TRENTON, New Jersey (AP) -- Trading of Pfizer Inc. stock was halted briefly Wednesday afternoon due to news that a federal court had invalidated the key patent for one of its most lucrative medicines, potentially opening the door for cheaper generic versions 18 months sooner than expected.
Pfizer, the world's second-biggest drugmaker, said in a statement that it disagrees with the ruling and will "pursue all available remedies," including immediately appealing the court's decision.
Celebrex, Pfizer's fourth-bestselling product, brought in $2.9 billion in worldwide sales last year. The anti-inflammatory pill is widely used for arthritis and acute pain.
Trading of Pfizer shares was halted for 20 minutes on the New York Stock Exchange, "pending the release of material news." Trading resumed shortly after Pfizer released a statement that it would fight the ruling. Shares dipped 29 cents when trading resumed, with volume picking up sharply. Shares closed at $31.97, down 45 cents or 1.4 percent, but still near Pfizer's 52-week high.
The case involves a reissued patent that would prevent U.S. sales of generic versions until Dec. 2, 2015. Five makers of generic drugs are seeking Food and Drug Administration permission to sell generic Celebrex starting on May 30, when the drug's original patent expires.
New York-based Pfizer sued the five companies, alleging patent infringement. But on Wednesday, U.S. District Judge Arenda Allen of Virginia's Eastern District in Norfolk ruled the reissued patent isn't valid.
The lawsuit had been scheduled for a trial beginning on March 19, but last week the judge notified the parties that she would rule on motions they had filed in the case, instead of holding a trial.