Building a Better Anthrax Vaccine

vaccine1Swine flu may be causing a current panic, but eight years ago, our big concern was anthrax. In 2001, shortly after the 9/11 terrorist attacks, letters laced with anthrax were sent all over the U.S. Five people died and 17 were sickened in what the Federal Bureau of Investigation called “the worst biological attacks in U.S. history.”

Anthrax is an infectious disease caused by the bacterium Bacillus anthracis. According to the U.S. Centers for Disease Control, anthrax spores can enter the body through inhalation, a skin wound, or ingestion. Inhalation anthrax, seen in the 2001 attacks, begins with cold-like symptoms but can progress to breathing difficulties and shock. It is usually fatal; the government reports that 80 to 90 percent of people with inhalation anthrax will die if left untreated. Anthrax is generally treated with antibiotics.

An anthrax vaccine is recommended for military personnel and those who work in high-risk environments, but the current vaccine has drawbacks: It only provides temporary immunity, and about 20 percent of patients develop uncomfortable side effects such as redness and swelling at the injection site. Emergent BioDefense (formerly BioPort) of Lansing, Mich., currently has the only FDA-licensed anthrax vaccine on the market.

With bioterrorism fears just as strong today, there is a pressing need for a widely available, safe anthrax vaccine. Two announcements in the past week may bring us closer to that goal. Researchers at the Albert Einstein College of Medicine at Yeshiva University have reported the discovery of two protein fragments that could lead to the creation of a better-tolerated anthrax vaccine. And PharmAthene of Annapolis, Md., presented new data on its anthrax vaccine, Valortim, at the Bacillus – ACT 2009 conference. Valortim is a fully monoclonal antibody designed to protect against inhalation anthrax. It works by targeting a harmful antigen that attaches itself to cells and allows additional toxins in.   The most recent data showed that Valortim protected mice with impaired immune systems from developing anthrax. Earlier Phase I data, released in 2006, demonstrated that Valortim was safe and well tolerated by human patients. Valortim has received fast-track and orphan drug designations from the U.S. Food and Drug Administration.

Other companies working to treat or defend against anthrax include Vaxin, Aradigm Corporation, Human Genome Sciences, and Ligocyte Pharmaceuticals.

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