ViroPharma Loses Long Fight With FDA Over Antibiotic

ViroPharma Loses Long Fight With FDA Over Antibiotic

April 11th, 2012 // 12:40 pm @

Source: Pharmalot

For the past several years, ViroPharma has battled the FDA over the standards that the agency can employ to permit generic versions of it Vancocin antibiotic, which is used to treat gastrointestinal infections. The latest – but maybe not the final – chapter ended yesterday when the FDA denied a ViroPharma citizen petition, clearing the way for generic launches (read the citizen petition here). And generic rivals did, indeed, begin shipping their meds.

Not surprisingly, ViroPharm stock is taking a beating – shares fell 19 percent at one point. Until today, Vancocin was the only approved drug to treat clostridium difficile-associated pseudomembranous colitis, or CDI, which is a common and potentially life-threatening hospital-acquired infection. Up to 500,000 cases of CDI infection are reported each year at hospitals and clinics in the US. Meanwhile, the FDA also said a supplemental approval for Vancocin wouldn’t qualify for three additional years of exclusivity.

At issue is the method the FDA used to determine bioequivalency. Five years ago, the agency decided that in vivo, or human studies, would no longer be required. Instead, an in vitro dissolution test would suffice. ViroPharma, in response, filed a lawsuit and citizen petition. Meanwhile, the drugmaker lacked any patent or data exclusivity protection, but its legal maneuvering succeeded in delaying FDA approval of generic rivals.

Of course, such tactics are not new – brand-name drugmakers regularly file citizen petitions to thwart generic competition. ViroPharma, however, may have taken the practice to new heights. The drugmaker supplemented its petition no less than 18 times over the years and the FDA needed 87 single-spaced pages, replete with numerous footnotes on most every page, to explain its rejection.

“ViroPharma’s petition, and its numerous supplements, stands alone as the poster child of citizen petition abuse,” wrote the lawyers for Akorn, one of the two generic drugmakers that urged the agency to reject the ViroPharma argument (here is the Akorn brief that was filed in the federal court lawsuit brought by ViroPharma against the FDA). The other drugmaker that was angling to sell a generic version of Vancocin was Watson Pharmaceuticals, which began shipments today.

There was more bad news for ViroPharma, though. The FDA ruled ViroPharma’s supplemental new drug application for Vancocin, approved Dec. 14, 2011, would not qualify for three additional years of exclusivity because it did not include a significant new use or indication for the product. And the US Federal Trade Commission is investigating whether the drugmaker engaged in unfair competition.

Just the same, the drugmaker succeeded in delaying generic competition for five years. Meanwhile, the register was ringing. Last year, Vancocin sales were nearly $289 million, or 53 percent of revenue. In 2010, Vancocin sales were almost $260 million, or 59 percent of revenue (see here). The stock is down, but the legal maneuvering offered some rewards. And there will be more. In a conference call with analysts, ViroPharma ceo Vincent Milano says a lawsuit will be filed seeking an injunction to prevent generic rivals from shipping their versions.

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