Merck Could Lose Patent on Key Drug Singulair

Merck & Co. could lose early it's exclusive right to market Singulair, a successful allergy treatment with patent protection set to expire in 2012, if the U.S. Patent and Trademark Office finds that key discoveries that led to the drug were made obvious by prior research, or if Merck is revealed to have withheld information in its patent application, the Wall Street Journal reports.

The patent office has ordered a re-examination of a key patent for this blockuster drug, "saying new questions have been raised about its 'patentability.'" The re-examination "represents a separate avenue that could clear the way for early generic competition for Singulair, which had $4.3 billion in world-wide sales last year, or 18% of Merck sales."

Merck was previously sued by Teva Pharmaceutical Industries for the right to sell a mimicked version of the drug, the Journal reports. However, an independent company, Article One Partners, filed the request for the new patent office review after turning up research by a Merck scientist that was not included in the application (Loftus, 5/29).