Anthrax Treatment Approved

The FDA has approved an experimental therapeutic to treat deadly inhalation anthrax. The drug is stockpiled in guarded facilities in preparation for a possible anthrax attack, but the approval means it can be used without an FDA emergency use declaration.

The US Food and Drug Administration (FDA) has approved the use intravenous use of human anthrax immune globulin (Anthrasil/Cangene Corp.) to treat patients with inhalational anthrax.

Approved as an orphan drug, tt is recommended for use in combination with appropriate antibacterial drugs. The drug was originally developed to be used in the event of a possible anthrax attack, but the approval means it will be available for other uses. It is a made from polyclonal antibodies in purified human immune globulin using plasma from donors immunized with Emergent BioSolution's ’BioThrax anthrax vaccine.

Supplies of Anthrasil are stored in the US Strategic National Stockpile. In 2011 a supply was was purchased by the US Department of Health and Human Services’ Biomedical Advanced Research and Development Authority (BARDA) as an experimental drug.

Outside of a terrorist attack, the disease is rare. It can occur after exposure to infected animals or contaminated animal products.

Breathing the spores of Bacillus anthracis causes the body to produce toxins that irreversibly damage tissues and results in death.

Due to ethical considerations, the efficacy of Anthrasil was studied only in animals. Those tests showed it is not 100% effective, the FDA said.

Survival in anthrax-infected monkeys treated with Anthrasil ranged from 36% to 70% compared to no survival in the placebo group. Survival in rabbits treated with a moderate dose of Anthrasil was 26% survival compared to 2% in the placebo group. A second study in rabbits showed that a combination of Anthrasil and antibiotics resulted in 71% survival compared to 25% survival in animals treated with antibiotics alone.

The safety of the product was tested in 74 healthy human volunteers. The most commonly observed side effects were headache, back pain, nausea and infusion site pain and swelling.

The product was developed by the Canadian company Cangene Corporation. It was acquired by Emergent BioSolutions last year.

In a press release, Emergent BioSolutions said under its agreement with BARDA, the approval triggers a $7 million payment and gives the company 7-year exclusivity on the product.

Anthrasil was developed as part of a $160 million contract with BARDA, the company said. Emergent is based in Gaithersburg, MD.