IP Law Daily Weight loss drug patent claims invalid as obvious
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Thursday, August 15, 2019

Weight loss drug patent claims invalid as obvious

By Jody Coultas, J.D.

Although the patents covering Contrave® contained an adequate written description, the weight loss properties of the drug were well known to the industry prior to the issuance of the patent.

The U.S. Court of Appeals for the Federal Circuit has affirmed-in-part and reversed-in-part a decision in a patent infringement suit involving patents held by Nalpropion Pharmaceuticals, Inc. for the weight management drug Contrave®. In a suit alleging that Actavis Laboratories FL, Inc. infringed Nalpropion’s patents covering Contrave®, the appellate court concluded that the written descriptions were adequate. However, two of the patent claims at issue were determined to be invalid as obvious in light of prior art (Nalpropion Pharmaceuticals, Inc. v. Actavis Laboratories FL, Inc., August 15, 2019, Lourie, A.).

Nalpropion holds U.S. Patent Nos. 7,375,111 (the ’111 patent), 7,462,626 (the ’626 patent), and 8,916,195 (the ’195 patent) for Contrave®, a weight management drug for overweight or obese adults. The ’195 and ‘626 patents are directed to methods of treating overweight or obesity, while the ’111 patent is directed to a composition of sustained-release bupropion and naltrexone for affecting weight loss. Actavis filed an Abbreviated New Drug Application (ANDA) seeking to market a generic version of Contrave® prior to the expiration of the patents in suit. Nalpropion filed infringement claims, while Actavis counterclaimed for invalidity.

The federal district court in Wilmington, Delaware held that Actavis’s proposed naltrexone hydrochloride and bupropion hydrochloride extended-release tablets would infringe claim 1 of the ’111 patent), claims 26 and 31 of the ’626 patent, and claim 11 of the ’195 patent; (2) the asserted claims were not invalid; (3) the effective date of any FDA approval of the Contrave® ANDA shall be no earlier than the latest expiration of the ’111, ’626, and ’195 patents; and (4) Actavis was permanently enjoined from manufacturing, using, or selling its ANDA product before the expiration of the patents in suit.

Written description. Actavis failed to present clear and convincing evidence that claim 11 of the ’195 patent was invalid for lack of adequate written description, the appellate court held. In support for its conclusion that the ‘195 patent contained an adequate written description, the district court found that the values in Table 10—67% release in one hour and 85% release in two—fell squarely within the claimed range in claim 11 and that the lower bounds were supported by the dissolution data for the 15% HPMC formulation in Table 5. Actavis argued that both inventor and expert testimony demonstrated that the two dissolution methods would produce different results, and that Table 5 cannot support the claimed range because a person of ordinary skill in the art would not appreciate that the 15% HPMC data were relevant to the claims. The district court, in crediting Nalpropion’s experts over experts for Actavis, performed its fact-finding function properly, and the appellate court declined to disturb the finding. "While as a general matter written description may not be satisfied by so-called equivalent disclosure, in this case, buttressed by the district court’s fact-finding, and where the so-called equivalence relates only to resultant dissolution parameters rather than operative claim steps," the appellate court affirmed the district court’s conclusion.

Obviousness. The appellate court concluded that the district court erred in holding that claims 26 and 31 of the ’626 patent and claim 1 of the ’111 patent were not invalid. Actavis argued that a prior patent and a research paper rendered the claims obvious. The district court concluded that, because a person of skill would not understand bupropion’s mechanism of action and because of its modest effectiveness, a person of skill would not have found bupropion to be an obvious starting point for further study. Also, the district court concluded that a person of skill would not have understood naltrexone to be effective for weight loss. However, the appellate court sided with Actavis in holding that the prior art disclosed the claimed components of the composition claims and the steps of the method claims including the use claimed by the method. There was sufficient evidence that prior art references taught that bupropion causes weight loss, with even a named inventor of the ’626 and ’111 patents confirming that bupropion had been considered safe and had weight loss effects. Also, there was sufficient prior references to show that naltrexone could cause weight loss. Finally, the appellate court found that every limitation in the claims at issue was met by prior art references.

Dissent. A dissenting judge would have held claim 11 of the ’195 patent invalid for lack of adequate written description, arguing that the majority created a new rule to the written description jurisprudence. Specifically, the judge argues that the majority held that a "substantially equivalent" disclosure may satisfy the written description requirement when the relevant claim limitation recites only "resultant dissolution parameters rather than operative claim steps," which was not in line with the law.

This case is No. 2018-1221.

Attorneys: Dominick A. Conde (Venable LLP) for Nalpropion Pharmaceuticals, Inc. Jonathan D. Ball (Greenberg Traurig LLP) for Actavis Laboratories FL, Inc.

Companies: Nalpropion Pharmaceuticals, Inc; Actavis Laboratories FL, Inc.

MainStory: TopStory Patent FedCirNews

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