FDAnews Drug Daily Bulletin


March 17, 2006

The FDA has granted orphan drug status to Medarex and PharmAthene's new drug application for Valortim, an experimental treatment for anthrax infection, the firms recently announced.

Orphan drug status is granted to drugs that treat rare diseases and conditions, specifically those expected to affect fewer than 200,000 people in the U.S. Orphan drugs receive seven years of market exclusivity. The FDA granted fast-track status to the drug in January.

Valortim may be the superior choice for procurement in the Strategic National Stockpile under Project BioShield, said the head of PharmAthene recently.

The drug's action mechanism appears to work under the same mechanism as the natural protective response to anthrax vaccine, noted David Wright, president and CEO of PharmAthene. Valortim also has the potential to provide immediate immunity compared to vaccines, which may take months to confer immunity, he added.

"Despite aggressive antibiotic therapy and supportive care, the anthrax attacks of 2001 resulted in a mortality rate of nearly 50 percent, illustrating the urgent need for more effective anthrax therapeutics," said Wright. "Our receipt of orphan drug designation for Valortim -- and, earlier this year, fast-track designation -- should facilitate a more streamlined development process through more frequent dialogue with the FDA."

Valortim is an investigational, fully human antibody that targets the Bacillus anthracis protective antigen. Animal studies have demonstrated efficacy in both pre- and postexposure prophylaxis and treatment for anthrax infection; potentially enabling therapeutic intervention after the appearance of disease symptoms, when antibiotic therapy is progressively less effective, the companies said.