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Impax, AstraZeneca Get Win in Generic Zomig Patent Case

A Delaware federal judge has given a victory to Impax Laboratories Inc. and AstraZeneca AB in their patent infringement suit over Lannett Holdings Inc.’s planned generic version of the migraine medication Zomig, upholding the validity of two patents Lannett conceded it infringed.

The Wednesday decision by U.S. District Judge Richard Andrews, issued following a bench trial held in September, effectively bars Lannett from launching its version of Zomig.

AstraZeneca owns the two patents on a nasal spray formulation of the drug zolmitriptan and licensed them to Impax for use in Zomig. The patents expire in November 2020, but have exclusivity for pediatric use until May 2021.

After Lannett was sued for infringement, it argued that the patents are invalid as anticipated or obvious, but Judge Andrews rejected those arguments. He ruled that the prior art did not anticipate the claimed invention and that because the prior art taught away from using zolmitriptan as a nasal spray, the patents were not obvious.

“Given what was known about how zolmitriptan worked, a skilled artisan would not have had a reasonable expectation of success in combining zolmitriptan in a nasal spray,” the judge concluded.

Lannett stipulated that it infringed the patents, so the main issue at the trial was validity. The judge noted that Lannett did not concede infringement until after the trial, which “wasted everyone's time for no apparent reason,” since the plaintiffs were required to put on unnecessary testimony on infringement.

The obviousness case hinged on a unique attribute of zolmitriptan, the judge wrote. The drug has a powerful metabolite, the creation of which is delayed and diminished when it is administered nasally, rather than ingested.

While that would appear to be a detriment and would point skilled artisans away from using the drug as a nasal spray, Zomig is effective when administered that way, the judge found.

“This teaching away demonstrates that the … patents were not obvious,” he concluded.

With regard to anticipation, the judge found that the prior art cited by Lannett did not disclose key aspects of the Zomig patents.

Lannett also argued that Impax and AstraZeneca did not have standing to bring the suit. The judge found that “there is no reason to believe” that they lacked standing, but said that “out of an abundance of caution,” Lannett could request to have an AstraZeneca executive testify live on that issue if it wished.

“We are pleased with the court's decision upholding the validity of the patents for Zomig Nasal Spray,” Paul Bisaro, president and CEO of Impax, said in a statement. “We look forward to continuing to supply this product to patients and will continue to actively protect our intellectual property.”

An attorney for Lannett could not immediately be reached for comment Monday.

Impax and AstraZeneca have also sued Par Pharmaceutical Inc. in Delaware over its planned generic version of Zomig. Judge Andrews stayed that case pending the outcome of the Lannett case.

The patents-in-suit are U.S. Patent Numbers 6,750,237 and 7,220,767.

Impax and AstraZeneca are represented by Jim Hurst, Marcus E. Sernel, Alyse Wu, Stefan M. Miller, Ashley Borom and Sam Kwon of Kirkland & Ellis LLP, and Steven Balick, Tiffany Geyer Lydon and Andrew Mayo of Ashby & Geddes.

Lannett is represented by Joseph Posillico, Frank Carroll, Michael Glynn, Seth Niederman and Austen Endersby of Fox Rothschild LLP.

The case is Impax Labs Inc. et al. v. Lannett Holdings Inc., case number 1:14-cv-00984, in the U.S. District Court for the District of Delaware.