Patent office reviews Singulair again

Merck's blockbuster allergy-and-asthma drug Singulair got a double whammy today, competition-wise. Mylan Pharmaceutical won tentative FDA approval for its version of the drug, which accounted for 18 percent of Merck's 2008 sales. And the U.S. Patent and Trademark Office ordered a key patent on the drug to be re-examined.

As you know, Teva Pharmaceutical Industries, in typical Teva fashion, has been challenging Singulair's patent protection in court because it's ready to sell its own versions of the drug. The patent office's inquiry threatens Singulair exclusivity from a different direction--but presents the same risk. If either challenge succeeds, Merck would have to scramble to make up billions in revenue from the drug, several years earlier than it had anticipated. The drug's patents are due to expire in 2012, the Wall Street Journal reports.

Patent office documents say that a New York company asked it to check out the Singulair patent, raising "a substantial new question of patentability." That request cited info that hadn't been considered when the office reviewed Merck's patent app back in the '90s, the newspaper says. Among that info was a paper written by a Merck scientist.

- read the WSJ story
- check out the Mylan announcement