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"PharmAthene continues to advance its anthrax pipeline and work collaboratively with the U.S. Government to develop novel vaccines and therapies to address this potentially serious terrorist threat, which has a lethality rate approaching 100% in untreated individuals," commented David P. Wright, President and Chief Executive Officer. "Accumulating evidence suggests that our product, Valortim®, possesses important characteristics that may make it a strong choice for procurement in the Strategic National Stockpile for civilian biodefense, including: demonstrated efficacy in animal models as both a prophylactic and therapeutic for inhalational anthrax; the potential for direct and indirect killing of Bacillus anthracis, a mechanism of action not previously described for other monoclonal antibodies; and, efficacy at low doses."
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Summary of Data Presented
In an oral presentation entitled, "Efficacy of Valortim® in the New Zealand White Rabbit Model for Inhalation Anthrax" Dr. Elizabeth Leffel, Director of Non-Clinical Sciences at PharmAthene presented the results from two separate studies where NZW rabbits were challenged with a targeted aerosolized dose of 200 times the median lethal dose of B. anthracis (Ames strain) spores and subsequently treated with either saline control or 20, 10 or 2.5 (Study 2 only) mg/kg intravenous Valortim®.
Animals in the study were carefully monitored to ensure active anthrax infection at the time treatment was initiated, as determined by evidence of either antigenemia (Protective Antigen measured in serum) or after 3 significant increases in body temperature.
In the first study, 100% (8/8) of the animals receiving 20 mg/kg of Valortim, 83% (10/12) receiving 10 mg/kg of Valortim®, and 8% receiving placebo control survived aerosol challenge. Overall, Valortim® provided protection in 90% of the animals showing signs of active anthrax infection.
In the second study, survival rates were 88% (7/8), 75% (6/8), and 75% (6/8), in the 20mg/kg, 10 mg/kg, and 2.5 mg/kg dose groups, respectively. One surviving control animal may have received 20mg/kg of Valortim®, which will be confirmed through a pharmacokinetic analysis.
When the results from both studies were combined, survival rates were: 94% at 20 mg/kg, 80% at 10 mg/kg, and 75% at 2.5 mg/kg. In these two studies, the clinical triggers used for treatment initiation were appropriate predictors of bacteremia, the traditionally accepted indicator of active anthrax infection.
"We are very excited about these new data, which showed Valortim® to be an effective treatment at very low doses in the NZW rabbit model for inhalation anthrax," said Mr. Wright. "The impressive survival rates in these studies further demonstrate the potential for Valortim® to provide treatment for individuals displaying signs or symptoms following lethal inhalation exposure to anthrax. We look forward to continuing to work collaboratively with the Government to advance the development of Valortim® and potentially fulfill a critical need in the Nation's biodefense anthrax armamentarium."
Funding for these studies was provided by the National Institutes of Health / National Institute of Allergy and Infectious Diseases (NIAID) under grant U01 AI061314-02, and by NIAID and the Biomedical Advanced Research and Development Authority (BARDA) under contract HHSN272200700033C.
About Valortim®
Valortim® is a fully human monoclonal antibody designed to protect against and treat anthrax infection, including inhalational anthrax, the most lethal form of illness in humans caused by the Bacillus anthracis bacterium. The investigational antibody is designed to target a protein component known as the anthrax Protective Antigen (PA) of the lethal and edema toxin complexes produced by the bacterium. Non-clinical studies suggest that Valortim® has the potential to provide significant protection against inhalational anthrax when administered prophylactically post-exposure (i.e., prior to the emergence of signs/symptoms of anthrax infection) and to increase survival when administered therapeutically (i.e., once signs/symptoms become evident).
Anti-toxins such as Valortim® are a key element in combating and treating anthrax infection, in addition to vaccines and antibiotics, and are an essential requirement for the Strategic National Stockpile. PharmAthene believes that Valortim® is well positioned for procurement consideration in the civilian biomedical stockpile.
About Anthrax
According to the Centers for Disease Control and Prevention, anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax most commonly occurs in hoofed mammals and can also infect humans. Symptoms of the disease vary depending on how it is contracted, but they usually occur within seven days after exposure. The serious forms of human anthrax are inhalation anthrax, cutaneous anthrax, and intestinal anthrax. Initial symptoms of inhalation anthrax infection may resemble a common cold. After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax is often fatal, even if treated by antibiotics. Currently, antibiotics are the only drugs available for therapeutic or prophylactic use for inhalation anthrax, and post-exposure prophylaxis is the only FDA-approved indication for such products. However, antibiotic therapy, while useful, is believed to be associated with a number of limitations, including: (1) lack of activity against the toxins produced by the B. anthracis bacteria, (2) need for long-term dosing to achieve full protection, complicated by side effects and non-compliance, (3) lack of efficacy when administered late in the anthrax disease cycle, and (4) lack of effectiveness against multi-drug resistant or genetically engineered strains of anthrax.
About PharmAthene, Inc.
PharmAthene was formed to meet the critical needs of the United States and its allies by developing and commercializing medical countermeasures against biological and chemical weapons. PharmAthene's lead product development programs include:
For more information about PharmAthene, please visit www.PharmAthene.com.
Statement on Cautionary Factors
Except for the historical information presented herein, matters discussed may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Statements that are not historical facts, including statements preceded by, followed by, or that include the words "potential"; "believe"; "anticipate"; "intend"; "plan"; "expect"; "estimate"; "could"; "may"; "should"; or similar statements are forward-looking statements. PharmAthene disclaims, however, any intent or obligation to update these forward-looking statements. Risks and uncertainties include risk associated with the reliability of the results of the studies relating to human safety and possible adverse effects resulting from the administration of the Company's product candidates, unexpected funding delays and/or reductions or elimination of U.S. government funding for one or more of the Company's development programs, including without limitation our bid related to SparVax(TM) under the DHHS Request for Proposals for an Anthrax Recombinant Protective Antigen (rPA) Vaccine for the Strategic National Stockpile, the award of government contracts to our competitors, unforeseen safety issues, challenges related to the development, scale-up, and/or process validation of manufacturing processes for our product candidates, unexpected determinations that these product candidates prove not to be effective and/or capable of being marketed as products, as well as risks detailed from time to time in PharmAthene's Forms 10-K and 10-Q under the caption "Risk Factors" and in its other reports filed with the U.S. Securities and Exchange Commission (the "SEC"). In particular, there can be no assurance that the Company will be awarded a contract or funding under the solicitation under BAA-BARDA-09-34. Further, significant additional research work, non-clinical animal studies, human clinical trials, and manufacturing development work remain to be completed for Valortim®. At this point there can be no assurance that Valortim® will be shown to be safe and effective and approved by regulatory authorities for use in humans.
Copies of PharmAthene's public disclosure filings are available from its investor relations department and our website under the investor relations tab at www.pharmathene.com.
-- SparVax(TM) -- a second generation recombinant protective antigen (rPA) anthrax vaccine -- Valortim® -- a fully human monoclonal antibody for the prevention and treatment of anthrax infection -- Protexia® -- a novel bioscavenger for the prevention and treatment of morbidity and mortality associated with exposure to chemical nerve agents -- RypVax(TM) -- a recombinant dual antigen vaccine for plague -- A third generation rPA anthrax vaccine.
SOURCE PharmAthene, Inc.
