Currently, the only licensed vaccine against anthrax in the United States is AVA BioThrax®. Although efficacious, AVA BioThrax® suffers from several limitations. AVA BioThrax® requires six injectable doses over 18 months to stimulate protective immunity, requires a cold chain for storage, and in many cases has been associated with adverse effects.
FDA inventors developed a vaccine candidate against Anthraxcomprising a modified plasmid encoding the B. anthracis protective antigen (PA) gene with optimal expression and stability, linked to an inducible promoter for maximal expression in the host, and fused to the secretion signal of the Escherichia coli alpha-hemolysin protein (HlyA) on a low-copy-number plasmid. This plasmid was introduced into the licensed typhoid vaccine strain, Salmonella entericaserovar Typhi strain Ty21a, and was found to be genetically stable. Immunization of mice with three vaccine doses elicited a strong PA-specific serum immunoglobulin G response with a geometric mean titer of 30,000 (range, 5,800 to 157,000) and lethal-toxin-neutralizing titers greater than 16,000. Vaccinated mice demonstrated 100% protection against a lethal intranasal challenge with aerosolized spores of B. anthracis 7702. The ultimate goal is a temperature-stable, safe, oral human vaccine candidate against anthrax infection that can be self-administered in a few doses over a short period of time.
|Potential Commercial Applications||Competitive Advantages|
Development Stage: in vitro
Inventors: Dennis Kopecko, Manuel Osorio, Chandrakan Giri, Milan Blake, Siba Bhattacharyya
Kopecko, D.J. et al., Anthrax protective antigen delivered by Salmonella enterica serovar Typhi Ty21a protects mice from a lethal anthrax spore challenge. Infect Immun. 2009 Apr;77(4):1475-82, PMID: 19179420
United States Patent No.7,758,855 issued 2010-07-20, United States Patent No. 8,247,225 issued 2012-08-21, United States Patent No. 8,709,813 issued 2014-04-29, International patentsalso issued
Product Area: Vaccine candidate, biodefense, biodefense countermeasure
FDA Reference No: E-2003-032
Ken Millburne, J.D.
FDA Technology Transfer Program