Fall 2014
AIPLA Chemical Practice Chronicles Newsletter
By Paul W. Browning, Ph.D.; Clara N. Jiménez
Authored by Paul W. Browning, Ph.D. and Clara N. Jiménez
Developing a new chemical entity and then bringing the associated new drug to market is an expensive and time consuming process. Strong patent protection is therefore particularly important for patent owners in the pharmaceutical industry. And, while protecting methods of making and using inventive products is important, product claims usually provide the strongest and broadest protection for patent owners, allowing enforcement against anyone who makes, uses, sells, or imports into the U.S. the patented product before the expiration of the patent term. 35 U.S.C. § 271.
To ensure broad protection of its inventions, a patentee may pursue product claims encompassing a range of potential embodiments of the invention, including alternative chemical forms, such as salts, polymorphs and solvates, as the latter may be explored and pursued by potential infringers. Claims broadly directed to a variety of chemical forms may later be challenged, however, for lack of enablement or adequate written description. In GlaxoSmithKline LLC v. Banner Pharmacaps, Inc., 744 F. 3d. 725 (Fed. Cir. 2014), the Federal Circuit addressed the question of whether a claim directed to a new chemical entity and its solvates was appropriately supported, where the patent specification provided a general description of solvates.
The patent at issue, U.S. Patent No. 5,565,467 ("the '467 patent"), assigned to GlaxoSmithKline LLC ("GSK"), has claims directed to the chemical compound dutasteride or "a pharmaceutically acceptable solvate thereof". Id. at 727. GSK markets Avodart® and Jalyn™, which contain dutasteride, for the treatment of androgen responsive or mediated conditions, including benign prostatic hyperplasia, prostate cancer, acne, male pattern baldness and hirsutism. Id. When the defendants filed ANDAs seeking approval to market generic versions of Avodart® and Jalyn™, GSK responded by filing suit alleging infringement of the '467 patent. Id.
The defendants stipulated to infringement of the asserted patent claims, but challenged the validity of the '467 patent claims on several grounds, including anticipation, lack of utility, lack of enablement, and inadequacy of written description. Id. at 726. After a three-day bench trial, the trial court held that defendants had failed to prove that the claims of the '467 patent were invalid. Id.
Defendants presented a single issue on appeal: whether the patent's written description adequately supports the claims to "solvates" of dutasteride. Id. at 729. In relevant part, the specification provides that:
Those skilled in the art of organic chemistry will appreciate that many organic compounds can form complexes with solvents in which they are reacted or from which they are precipitated or crystallized. These complexes are known as "solvates." For example, a complex with water is known as a "hydrate." Solvates of [dutasteride] are within the scope of the invention.
It will also be appreciated by those skilled in organic chemistry that many organic compounds can exist in more than one crystalline form. For example, crystalline form may vary from solvate to solvate. Thus, all crystalline forms of [dutasteride] or the pharmaceutically acceptable solvates thereof are within the scope of the present invention.
Id. at 730 (quoting the '467 patent at 3:58-4:12). During the trial court proceeding, the parties agreed that solvates are molecules that either consist of solute molecules and solvent molecules or result from a solution of the solute and solvent molecules. Id. at 727.
The parties further agreed that solvate complexes may be crystalline, but disagreed as to whether, in the context of the '467 patent, solvates mean only crystalline complexes. Id. Accordingly, the defendants proposed a construction wherein a solvate is a complex of dutasteride and a solvent in which the arrangement is crystalline, resulting from crystallization out of a solution. Id. at 729. The district court did not accept this construction, and instead construed the claims more broadly to mean a complex of dutasteride and solvent, that may or may not be crystalline, resulting from any of three processes: reaction with a solvent, precipitation or crystallization out of a solution. Id.
The defendants nevertheless argued that under either construction the claims were invalid for lack of written description. According to the defendants, the portion of the specification relating to solvates (cited above) fails to adequately support claims directed to dutasteride solvates. Id. Defendants argued that the specification would have to independently describe a sufficiently wide range of crystalline, precipitated, and reacted solvates in order to support claims broadly directed to dutasteride solvates. GlaxoSmithKline LLC v. Banner Pharmacaps, Inc., No. 11-CV-046, 2013 WL 4082232 at *5 (D. Del. Aug. 9, 2013). The district court disagreed, finding that "[t]here is no reason why a person skilled in the art would not credit a patentee with possession of a solvate merely because the patentee did not disclose solvates formed by each solvation process." Id.
The Federal Circuit, without resolving the claim construction dispute, rejected the defendants' arguments because "[u]nder either the district court's claim construction or defendants' claim construction, the claim term 'solvate' refers to a molecular complex defined by structure and by the process of creating it, not by what the molecule does." Id. at 729. Thus, no matter which construction is adopted, the term "solvate" involves no performance property and hence raises no issue of insufficient structural, creation-process or other descriptions to support such a property. Id. at 729-30. Hence, the Court upheld the trial court's finding that term "solvate" is adequately described. Id.
The Court explained that the specification provides a sufficient written description of the "structure"' of the claimed dutasteride solvates. The patent specification defines the claimed "solvate" genus by two properties: "a solvate is a complex of dutasteride molecules and solvent molecules, with dutasteride being . . . 'the key structural component'," and "the structure is one that is created by an identified process-specifically, by dissolving dutasteride (the solute) in a solvent." Id. at 730. (Internal citations omitted). The Court determined that describing a complex of dutasteride and solvent molecules is an identification of "structural features commonly possessed by members of the genus that distinguish them from others." Id. The Court further noted that the written description in the specification matches the claim language, which also recites the structure of the compound and its process of creation. Id. The Court saw no reason to require any additional written description under these circumstances.
The Federal Circuit distinguished this case from the precedents the defendants cited by emphasizing the "structural" nature of the claim term "solvate." According to the Court, the disputed claim terms in the defendants' precedents were functional in nature, claiming a particular performance property. Such claims, the Court noted, have the "fundamental difficulty" of potentially claiming future inventions and may therefore exceed the scope of the written description. Id. at 731. "Solvate," on the other hand, "does not assert coverage of yet-unidentified ways of achieving a desired result; it does not 'attempt to preempt the future before it has arrived'." Id. (Internal citations omitted).
Thus, this case suggests that, while functional claim language may be helpful or even necessary in some circumstances, patent owners and practitioners should be cautious in using such language and be aware that functional claim terms may be more difficult to support. In contrast, claim language focusing on the structural aspects of a class of inventive compound may be more likely to withstand a validity challenge.
The case also serves to remind practitioners that the written description inquiry is highlyfactual and takes into account, among other factors, the knowledge of one of ordinary skill in the art. Here the Court emphasized the fact that the concept of solvation has been known for over 100 years and steroids—such as dutasteride—have been known to be prone to solvate formation since 1983. These facts supported the Court's conclusion that the general description of solvates in the patent specification was sufficient to support claims to dutasteride solvates.
Finally, this case suggests that, where the patentee uses consistent language in the claims and the specification, as GSK did here, the claims may be more likely to withstand a written description challenge. The careful practitioner should therefore remain mindful of maintaining this consistency, where possible, throughout prosecution as new claims or claim amendments are drafted.
Copyright © Finnegan, Henderson, Farabow, Garrett & Dunner, LLP. This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. This article is only the opinion of the authors and is not attributable to Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, or the firm's clients.
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