PharmAthene, Inc. (NYSE Amex: PIP), a biodefense company developing medical countermeasures against biological and chemical threats, announced today the presentation of new data from the Company's anthrax vaccine program showing that its lyophilized recombinant Protective Antigen (rPA) based anthrax vaccine is structurally stable and potent after 16 months at various temperatures up to and including 55 degrees C. The data were presented by Dr. Matthew Duchars, Chief Scientific Officer for PharmAthene, during an oral session at the HHS Public Health Emergency Medical Countermeasures Enterprise (PHEMCE) Stakeholders Workshop 2009 / BARDA Industry Day.
David P. Wright, President and Chief Executive Officer of PharmAthene, commented, "These new data are very encouraging as they demonstrate that PharmAthene's lyophilized rPA could be used to provide a stable cold-chain-free vaccine, enabling us to develop a formulation which could be stored and distributed at room temperature, an important attribute for deployment in the civilian Strategic National Stockpile."
Next Generation Anthrax Vaccines
Various government agencies, including the Institute of Medicine, have acknowledged the urgent need to stockpile next-generation anthrax vaccines employing modern vaccine technology, which offer the potential for improved safety, convenience and more rapid immunity, ideally with a potential to provide protective immunity in sixty days compared to six months for the currently licensed anthrax vaccine.
As a result of this Federal requirement, a Request for Proposals (RFP) was issued by the Biomedical Advanced Research and Development Authority (BARDA) for the acquisition of 25 million doses of rPA anthrax vaccine for the Strategic National Stockpile. The Company's second generation rPA anthrax vaccine, SparVax(TM), is currently under consideration for a major advanced development and procurement contract through BARDA.
PharmAthene's portfolio includes second generation and third generation rPA anthrax vaccine product candidates, which incorporate significant product development and technological advancements and are designed to meet these requirements.
The goal of PharmAthene's third generation rPA vaccine program is to develop a vaccine formulation which can induce a more rapid onset of protective immunity in fewer doses, and can be stored, transported and used without the need for a conventional cold chain -- an important advantage for civilian biodefense deployment within the Strategic National Stockpile.
Summary of the Data Presented
In an oral presentation entitled, "Development of a Highly Stable Lyophilized rPA-Based Anthrax Vaccine," Dr. Duchars presented results from a series of studies evaluating different approaches to increase the stability of an rPA anthrax vaccine product candidate. Of the techniques evaluated, lyophilization showed exceptional stability. An optimized lyophilized formulation of rPA was subsequently tested in an accelerated stability study at 5 degrees C; 25 degrees C; 40 degrees C; and 55 degrees C.
At 3 months, little evidence of rPA degradation was detected in the samples at all temperatures up to and including 55 degrees C. Using the mouse challenge assay, the lyophilized rPA vaccine was shown to have retained potency. Subsequent analysis at 16 months demonstrated that the rPA had retained both structural integrity and vaccine potency.
These preliminary data suggest that an optimized rPA formulation could be used to provide a stable cold-chain-free vaccine. Scale-up of the lyophilization process is currently underway.