Par cleared but Watson liable over Novartis patents

A US appeals court has issued a mixed judgment in a patent dispute that saw Novartis file infringement claims against both Watson Pharmaceuticals and Par Pharmaceutical.

In a unanimous 3-0 verdict, the US Court of Appeals for the Federal Circuit ruled on Thursday (May 21) that two Novartis patents, which cover treatments for patients with Alzheimer’s and Parkinson’s disease, are valid after Watson challenged their validity.

The court said Watson had infringed the patents through its generic versions of Novartis’s Exelon (rivastigmine) drug but that Par, which had also proposed generic versions of the drug, did not infringe them.

The dispute concerned two patents, US numbers 6,316,023 and 6,335,031, both of which are directed to Exelon.

Both disputes were ruled on separately at the US District Court for the District of Delaware but were consolidated by the federal circuit because they concerned the same patents.

In 2011, the US Food and Drug Administration (FDA) approved Novartis’s application to market 4.6 mg and 9.5 mg doses of the drug.

The FDA also approved Watson’s and Par’s Abbreviated New Drug Applications (ANDAs) to market generic versions of the drug in the same year. Shortly after, Novartis sued both companies for infringement.

In 2012 the FDA also approved another Novartis application for a 13.3 mg dose of the drug. This was followed by ANDAs from Par and Watson for generic versions with the same dosage strength.

Novartis then amended its previous lawsuit to include the latest ANDAs.

The district court ruled last year that Watson’s generic versions of the drug infringed Novartis’s  patents, but Par’s did not.

In both cases, the patents were found to be valid, despite challenges from Watson that they were obvious.

Watson and Novartis appealed against both judgments, but the federal circuit backed the district court’s decisions.

“Because the district court did not err in concluding that the patents are not invalid, and additionally did not clearly err in finding that the patents were not infringed by Par’s ANDA product, we affirm the district court’s judgments,” the federal circuit concluded.

Novartis, Watson and Par had not responded to a request for comment at the time of publication.