Firms vie for anthrax pacts

Annapolis, Rockville companies seeking share of millions of vaccine doses

The Department of Health and Human Services wants the new vaccine to be made with modern recombinant DNA processes, which provide a purity and enhanced effectiveness that can eliminate side effects and reduce the number of injections.

In recombinant vaccine production, bioengineers alter the genetics of benign micro-organisms to produce a desired protein - in this case a specific anthrax protein called the "recombinant protective antigen," or rPA. This is a single, pure protein found to stimulate an immune response in people without causing illness or serious side effects.

SparVax was originally developed by a British firm, Avecia Biotechnology, beginning in 1999, with $150 million in funding from the National Institutes of Health, Wright said. PharmAthene bought the company this year.

Its protective antigen is manufactured by an E. coli bacterium, Wright said. "It is a single protein, a recombinant version of the rPA. Consequently, it works with only three doses instead of six. And those three doses can be given over 60 days instead of 180 days."

Wright said his product has proven safe in phase II trials involving 700 volunteers and effective in producing the correct immune response. In trials with monkeys challenged with lethal doses of anthrax, the drug proved 100 percent effective, he said.

Emergent has its own recombinant anthrax vaccine, called rPA 102, purchased from VaxGen Inc., and improved after the Department of Health and Human Services withdrew $887 million in funding from VaxGen.

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