Treatment for inhalational anthrax approved

FDA has approved Anthrax Immune Globulin Intravenous (Human) (Anthrasil, Emergent BioSolutions) also known as AIGIV, for treatment of inhalational anthrax in combination with appropriate antibacterial drugs.

Anthrasil is a sterile solution of purified human immune globulin G (IgG) containing polyclonal antibodies that targets the anthrax toxins of Bacillus anthracis, the bacteria that causes anthrax disease. It is prepared using plasma collected from healthy, screened donors who have been immunized with Emergent's BioThrax (Anthrax Vaccine Adsorbed) vaccine, the only FDA-licensed vaccine for the prevention of anthrax disease.

The product qualifies for 7 years of market exclusivity.

To support the nation’s preparedness against a possible anthrax attack, the U.S. Department of Health and Human Services’ Biomedical Advanced Research and Development Authority (BARDA) purchased Anthrasil under Project BioShield in 2011 as an experimental drug for the U.S. Strategic National Stockpile. Because Anthrasil was not approved, its use prior to today’s approval would have required an emergency use authorization from FDA.

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The efficacy of Anthrasil was studied in animals because it was not feasible or ethical to conduct adequately controlled efficacy studies in humans. Rabbits and monkeys were exposed to a lethal aerosolized dose of B anthracis spores, then treated with Anthrasil or a placebo, and evaluated for survival. Survival in anthrax-infected monkeys treated with Anthrasil ranged from 36% to 70% compared to 0% survival in the placebo group with a trend toward increased survival at higher doses of Anthrasil. Rabbits treated with a moderate dose of Anthrasil after infection exhibited 26% survival compared to 2% survival in the placebo group. Another 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.

Inhalational anthrax, considered to be the most deadly form of anthrax, is a rare disease that can occur after exposure to infected animals or contaminated animal products, or as a result of an intentional release of anthrax spores. It is caused by breathing in the spores of the bacterium B anthracis. Infection usually develops within a week after exposure, but it can take up to 2 months. Without treatment, only about 10% to 15% of patients with inhalation anthrax survive. However, with aggressive treatment, about 55% of patients survive.

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