Court upholds validity of Merck's Singulair patent

NEW YORK (Reuters) - A U.S. federal judge has upheld the validity of a patent on Merck & Co Inc's (MRK.N) asthma and allergy drug Singulair, dealing a blow to Teva Pharmaceutical Industries Ltd (TEVA.TA), which had sought to introduce a generic copy.

Merck's shares rose 1.4 percent to $31.14. Teva's shares rose 0.7 percent to $51.14.

The ruling found that Teva had infringed Merck's patent and ordered that a permanent injunction be issued restraining Teva from manufacturing or selling a generic version of Singulair -- Merck's biggest-selling product -- until the patent expires in 2012.

Teva had challenged the validity of patent '473 during a trial in February before Judge Garrett Brown in Newark federal court in New Jersey.

Had Teva prevailed, its generic version would have blown a hole in Singulair's annual U.S. sales of about $3 billion.

(Reporting by Ransdell Pierson, editing by Gerald E. McCormick)