The FDA has approved Levaquin (levofloxacin)(Johnson & Johnson’s) for the treatment of pneumonic plague (caused by Yersinia pestis). A member of the fluoroquinolone family of drugs, it is currently approved for treatment of numerous infections, including post-inhalation Anthrax exposure. The approval was not based on human efficacy trials, however, but was approved under the agency’s Animal Efficacy Rule, which allows efficacy findings from adequate and well-controlled animal studies to be used in cases where it is not feasible or ethical to conduct trials in humans. Animal studies were conducted with a group of 17 African green monkeys treated with Levaquin vs a placebo-treated group. Over 94% of the treated monkeys survived, whereas none of the placebo dosed animals survived. Also approved for treatment of plague are streptomycin, doxycycline, tetracycline, and other antibacterial drugs in the tetracycline group. See the FDA News Release for more information. To learn more about the Animal Efficacy Rule, click here.