTACT: Gayle Crick Fischer, R.Ph. of Targanta Therapeutics,+1-317-502-2467; or Annie Moore of Spectrum Science Communications,+1-202-955-6222, for Targanta Therapeutics Corporation
Web site: http://www.targanta.com/
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