The FDA approved Cangene’s botulism antitoxin product to treat patients showing signs of botulism following documented or suspected exposure to botulinum neurotoxin. The agency noted that the antitoxin, known as BAT, is the first for use in neutralising all seven known botulinum nerve toxin serotypes A, B, C, D, E, F and G.

“This product approval meets an urgent unmet medical need for the treatment of sporadic cases of life-threatening botulism and provides a medical countermeasure should botulinum nerve toxins be used in a terrorism event,” commented Karen Midthun, director of the FDA’s Center for Biologics Evaluation and Research. BAT, which is derived from horse plasma, will be maintained in the strategic national stockpile and distributed through the Centers for Disease Control and Prevention (CDC), the regulator said.

According to the FDA, the effectiveness of BAT was studied in animals, and in a trial of monkeys that had been infected with botulism, 14 of 30 that received Cangene’s antitoxin survived compared with none of 30 in the placebo group. The agency suggested that the “results provided substantial evidence that the antitoxin is reasonably likely to benefit humans with botulism.” The regulator added that the clearance of BAT “is the first approval of a plasma derivative using [its] Animal Rule,” as it is not feasible or ethical to conduct efficacy studies of the antitoxin in human.

In addition, the safety of BAT was tested in 40 healthy human volunteers and also monitored in 228 patients who received the antitoxin experimentally under a botulism treatment programme administered by the CDC. The FDA noted that the most frequently observed side effects were headache, fever, chills, rash, itching and nausea.