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DOE Not Foreclosed Where Qualitative Claim Limitation Is Given a Quantitative Construction

September 28, 2012

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Last Month at the Federal Circuit - October 2012

Judges: Newman, Clevenger (dissenting-in-part), Wallach (author)

[Appealed from: E.D. Tex., Judge Davis]

In Pozen Inc. v. Par Pharmaceutical, Inc., Nos. 11-1584, -1585, -1586 (Fed. Cir. Sept. 28, 2012), the Federal Circuit affirmed the district court’s decision that the patents-in-suit were not invalid for obviousness or inadequate written description, and that they were infringed under the DOE.

Pozen Inc. (“Pozen”) markets Treximet®, a combination of sumatriptan, which is a 5-HT receptor agonist, and naproxen, a well-known nonsteroidal anti-inflammatory drug (“NSAID”). Pozen holds three related patents (“the patents-in-suit”): U.S. Patent Nos. 6,060,499 (“the ’499 patent”), directed to a method of treating migraines comprising cotimely administration of 5-HT agonists and long-acting NSAIDs; 6,586,458 (“the ’458 patent”), a continuation of the ’499 patent directed to methods and compositions combining 5-HT agonists and long-acting NSAIDs; and 7,332,183 (“the ’183 patent”), directed to a multilayer pharmaceutical tablet with a triptan, such as sumatriptan, and an NSAID in separate layers that dissolve independently.

Pozen sued Par Pharmaceutical, Inc., Alphapharm Pty Ltd., and Dr. Reddy’s Laboratories, Inc. (collectively “Par”) based on Par’s filing of an ANDA to market a generic version of Treximet® before the expiration of the patents-in-suit. The district court determined that the asserted claims were not invalid for anticipation, obviousness, or inadequate written description, and that the ANDA products were infringing. The district court thus enjoined Par from making or selling the ANDA products. Par appealed.

On appeal, the Federal Circuit agreed with the district court that the prior art would not have provided one of ordinary skill in the art with motivation to combine sumatriptan and naproxen in order to benefit from longer lasting efficacy as compared to when either agent is taken alone. The Court held that Par failed to rebut the presumption of validity afforded issued patents by clear and convincing evidence, and that the patents-in-suit were thus not invalid for obviousness.

Regarding written description, the Federal Circuit held that the district court did not clearly err in finding there was adequate written description to support the ’499 patent. The Court reasoned that the specification met the requirement because it described the invention in such a way that it is understandable to a person of ordinary skill in the art. The Court agreed with the district court that the limitations “therapeutic package,” “finished pharmaceutical container,” and “said container further containing or comprising labeling directing the use of said package in the treatment of migraine” were supported, because “persons of skill in the art would know [that the disclosed] pharmaceutical dosages are administered to a patient in containers or packages with labeling and inserts with dosage instructions.” Slip op. at 23-24 (quoting Pozen Inc. v. Par Pharm., Inc., 800 F. Supp. 2d 789, 821 (E.D. Tex. 2011)).

Turning to infringement, the Federal Circuit held that the district court did not err in finding that the ANDA products infringed the ’183 patent under the DOE. The Court rejected Par’s argument that the products did not meet the “independent dissolution” and “substantially all” limitations. For the “independent dissolution” limitation, the Court explained that “[a]lthough there is no direct evidence comparing the rate of dissolution of the ANDA products to that of the agents individually, no such actual comparison was necessary.” Id. at 28. “Under the doctrine of equivalents analysis[,] Pozen need only show that the ANDA products performed the same function in the same way to achieve the same result as the claimed elements of the ’183 patent.” Id.

For the “substantially all” limitation, the Court first held that the DOE could apply to the limitation. “[A]lthough the claim language itself is a qualitative measure, the claim construction pulls directly from the specification to give the term ‘substantially all’ a quantitative definition, specifically, ‘at least 90%, and preferably greater than 95%’ . . . .” Id. at 31 (citation omitted). “[T]his court has previously concluded that the doctrine of equivalents is not foreclosed with respect to claimed ranges.” Id. (citing Adams Respiratory Therapeutics, Inc. v. Perrigo Co., 616 F.3d 1283, 1291-92 (Fed. Cir. 2010)). The Court thus applied the DOE and held that a tablet layer with 85% of the agent can be fairly characterized as an insubstantial change from a tablet layer with 90% of the agent. The Court affirmed the district court’s decision that the ANDA products infringed the “substantially all” limitation under the DOE.

Judge Clevenger dissented-in-part, stating that the Court erred in sustaining the district court’s judgment that the “substantially all” limitation was infringed under the DOE. Judge Clevenger characterized the issue as a question of “whether 85% can be ‘substantially all’ given the District Court’s construction of the limitation.” Clevenger Dissent at 4. In Judge Clevenger’s view, Pozen and the district court avoided answering the question by using the notion of an equivalent layer. Judge Clevenger stated that a layer cannot be equivalent if it is numerically nonequivalent, and that he disagreed with the majority’s determination that “a reasonable person could determine that a tablet layer with 85% of the agent is within the scope of the doctrine of equivalents.” Id. at 5.

Summary authored by Benjamin A. Saidman, law clerk at Finnegan.