Cangene Wins U.S. FDA Approval for Antidote to Botulism

Cangene Corp. won U.S. approval for its antidote for the botulism toxin considered a bioterrorism threat.

The Food and Drug Administration cleared the antitoxin, the agency said today in a statement. Botulism causes paralysis that can lead to death once the airway and breathing muscles stop moving.

Cangene, based in Winnipeg, Canada, currently supplies the antitoxin to the U.S. under an emergency-use exemption. The federal government awarded Cangene a contract in 2006 that is now valued at $476 million for late-stage development of the antitoxin and 200,000 doses, according to the arm of the Department of Health and Human Services responsible for preparing vaccines and drugs for national emergencies.

“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,” Karen Midthun, director of the FDA’s Center for Biologics Evaluation and Research, said in the statement.

The botulism toxin can be used as a bioterror weapon if deliberately released as an aerosol or in food or drink. Naturally occurring cases can occur in food or drink as well, often in inadequately canned foods, and contaminated wounds, according to the Center for Biosecurity of the University of Pittsburgh Medical Center in Baltimore, Maryland.

Yearly Cases

An average of 110 cases of botulism are reported each year, according to the Occupational Safety and Health Administration.

In a study on monkeys, 14 of 30 that received the Cangene antitoxin survived compared with none of 30 in a placebo group that had been infected with botulism.

“These results provided substantial evidence that the antitoxin is reasonably likely to benefit humans with botulism,” the FDA said in the statement. “Under the FDA’s Animal Rule, the agency may approve a biological product when the results of well-controlled animal studies demonstrate that the product is reasonably likely to be effective, in addition to establishing safety in humans. This is the first approval of a plasma derivative using the Animal Rule.”

The drug’s safety also was tested in 40 human volunteers and monitored in 228 patients who received it experimentally under a program administered by the U.S. Centers for Disease Control and Prevention, the FDA said. The most common side effects were headache, fever, chills, rash, itching and nausea.

The antidote will be maintained in the strategic national stockpile and distributed through the Atlanta-based CDC’s drug service, the FDA said.

Cangene reported $111 million in revenue for the fiscal year ended in July. The company’s shares declined 2.5 percent to C$2.75 at the close of trading today in Toronto before the announcement and have gained 49 percent in the past 12 months.