Inhalation Anthrax Treatment Approved

The FDA has approved obiltoxaximab (Anthim) injection to treat inhalational anthrax in combination with appropriate antibacterial medications.

Anthim may also be used to prevent inhalational anthrax when other therapies are not available or appropriate.

Patients could inhale anthrax through an intentional release of spores, or if they are exposed to infected animals or contaminated animal products.

The disease is caused by breathing in the spores of Bacillus anthracis, which can cause irreversible tissue injury and death. The FDA warned that anthrax spores are “resistant to destruction” and pose a bioterrorism threat since they can be spread through the air.

“As preparedness is a cornerstone of any bioterrorism response, we are pleased to see continued efforts to develop treatments for anthrax,” said Edward Cox, MD, MPH, director of the Office of Antimicrobial Products in FDA’s Center for Drug Evaluation and Research, in a press release.

The FDA’s Animal Rule, which allows the manufacturer to use efficacy findings from well-controlled animal studies, led to Anthim's approval because it would not be feasible or ethical to conduct efficacy trials in humans. In trials of Anthim, treatment and prophylaxis of inhalational anthrax were tested in animals based on whether they survived to the end of the study.

The researchers found that more animals who were treated with Anthim survived than animals treated with placebo. They also found that animals treated with both Anthim and antibacterial drugs had better survival outcomes than antibacterial therapy alone.

Elusys Therapeutics Inc’s drug was also evaluated for safety in 320 human volunteers. The most common adverse effects they experienced were headache, itching, upper respiratory tract infections, cough, nasal congestion, hives, and bruising and pain at the infusion site.

Anthim has a boxed warning about its risks for allergic reactions, including anaphylaxis.

“However, given that anthrax is a very serious and often deadly condition, the benefit of Anthim for treating anthrax is expected to outweigh this risk,” the FDA noted in a press release.