FDA approves Avelox for plague

The FDA today announced its approval of moxifloxacin for the prevention and treatment of pneumonic and septicemic plague in adult patients, according to a press release.

“Today’s approval provides an additional therapy for the treatment of plague,” Edward Cox, MD, MPH, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research, said in the press release.

According to the FDA, there are between 1,000 and 2,000 cases of plague globally each year. The three most common forms of the disease are bubonic, pneumonic and septicemic. Plague can spread to humans through bites with infected fleas, laboratory exposure or contact with infected animals or other humans.

Edward Cox

Health officials recently reported an outbreak of pneumonic plague that was traced from an infected dog to its owner and as many as three other humans in Colorado. It was the largest outbreak of plague in the U.S. since 1924, they said.

The FDA considers the bacteria that causes plague, Yersinia pestis, a potential bioterrorism threat.

The agency’s approval of Avelox (moxifloxacin, Bayer HealthCare Pharmaceuticals) was based on an efficacy study in African green monkeys that were infected with Y. pestis in the laboratory. The animals received either a 10-day regimen of moxifloxacin or placebo at least 4 hours after the onset of fever following exposure to the bacteria. All monkeys treated with the study drug survived, while none of the control animals survived.

Under the FDA’s Animal Efficacy Rule, a treatment can be approved based on findings from animal model studies in cases where it is not feasible or ethical to conduct trials in humans. The rule was invoked because the rarity of plague made it impossible to conduct an adequate efficacy trial in humans, the FDA wrote in the release.

Common adverse events associated with moxifloxacin include nausea, diarrhea, headache and dizziness, according to the FDA. The drug’s boxed warning includes information on an increased risk for tendinitis and tendon rupture, as well as worsening muscle weakness in patients with the neuromuscular disorder myasthenia gravis. Allergic reactions, liver damage, blood abnormalities, effects on the nervous system and abnormal heart rhythm have also been associated with moxifloxacin.

“However, given that plague is a very serious and often deadly condition, the benefit of [moxifloxacin] for treating plague outweighs these potential risks,” the agency wrote in the release.