ViroPharma Incorporated, a biopharmaceutical company, filed a supplement to its Petition for Stay of Action with the FDA regarding the bioequivalence requirements for abbreviated new drug applications (ANDAs) that seek to copy Vancocin.

The document sets forth legal arguments in support of ViroPharma's strong belief that the decision of the FDA's Office of Generic Drugs (OGD) to lower the bioequivalence standards for generic copies of Vancocin violated numerous federal statutes and FDA's own regulations with the result that the new standard cannot, as a matter of law, be used in the review or approval of applications for generic versions of Vancocin, a company release said.

In addition to this filing, ViroPharma intends to supplement the Petition for Stay of Action later this quarter with a filing containing scientific arguments that show that the OGD's new standard is unsupportable as a matter of science.

ViroPharma intends to vigorously oppose any approach that does not require rigorous scientific methods including human clinical studies, consistent with good medicine and science. The company also believes that, given the growing number of patients with severe, and possibly life-threatening, C. difficile- associated disease, the appropriate expert advisory groups must validate the scientific and medical appropriateness of the approval standards for a generic locally acting vancomycin capsule product.

C. difficile is a bacterium, which under certain circumstances, typically after antibiotic therapy, can colonize the lower gastrointestinal tract where it may produce toxins which cause inflammation of the colon and diarrhoea, and the associated complications of disease, including death. Advanced age, gastrointestinal surgery/manipulation, long length of stay in healthcare settings, a serious underlying illness and compromised immunity are conditions associated with increased risk of disease. According to the CDC, there are approximately 3,000,000 cases of antibiotic-associated diarrhoea per year, of which 15 to 25 per cent are caused by C. difficile.