ANNAPOLIS, Md., March 31 /PRNewswire-FirstCall/ --PharmAthene, Inc. , a biodefense company developing medical countermeasures against biological and chemical threats, announced today that new mechanism of action data for Valortim(R) were presented at the Keystone Symposia on Molecular and Cellular Biology Conference on Dendritic Cells, March 29-April 3, 2009 in Banff, Alberta.
The data were presented by Dr. Alan S. Cross, Professor of Medicine and Dr. Subhendu Basu, Research Associate, University of Maryland School of Medicine, in a poster presentation on March 30th entitled MAb-Enhanced, Human Dendritic Cell-Mediated Adaptive Immune Response to B. Anthracis. Valortim(R) is a fully human anti-toxin monoclonal antibody being developed in conjunction with Medarex, Inc. for the prevention and treatment of inhalational anthrax.
Previous mechanism of action data have shown that in addition to inhibiting anthrax toxin, Valortim(R) augments the immune system's ability to kill anthrax bacilli. In an in vitro mouse macrophage model, Valortim(R) enhanced the killing of B. anthracis (anthrax) by macrophages in a time and dose-dependent manner.
The new data presented by Drs. Cross and Basu build on this initial information in the mouse model by demonstrating that Valortim(R) can enhance the killing of anthrax by human dendritic cells.
Dr. Cross remarked, "These latest studies using human immune cells provide additional evidence of the role of Valortim(R) in enhancing the killing of B. anthracis. We hypothesize that Valortim(R) may protect against lethal anthrax infection by its toxin neutralization activity that allows the development of a potent human dendritic cell-mediated adaptive response that rids the host of viable bacteria."
Dr. Cross continued, "As is the case with mouse macrophages, our in vitro data suggest that human dendritic cells also kill germinating anthrax bacteria. Importantly, we find that the addition of Valortim(R) (1) enhances the ability of human dendritic cells to kill B. anthracis, (2) increases the upregulation of costimulatory immune molecules on human dendritic cells (CD40 and CD83), and (3) allows for an augmented cytokine response, particularly the pro-inflammatory cytokine IL-23 that is known to stimulate memory T cells and the production of IFN-gamma . Additional work is ongoing to better characterize how Valortim(R) enhances the immune response to B. anthracis infection."
David P. Wright, President and Chief Executive Officer of PharmAthene, commented, "We are delighted to continue our collaboration with Drs. Cross and Basu to better characterize these intriguing results. Valortim(R) has demonstrated efficacy in non-clinical studies as well as favorable safety data collected from our Phase I clinical study. We believe that Valortim(R) may have important competitive advantages, including a novel mechanism of action, which, if demonstrated, would 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(R)
Valortim(R) 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(R) 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).
As previously presented, Valortim(R) has been administered intravenously and intramuscularly to healthy human volunteers in a completed Phase 1 study, was well tolerated at doses as high as 20 mg/kg (IV), and was not immunogenic. Pharmacokinetic analysis suggested that doses as low as 1 mg/kg resulted in circulating levels of antibody after a month, with a similar potency for neutralizing anthrax toxin in vitro as was seen with serum obtained from subjects who had been vaccinated with anthrax vaccine.
Anti-toxins such as Valortim(R) 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(R) 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:
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, significant additional non-clinical animal studies, human clinical trials, and manufacturing development work remain to be completed for Valortim(R). At this point there can be no assurance that Valortim(R) 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.
CONTACT: Stacey Jurchison of PharmAthene, Inc., +1-410-269-2610,
Stacey.Jurchison@PharmAthene.com
Web site: http://www.pharmathene.com/
