Beginning in 2011, Purdue Pharma and Grunenthal GmbH filed Hatch-Waxman lawsuits against Teva Pharmaceuticals, Amneal Pharmaceuticals, Epic Pharma and Mylan Pharmaceuticals in response to their Abbreviated New Drug Applications seeking Food and Drug Administration approval to market generic versions of OxyContin.
After a three-week bench trial in the Teva case, the district court ruled that all of the asserted patent claims are invalid. The district court then entered orders of dismissal in the cases against Amneal, Epic and Mylan based on collateral estoppel. Purdue and Grunenthal appealed the final judgment in the Teva case and the dismissal orders in the Amneal, Epic and Mylan cases.
On appeal, the Federal Circuit affirmed the district court’s invalidity determinations. The Court of Appeals rejected Purdue’s argument that its discovery of the source of the toxic impurity minimized in its claimed drug product supported patentability because the solution did not depend on the source of the impurity. The Federal Circuit also affirmed the district court’s dismissal of the actions against Amneal, Epic and Mylan for collateral estoppel because Purdue did not present any persuasive reasons why the Teva invalidity ruling should not apply to the other cases.
The Federal Circuit denied Purdue’s petition for panel rehearing and rehearing en banc.
Purdue Pharma L.P. v. Epic Pharma, LLC, No. 14-1294 (Fed. Cir.).