(CN) - A federal judge held that a valid patent protects flu-weakening drug Tamiflu, preventing Natco Pharma from manufacturing a generic version of the drug.
Gilead Sciences owns the patent for Oseltamivir, marketed as Tamiflu, a drug stockpiled by numerous governments in preparation for a flu outbreak.
Tamiflu has come under recent criticism because the drug's maker refuses to release information from eight of 10 Tamiflu clinical trials, and some researchers have questioned the drug's effectiveness.
In 2011, Natco Pharma applied with the FDA to market a generic version of Tamiflu, but Gilead sued in federal court alleging that Natco's application violated its patent.
Natco claimed, in its defense, that Gilead's patent is invalid because it covers the same subject matter as an earlier-dated patent. Double-patenting renders a patent invalid, to preclude inventors from improperly extending the statutory limit of patent protection.
However, U.S. District Judge Susan Wigenton disagreed, ruling that "Natco's argument is ineffective.""The lifespan of Gilead's patents seem to be a result of changes in patent law, and not any gamesmanship from Gilead. Since the issuance of the '483 patent is not the result of any strategic abuse of the patent system by Gilead, the '375 patent cannot serve as a reference patent to invalidate the '483 patent because of obviousness-type double-patenting," Wigenton said, granting Gilead's motion for summary judgment.
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