The patent at issue in the case covers the active ingredient in Nasonex, mometasone furoate monohydrate.
The patent provides exclusivity for this form of mometasone until 3 April 2018. Apotex is seeking FDA approval to market generic Nasonex.
Merck executive vice president and general counsel Bruce Kuhlik said the company believes the patent for Nasonex in the US is valid and would be infringed by the Apotex product.
"Today’s decision reflects just one step in the lengthy patent litigation process, and we plan to review all of our options, including a likely appeal of the decision," Kuhlik added.
Judge Peter Sheridan presided over the trial. The law firms Weil, Gotshal & Manges and Gibbons represented Merck.