Pfizer Inc. has recently seen how sales of its biggest-selling drug, anti-cholesterol medication Lipitor, started falling when it had to compete with cheaper generic versions. The pharmaceutical giant was determined not to let that happen to its number-two cash cow, anti-pain and seizure drug Lyrica.

On July 18, Pfizer turned aside a challenge from eight generic drug companies seeking to invalidate three patents relating to Lyrica. The patents, which were held by Northwestern University, had been granted to Pfizer under an exclusive license. Led by Teva Pharmaceutical Industries Ltd., the world’s largest generic-drug manufacturer, the challengers had hoped to make cheaper versions of the drug immediately, and had filed abbreviated new drug applications with the Federal Drug Administration. White & Case and Morris, Nichols, Arsht & Tunnell represented Pfizer, while McCarter & English represented Northwestern. Teva, meanwhile, was represented by Kenyon & Kenyon.

In a 133-page decision, U.S. District Judge Gregory Sleet in Wilmington, Del., held that the patents were valid and enforceable, giving Pfizer exclusivity until Dec. 30, 2018. The decision came nine months after a bench trial in which Sleet issued a partial verdict in favor of Pfizer and Northwestern, finding that the patents were neither anticipated by prior art nor obvious.

After post-trial briefing, Sleet reiterated his finding that the patents were valid and that the proposed generic products infringed on the Lyrica patents. The generics had argued that one patent covering the chemical compound in Lyrica was obvious and anticipated by three prior compounds. However, Sleet found that it was not obvious to apply those prior compounds for use in treating seizures and noted that finding reliable anti-seizure drugs is difficult and unpredictable. As to a second patent, which covers methods used to treat pain with the compound in Lyrica, Sleet again rejected the generics’ contention that it was obvious because anticonvulsants were generally used to treat certain types of pain. Instead, Sleet agreed with Pfizer that the most common anticonvulsant drugs at the time were ineffective in treating pain and, in some cases, actually increased it. Finally, the generics had argued that the third patent, which covers methods used to treat seizures using the compound in Lyrica, was invalid because the date on the patent came after that of a prior filing involving the compound. Sleet, however, accepted Pfizer’s argument that it had properly filed a certificate of correction fixing the date so that it was no longer anticipated.

Attorneys for Pfizer, Jack Blumenfeld of Morris Nichols and Dimitrios Drivas of White & Case, referred comments to their client. “The court’s decision recognizes the infringement and validity of our Lyrica patents and affirms the value of Lyrica as a distinct and important innovation for patients,” Amy Schulman, Pfizer’s general counsel, said in a statement. Northwestern’s attorney, Michael Kelly of McCarter & English, declined comment. Kenyon & Kenyon counsel James Galbraith, who represented Teva, did not respond to a request for comment.

Victor Li is a reporter for The American Lawyer, a Legal affiliate based in New York. This article first appeared on The Am Law Litigation Daily at •