The company’s name represents its goal to protect the nation’s citizens and troops from chemical and biological warfare, just as the goddess Athena was believed to protect ancient soldiers marching into battle. PharmAthene’s pipeline reflects this mission.
In 2001, anthrax spores sent through the mail infected 11 victims, and five of them died, even after aggressive antibiotic therapy. This bioterrorism incident underscored the need for improved vaccines and antitoxins to protect the nation.
PharmAthene’s SparVax™ is a second-generation recombinant vaccine that will require just three doses given a few weeks apart, says Richman. Completed Phase I and II trials involving about 770 people have shown that SparVax is well tolerated and induces an immune response in humans, he adds. SparVax also protects rabbits and monkeys against a lethal aerosol dose of anthrax spores.
“SparVax is intended as a vaccine to protect people before exposure to anthrax or as a treatment combined with antibiotics after exposure,” notes Wright. He predicts that SparVax will begin to reach government stockpiles within the next several years.
PharmAthene is also working on a third-generation recombinant protective antigen anthrax vaccine. Although the third-generation vaccine will be as effective as SparVax, it will achieve immunity with fewer injections, and it will remain stable for three years at room temperature. This will allow the anthrax vaccine to be stored, transported, and used without the need for refrigeration.
Another anthrax-based product is Valortim®, a fully human monoclonal antibody antitoxin designed to protect cells from damage by anthrax toxins. In preclinical studies, Valortim both protects against infection, and when given some time after anthrax exposure, it induces recovery and survival in animals exposed to 100 times the lethal dose of inhalation anthrax spores, explains Wright. “Valortim will be administered to people with a severe anthrax infection, which occurs as the lethal toxin rapidly multiplies in the body,” he adds. The FDA has granted Valortim Fast Track and Orphan Drug status.
Protexia® is a recombinant version of human butyrylcholinesterase (BChE) found naturally in minute quantities in blood. BChE acts as a natural bioscavenger to absorb and degrade organophosphate poisons that cause neurological damage. Protexia is being developed as a pre- and post-exposure therapy for military or civilian victims of nerve gas attack such as sarin, soman, or tabun. Phase I studies of Protexia should conclude later this year. The next phase will be taking Protexia through the FDA approval process.
RypVax™, a recombinant plague vaccine, contains two antigens to protect against bubonic plague and inhalation plague. The vaccine is intended for soldiers before deployment. Three Phase I trials show that RypVax is safe and well tolerated, and the vaccine fully protects animals in preclinical studies against a lethal aerosol challenge.