IMPAX LABS. INC. v. LANNETT HOLDINGS INC.
In an appeal taken from the Delaware district court, the Federal Circuit extended deference to the district court’s decision to uphold validity of two patents despite a specific, albeit brief, teaching of the claimed pharmaceutical formulation in a prior art reference. The patents at issue claimed formulations for intranasal administration of having zolmitriptan as the active ingredient. The Federal Circuit affirmed the district court’s decision that a second prior art reference “taught away” from the claimed formulation by teaching that a metabolite of zolmitriptan was more effective than zolmitriptan for intranasal applications. Though it found this to be a “close case,” the appellate court found that under the deferential “clearly erroneous” standard of review, the district court’s ruling had sufficient support in the evidence to avoid reversal.
AstraZeneca markets an intranasal zolmitriptan formulation under the brand name Zomig® (zolmitriptan) Nasal Spray for the treatment of migraines. In June 2014, Lannett notified AstraZeneca that it had filed an ANDA seeking approval for a generic version of Zomig® Nasal Spray. Its Paragraph IV certification alleged noninfringement and/or invalidity of the asserted patents. AstraZeneca responded by filing suit in the District of Delaware for infringement of the asserted patents. After the bench trial, the parties stipulated that Lannett’s product, if approved by the FDA, would infringe the asserted patents.
On appeal, the primary issue addressed by the Federal Circuit was whether it would have been obvious to make zolmitriptan into a nasal spray. Lannett’s main argument was that the district court erred in concluding that the prior art taught away, thus causing it to disregard express teachings in the prior art disclosing intranasal formulations of zolmitriptan. The Federal Circuit held that the prior art should be viewed as a whole and that in this case, the allegedly invalidating prior art was not primarily directed to intranasal formulations of zolmitriptan and in fact “barely mentioned” such formulations. Further, it held that it did “not find that the court clearly erred in concluding that at the time, zolmitriptan’s known significant reliance on its active metabolite would have, on balance, dissuaded a person of skill in the art from making nasal formulations of zolmitriptan.”
The Federal Circuit also reviewed the district court’s findings regarding objective indicia of nonobviousness, and specifically, a 2012 license agreement between Impax and AstraZeneca covering the Zomig® products for which Impax paid $130 million. The Court held that there was an adequate nexus between the intranasal patents and $130 million, and that the District Court did not clearly err in finding that a part of the 2012 agreement was attributable to the ’237 patent and the ’767 patent.
Ultimately, while the Federal Circuit acknowledged that this “case was close,” it concluded that the decision was supported by factual findings, which were not clearly erroneous, and that Lannett failed to prove by clear and convincing evidence that the claims of the asserted patents are invalid.
Opinion can be found here.
