‘Substantially Equivalent’ Disclosure May Satisfy Written Description Requirement Under Certain Circumstances

“A ‘substantially equivalent’ disclosure may satisfy the written description requirement when the equivalence relates only to nonlimiting parameters rather than to operative claim steps.”

Federal CircuitThe Federal Circuit recently affirmed in part and reversed in part a district court decision holding that Actavis Laboratories FL, Inc.’s (“Actavis’s”) generic Abbreviated New Drug Application (“ANDA”) product infringed claims of patents owned by Nalpropion Pharmaceuticals (“Nalpropion”) and that the asserted claims were not invalid. See Nalpropion Pharms., Inc. v. Actavis Labs. FL, Inc., No. 2018-1221, 2019 U.S. App. LEXIS 24281 (Fed. Cir. Aug. 15, 2019) (Before Prost, Chief Judge, Lourie and Wallach, Circuit Judges) (Opinion for the Court, Lourie, Circuit Judge) (Dissent-in-part, Prost, Chief Judge).

The Court found that the district court did not err in finding that Nalpropion’s U.S. Patent No. 8,916,195 (“the ’195 patent”) was not invalid for lack of written description, but that the district court did err in finding that the asserted claims of U.S. Patent Nos. 7,375,111 (“the ’111 patent”) and 7,462,626 (“the ’626 patent”) were not obvious in view of the prior art.

Agreement with the District Court

The patents at issue are directed toward weight management in overweight adults via administration of effective amounts of bupropion and naltrexone. Actavis filed an ANDA to sell a generic version of Nalpropion’s product Contrave prior to the expiration of Nalpropion’s patents. Nalpropion brought suit for patent infringement, and Actavis in turn challenged the asserted claim of the ’195 patent as invalid for lack of written description and the asserted claims of the ’111 and ’626 patents as invalid for obviousness. The district court determined that all asserted claims were not invalid and were infringed.

The Federal Circuit agreed that the ’195 patent was not invalid for lack of written description. The asserted claim of the ’195 patent contained language regarding a “dissolution profile of a dissolution test of USP Apparatus 2 Paddle Method.” Actavis argued that the claim lacked adequate written description because the claimed dissolution profile was achieved using the USP Apparatus 2 Paddle Method (“USP 2”), but the specification disclosed data that was obtained using the different USP Apparatus 1 Basket Method (“USP 1”).

The district court concluded on the facts that USP 1 and USP 2 were “substantially equivalent,” and therefore the specification showed that the inventors possessed the invention irrespective of the method of measurement used. The Federal Circuit did not disturb this finding, noting that “‘[t]he test for sufficiency is whether the disclosure of the application relied upon reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.’ It is not necessary that the exact terms of a claim be used in haec verba in the specification, and equivalent language may be sufficient.” The Court found that the district court’s findings were supported by the record and so concluded that:

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, we affirm the district court’s conclusion. Rigidity should yield to flexible, sensible interpretation.

Reversed on Obviousness

With respect to the obviousness of the ’111 and ’626 patents, however, the Court disagreed with the district court’s nonobviousness decision. The Federal Circuit reversed, finding that the claims were obvious in light of the prior art, which would have motivated a person of ordinary skill in the art to combine bupropion and naltrexone for weight loss given that both drugs had shown weight loss effects and were administered in combination in the prior art to minimize weight gain.

Prost Disagrees

Chief Judge Prost dissented in part with respect to the majority’s written description determination, stating that the majority appeared to add a “new rule” that “written description for nonlimiting clauses may be satisfied by disclosure that is ‘substantially equivalent’ even though the same disclosure would not be sufficient for limiting clauses.” She argued that the ’195 patent should be found invalid because the claimed use of the USP 2 standard for measuring the dissolution was a limiting clause not disclosed by the specification, which instead disclosed USP 1. Judge Prost noted that there was no record evidence to support that USP 1 and USP 2 were substantially equivalent, and that while teachings relating to USP 1 might render USP 2 obvious, this was not the standard for a sufficient written description. Therefore, Judge Prost found that the majority’s determination did not comport with the law and dissented from the written requirement section of the majority’s opinion.


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