Data Show Valortim(R) Anthrax Anti-Toxin May Augment Immune System's Ability to Destroy Anthrax Bacteria

ANNAPOLIS, Md., Feb. 24 /PRNewswire-FirstCall/ -- PharmAthene, Inc. (NYSE Amex: PIP), a biodefense company developing medical countermeasures against biological and chemical threats, announced today that new data from the Company's Valortim® anthrax anti-toxin program were presented at the 8th Annual ASM Biodefense and Emerging Diseases Research Meeting, held in Baltimore, Maryland, February 21-24, 2010.

The data were presented by Dr. Alan S. Cross, Professor of Medicine and Dr. Subhendu Basu, Assistant Professor, University of Maryland School of Medicine, in a poster presentation entitled Human Adaptive Immune Response to Bacillus Anthracis.  

Valortim® is a fully human anti-toxin monoclonal antibody being developed for the prevention and treatment of inhalational anthrax.  Preclinical studies suggest that Valortim® has the potential to provide protection against anthrax infection when administered prophylactically (prior to the emergence of symptoms of anthrax infection) and also may increase survival when administered therapeutically (once symptoms become evident).

Previous data presented by Drs. Cross and Basu have shown that in addition to inhibiting anthrax toxin, Valortim® appears to augment the immune system's ability to kill anthrax bacilli by enhancing the human dendritic cell response to a challenge with anthrax spores.  These new data expand upon these observations by showing that Valortim® also enhances the human T cell response to B. anthracis. In addition to Valortim's established toxin-neutralizing function, which has been previously described, these studies indicate that it may also assist in enhancing the adaptive immune response to anthrax, which may lead to a reduction and clearance of the bacteria in the host organism.

Dr. Cross remarked, "Our latest research using human immune cells provides additional evidence of the role Valortim® may play in enhancing the elimination of B. anthracis to potentially minimize the severity of infection.  We hypothesize that Valortim® may protect against lethal anthrax infection by its toxin neutralization activity that allows the development of a potent adaptive immune response that facilitates the elimination of harmful bacteria in a host organism."

David P. Wright, President and Chief Executive Officer of PharmAthene, commented, "Drs. Cross and Basu continue to make excellent progress demonstrating how Valortim® may interact with the immune system to potentially minimize the extent and severity of infection with bacillus anthracis.  These data, combined with the accumulating non-clinical efficacy results in animal models, continue to show how Valortim® may have important differentiating benefits, which, if confirmed, may make it a strong choice for procurement consideration in the Strategic National Stockpile."  

The work reported by Drs. Cross and Basu is supported by the Maryland Industrial Partnerships Program (MIPS). The MIPS program was developed to accelerate the commercialization of technology in Maryland by jointly funding collaborative R&D projects between companies and University System of Maryland faculty.

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 toxin complex produced by the bacterium.  Preclinical studies suggest that Valortim® has the potential to provide significant protection against anthrax infection when administered prophylactically post-exposure (i.e., prior to the emergence of symptoms of anthrax infection) and also may increase survival when administered therapeutically (i.e., once symptoms become evident).

Anti-toxins such as Valortim® are a key element in combating and treating anthrax infection, in addition to vaccines and antibiotics.  The Department of Health and Human Services has issued a requirement for up to 200,000 anthrax anti-toxin treatments to be included in the Strategic National Stockpile and PharmAthene believes that Valortim® is well positioned to address this need.

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 disease vary depending on how the disease is contracted, but 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:

• SparVax™ - a second generation recombinant protective antigen (rPA) anthrax vaccine
• Third generation 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

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 risks 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, 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 Form 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, significant additional 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.

SOURCE PharmAthene, Inc.