IP Law Daily OxyContin patent claims invalid as obvious, anticipated over prior art
Monday, February 1, 2016

OxyContin patent claims invalid as obvious, anticipated over prior art

By Jody Coultas, J.D.

Patent claims covering the pharmaceutical drug OxyContin® were invalid as obvious in light of prior art, according to the U.S. Court of Appeals for the Federal Circuit (Purdue Pharma L.P. v. Epic Pharma, LLC, February 1, 2016, Prost, S.). A district court’s obviousness determination, and subsequent dismissal of related cases on the basis of collateral estoppel, was upheld.

A reformulated version of OxyContin® is covered by U.S. Patent Nos. 7,674,799 (the ’799 patent), 7,674,800 (the ’800 patent), 7,683,072 (the ’072 patent) (collectively, the low-ABUK patents), and 8,114,383 (the ’383 patent). The low-ABUK patents recite an improved formulation of OxyContin; specifically, an oxycodone salt with extremely low levels of a particular impurity, 14-hydroxycodeinone (“14-hydroxy”). The ’383 patent covers abuse-resistant formulations. Purdue Pharma L.P., The P.F. Laboratories, Inc., Purdue Pharmaceuticals L.P., Rhodes Technologies, and Grunenthal GmbH assert ownership of the patents.

Amneal Pharmaceuticals, LLC, Epic Pharma, LLC, Mylan Pharmaceuticals Inc., Mylan Inc., and Teva Pharmaceuticals USA, Inc. all filed Abbreviated New Drug Applications (ANDAs) seeking to sell generic versions of the reformulated OxyContin®.

A district court found that the asserted claims were infringed by Teva’s proposed generic product, but held that all of the claims were invalid as anticipated by or obvious over the prior art. Purdue stated that it intended to appeal the Teva decision but it agreed that the district court’s decision regarding the invalidity of the low-ABUK patents precluded its claims for relief against the other defendants. Therefore, the remaining actions against Amneal, Epic, and Mylan were dismissed based on collateral estoppel. Purdue and Grunenthal appealed.

Invalidity of low-ABUK patents. The district court held that the claims were obvious based on prior art that taught that oxidation of thebaine produced 14-hydroxy and that it was well known in the art that 14-hydroxy could be removed using hydrogenation. The court also determined that the discovery of 8α was not necessary to the claimed invention, and that the claim limitation requiring that the remaining 14-hydroxy is at least in part “derived from 8α[]” is a product-by-process limitation and thus immaterial in the obviousness determination.

The asserted claims of the low-ABUK patents were obvious and the district court did not err in its determination of obviousness, according to the court. Purdue argued that the court failed to properly credit the discovery of 8α as the core of the claimed inventions. However, identification of the source of the remaining 14-hydroxy as being 8α had no effect on the structure or nature of the low-ABUK oxycodone product. It would be obvious to a person of ordinary skill in the art to use hydrogenation to remove the excess 14-hydroxy in the oxycodone active pharmaceutical ingredient. The claim requirement that the remaining 14-hydroxy be “derived from 8α[]” did not describe the structure of 14-hydroxy and thus was a process limitation. Therefore, the district court did not err in disregarding the limitation in its obviousness analysis.

It was not err for the district court to dismiss Purdue’s arguments regarding secondary considerations, according to the court. There was no clear nexus between the low-ABUK product of the patents and the commercial success of Purdue or Rhodes. There was also insufficient evidence to support Purdue’s arguments regarding failure of others, long-felt but unaddressed need, and praise from competitors.

Invalidity of the ‘383 patent. The ‘383 patent was invalid as anticipated by prior art, according to the court. The district court found that a prior art reference disclosed opioid formulations and that it inherently disclosed tablets with a breaking strength in excess of 500 N, as required by the asserted claims. Grunenthal argued that the prior art did not describe formulations that contain opioids such as oxycodone, but this reading was too narrow in the court’s view. Allegations that the defendants’ expert witness was not reliable and failed to present adequate evidence were also dismissed as unfounded. Finally, Grunenthal argument that the district court erred by using distinct sections of the prior art and reassembling them into an embodiment to find that all of the limitations were present was without merit. Because the district court’s assessment was persuasive and not clearly erroneous, it was upheld.

Collateral estoppel. The district court’s dismissal on the basis of collateral estoppel was upheld by the court. Purdue did not present any persuasive argument on appeal as to why collateral estoppel should not apply.

The cases are Nos. 2014-1294, 2014-1296, 2014-1306, 2014-1307, 2014-1311, 2014-1312, 2014-1313, and 2014-1314.

Attorneys: Gregory A. Castanias (Jones Day) for Purdue Pharma L.P., The P.F. Laboratories, Inc., Purdue Pharmaceuticals L.P., and Rhodes Technologies. Basil J. Lewris (Finnegan, Henderson, Farabow, Garrett & Dunner, LLP) for Grunenthal GmbH. William A. Rakoczy (Rakoczy Molino Mazzochi Siwik LLP) for Mylan Pharmaceuticals Inc. and Mylan Inc. Barbara Mullin (Akin, Gump, Strauss, Hauer & Feld, LLP) for Amneal Pharmaceuticals, LLC. Mark David Schuman (Carlson, Caspers, Vandenburgh, Lindquist & Schuman, P.A.) for Teva Pharmaceuticals USA, Inc.

Companies: Purdue Pharma L.P.; The P.F. Laboratories, Inc.; Purdue Pharmaceuticals L.P.; Rhodes Technologies; Grunenthal GmbH; Mylan Pharmaceuticals Inc.; Mylan Inc.; Amneal Pharmaceuticals, LLC; Teva Pharmaceuticals USA, Inc.

MainStory: TopStory Patent FedCirNews

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