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 and convenience, as well as enhanced characterization and lot-to-lot consistency. PharmAthene's portfolio includes both second and third generation rPA anthrax vaccine candidates, which incorporate significant product development and technological advancements and are designed to meet these requirements. The Company's second generation rPA anthrax vaccine, SparVax(TM), is currently under consideration for a major advanced development and procurement contract through the Biomedical Advanced Research and Development Agency.
The goal of PharmAthene's third generation (3G) 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.
In a poster entitled, "Faster Time to Immunity and Enhanced Immune Response to Optimized rPA Vaccine," Allan Watkinson, R&D Director & Principal Investigator, PharmAthene UK, presented results from a mouse model in which PharmAthene and its collaborators investigated incorporating an additional immunostimulant adjuvant into a prototype 3G product formulation.
In the study, female mice were immunized in four treatment groups of 30 and blood samples were taken on days 14, 21 and 28. When immunization of mice with the lyophilized formulation of rPA was supplemented with the immunostimulant adjuvant, a significantly enhanced (p<0.005) anti-PA titre was induced, compared with the equivalent formulation lacking this adjuvant. Results showed that animals immunized with these formulations, whether supplemented with the adjuvant or not, were fully protected against challenge with 10(3 )median lethal doses of B. anthracis at day 21.
These preliminary data suggest that PharmAthene's 3G product prototype may be able to provide both faster time to immunity and significantly enhanced immunogenicity, indicating that the optimized formulation may be able to reduce the requirement for multiple vaccine doses, and simplify the immunization regimen for anthrax vaccines in the future.
Funding for this study was provided under a Challenge grant from the National Institutes of Health. The data from this study are intended to inform ongoing efforts in PharmAthene's 3G rPA program. In September 2008, PharmAthene was awarded a development contract from the National Institute of Allergy and Infectious Diseases (NIAID) of up to $83.9 million for the 3G rPA vaccine program, provided the government exercises all contract options at its sole discretion.
Source: pharmathene