Judge won't toss suit over Wellbutrin generics

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FDA approval doesn't shield generic drugmakers from lawsuits, either, a federal judge ruled in refusing to dismiss a case against Teva Pharmaceutical Industries (NASDAQ: TEVA) and Impax Laboratories (NASDAQ: IPXL) over their versions of the branded drug Wellbutrin XL.

The suit claims that both Teva and Impax knew that the release rate of the active ingredient was faster in their drugs than with the branded version, but did not warn the public about those differences. The companies had sought to have the suit dismissed because the FDA had declared their generic versions "bioequivalent" to the branded med.

It's all about drug delivery in this situation: According to court papers, GlaxoSmithKline's (NYSE: GSK) Wellbutrin XL used membrane technology to control release of the drug's active ingredient over time. However, the membrane technology was patented, so generics makers had to come up with their own delivery mechanisms. A couple of generics makers developed their own membrane technologies, but Impax and Teva used a different method. The membrane versions achieved peak concentrations in five hours, but the Impax and Teva versions delivered the ingredient faster, with peak concentrations coming in just two hours, the suit says.

The judge's recent ruling isn't on the facts of the case; it's about responsibility. U.S. District Judge Berle Schiller, citing the Supreme Court's recent decision in the big pre-emption case, Wyeth v. Levine, said that the FDA's approval isn't a free pass for generics makers. Yes, the Hatch-Waxman Act allows copycat drugs to come on the market with that "bioequivalent" certification, but the law "does not allow generic drugmakers to wash their hands of any responsibility for monitoring the safety and efficacy of their drugs once sold," the judge wrote. And so the case goes forward.

- read the story from Legal Intelligencer

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