REGULATORY PATHWAY FOR BIODEFENSE VACCINES

Typically, the U.S. Food and Drug Administration (FDA) requires extensive animal testing followed by three phases of human clinical studies before considering a drug or vaccine for approval and ultimate sale to the public. In the case of biodefense however, it is not be ethically possible to study the efficacy of certain vaccines in humans as such study would require volunteers to be administered lethal doses of the pathogen, be it anthrax, botulinum toxin, smallpox or ricin. In lieu of such testing, the FDA has instituted the “Animal Rule.”

Under the Animal Rule, the FDA will accept data from studies in animals to provide evidence of efficacy in humans. To be considered under the Animal Rule, the action of the toxin on the body and the action of the vaccine to prevent or ameliorate the effects of the toxin must be “reasonably well-understood.” In addition, vaccine producers must show that the vaccine is effective in more than one species of animal whose reactions are expected to be the same as that of humans. The regulation also requires post-marketing studies, when such studies are feasible.

Limited human testing is still required. The vaccine must be able to produce an immune response in healthy human volunteers and be shown in those volunteers to be safe.