NEW YORK (AP) -- Trading of Pfizer Inc. stock was halted briefly in Wednesday trading on news that a court has invalidated a patent for one of its top-selling medicines, potentially opening the door for cheaper generic versions 18 months sooner than expected.
Pfizer, the world's second-biggest drugmaker, says it disagrees with the ruling and will "pursue all available remedies," including appealing the court's decision.
The case involves a reissued patent that would prevent U.S. sales of generic versions until December 2015. Five makers of generic drugs are seeking Food and Drug Administration permission to sell generic Celebrex starting on May 30, when the arthritis drug's original patent expires.
New York-based Pfizer sued the five companies, alleging patent infringement. But the U.S. District Court for Virginia's Eastern District ruled the reissued patent isn't valid.