Singulair patent in the clear after PTO ruling

The U.S. Patent and Trademark Office has made sure that Merck's Singulair team enjoys its weekend. The PTO reversed its tentative rejection of key claims in the company's patent for the blockbuster allergy and asthma treatment. And the patent regulator says it's done with re-examining Singulair's patent coverage.

So it looks as if the drug will stay on patent until 2012 as Merck had hoped. And that's a huge deal for the drugmaker, because with $4.5 billion in 2008 sales--$3.4 billion over the first nine months of this year--Singulair is Merck's best-selling medication.

Merck has been fighting off Singular patent challenges on a couple of fronts. Teva Pharmaceutical Industries had sued the company to challenge the drug's patent, but a federal court ruled in favor of Merck back in August--not only upholding the company's patent but issuing an injunction to stop approval of Teva's generic version until the patent expires in August 2012.

Separately, Article One Partners, an online patent-research service, said it had uncovered new information raising questions about the validity of the Singulair patent, according to Dow Jones. The PTO tentatively rejected key claims of the patent but withdrew that decision because a doctor provided reasons why the patented procedure wasn't obvious.

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