PharmAthene receives clinical hold on anthrax vaccine program

PharmAthene, Inc., said on Monday that a clinical hold has been placed on its SparVax rPA anthrax vaccine program by the U.S. Food and Drug Administration.

The clinical study is in Phase II, and was expected to begin by the end of the year. Researchers have not enrolled any subjects for the trial and said it has no adverse events to report. The FDA said it would send a letter with details regarding the clinical hold within 30 days.

Bacillus anthracis is a bacterium that produces three toxins when it germinates. The first toxin produced, anthrax Protective Antigen, begins the process of the bacteria attaching itself to cells of the infected person, where it enables two additional toxins, Lethal Factor and Edema Factor, to access the cells.

The standard treatment for patients infected with anthrax is antibiotics, which require early diagnosis to be effective.

PharmAthene's SparVax uses a purified protein, Protective Antigen, to stimulate the body's ability to produce a specific natural defense against anthrax.

PharmAthene is a biodefense company that develops countermeasures against biological and chemical threats. In addition to the anthrax vaccine, the company produces a medical countermeasure for nerve agents, including gases and pesticides.