FDA Approves Anthrax Treatment

The FDA announced today that it has approved a new indication for BioThrax (Anthrax Vaccine Adsorbed) to prevent disease following suspected or confirmed exposure to Bacillus anthracis, the bacterium that causes anthrax disease.

According to the FDA announcement, “the vaccine’s new use is approved for people 18 through 65 years of age in conjunction with recommended antibiotic treatment. BioThrax was initially approved by the FDA in 1970 for the prevention of anthrax disease in persons at high risk of exposure..”

BioThrax is the first vaccine to be approved based on the FDA’s “Animal Rule,” which “allows animal efficacy data to be used as a basis for approval when human efficacy studies are not ethical or feasible.”

Researchers assessed levels of protective antibodies in the blood of rabbits and monkeys to predict efficacy to "predict efficacy in humans based on an assessment of the extent of antibody response achieved in human study participants.”

Infected rabbits treated with post-exposure antibiotic and BioThrax had a survival rate of 70 to 100 percent, depending on the vaccine dose administered. Rabbits treated only with antibiotics had 23-44 percent survival rates.

The FDA noted that the safety profile for BioThrax is “well-established, with the majority of localized adverse events reported as tenderness, pain, swelling, and redness at the injection site, as well as limited movement of the injected arm. The most common systemic adverse reactions were muscle aches, headache, and fatigue.”