Last week, the United States Court of Appeals for the Federal Circuit denied a petition for rehearing en banc in HZNP Finance Limited v. Activis Laboratories UT, Inc., Nos. 2017-2149, -2152, -2153, -2202, -2203, -2206 (Feb. 25, 2020). The petition sought rehearing after a three-judge panel of the Federal Circuit affirmed a decision from the District of New Jersey finding claim 49 of HZNP’s U.S. Patent No. 8,252,838 (“the ’838 patent”) invalid as indefinite under 35 U.S.C. § 112.
The ’838 patent is directed to an analgesic formulation containing the active ingredient diclofenac. Claim 49 recites a topical formulation “consisting essentially of” diclofenac and other ingredients. The district court found that, in the context of the ’838 patent, the transitional phrase “consisting essentially of” was indefinite. Under Federal Circuit jurisprudence, that transitional phrase indicates that the invention must include the identified ingredients, and may include other ingredients, but only if the other ingredients do not materially affect the basic and novel properties of the invention. The district court found that one of the asserted novel properties of the claimed formulation, “better drying time,” was not sufficiently described in the specification, rendering claim 49 indefinite. On appeal, a panel of the Federal Circuit affirmed. HZNP petitioned for rehearing en banc.
In a summary per curiam order, the Federal Circuit denied HZNP’s petition. Judge Lourie, joined by Judges Newman, O’Malley, and Stoll, issued a written opinion in dissent. Judge Lourie explained he believed the panel erred in evaluating the definiteness requirement of § 112. Specifically, he asserted that, because the novel property of “better drying time” was discussed only in the specification, and not actually recited in claim 49, any alleged lack of clarity in the meaning of the term “better drying time” cannot provide a valid basis for finding claim 49 indefinite. Judge Lourie urged that “it is the language of the claims that must not be indefinite, not the understanding or clarity of an advantage of the invention.” Judge Lourie noted that the precise meaning of “consisting essentially of” in a patent infringement suit should boil down to the fact question of whether the presence of an unrecited ingredient in an accused product is in fact inconsistent with, or defeats the purpose of, the claimed composition. But, he stated, “the fact that one generally has to determine this question at trial does not make the claim indefinite.”