The Federal Circuit issued an opinion on Monday in GlaxoSmithKline LLC v. Banner Pharmacaps, Inc. illustrating how difficult it can be to overturn a district court determination based on a question of fact, at least when the question involves a chemical compound defined by structural properties supported by a description of how such a compound can be made.

The lawsuit involved the drug dutasteride, sold by GSK under the brand names Avodart^®and Jalyn™ for the treatment of "androgen responsive diseases," and GSK brought suit under the provisions of 35 U.S.C. § 271(e)(2) following ANDA filings by defendants Banner Pharmacaps, Inc., Impax Laboratories, Inc., Mylan, Inc., Mylan Pharmaceuticals, Inc., and Watson Laboratories, Inc.  The claim at issue, from Orange Book listed U.S. Patent No. 5,565,467, recited in its entirety "17ß-N-(2,5-bis (trifluoromethyl)) phenylcarbamoyl-4-aza-5a-androst-1-en-3-one or a pharmaceutically acceptable solvate thereof."  The District Court rendered judgment against all defendants, who had stipulated infringement, ruling that defendants failed to establish by clear and convincing evidence that this claim was invalid for "anticipation, lack of utility, lack of enablement, and inadequacy of the written description."

On appeal, Defendants challenged the District Court's claim construction with regard to the scope and meaning of the term "a pharmaceutically acceptable solvate thereof" as that construction was relevant to their written description defense.  The Federal Circuit affirmed, in an opinion by Judge Taranto joined by Judges O'Malley and Wallach.  Curiously, the opinion did not resolve defendants' challenge to the District Court's interpretation of the term "solvate."  Instead, the Court set forth its understanding of the meaning of the term, specifically that a solvate "is something that originates in a 'solution,' which is a mixture of two substances: a 'solute' dissolved in a 'solvent.'"  This definition is consistent with the positions of both parties, according to the opinion, and in addition that the parties agree that a solvate can be in the form of a crystal.  The disagreement between the parties concerned whether a solvate must be in a crystalline form (defendants' position) or not (GSK's position.  While there was "considerable extrinsic evidence" supporting defendants' position, the District Court relied upon the express teachings in the '467 patent specification in deciding that the claimed solvates were not limited to crystalline forms, wherein a solvate was defined as:

A complex formed by dutasteride with a solvent in which dutasteride is reacted or from which it is precipitated or crystallized.

Solvates according to the specification can be produced "by a reaction of dutasteride with a solvent; by precipitation of a complex from a solution of dutasteride and a solvent; by crystallization of a complex from a solution of dutasteride and a solvent," without a requirement that the solvate produced by any of these methods be in the crystalline form.

Adequacy of a specification's written description is a question of fact (reviewed for clear error by the Federal Circuit), and accordingly the Federal Circuit's opinion set forth the District Court's factual findings in support of its decision that defendants had failed to establish invalidity on these grounds.  Specifically, the opinion set forth the District Court's findings that methods for producing solvates of steroid compounds (like dutasteride) were well known in the art and that the "universe of solvents thought to be pharmaceutically acceptable was well-known and relatively small."  While it was impossible to predict whether any particular solvate produced according to these well-known methods would be pharmaceutically acceptable, the District Court found that methods for determining pharmaceutical acceptability were also well known in the art.  Regarding the adequacy of defendants' challenge, the District Court found that:

There 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, i.e., reaction, precipitation, crystallization.

In the Federal Circuit's opinion, Judge Taranto noted the limited scope of the issue on appeal, and that defendants had not properly included a challenge on whether the specification adequately described the range of pharmaceutically acceptable solvates encompassed by the '467 patent claim.  Under either plaintiff's or defendants' claim construction, the Court found that the term "solvate" was one "defined by structure and by the process of creating it" rather than by its function.  The Federal Circuit recognized that the District Court construed the term to comprise "any complex of dutasteride and solvent" that resulted from any of the described methods:

In either event [plaintiff's or defendants' claim interpretation], the written description, which presents materially the same interpretive choice, describes the same class by identifying a particular structure obtained by particular processes.  No matter which construction is adopted, the term "solvate" involves no performance property (the claimed compound need not perform an identified function or produce an identified result) and hence raises no issue of insufficient structural, creation-process, or other descriptions to support such a property.

Turning to the specification, the opinion asserts that the language defines the genus of pharmaceutically acceptable solvates as "a complex of dutasteride molecules and solvent molecules, with dutasteride being, as the district court found, 'the key structural component'" and "one that is created by an identified process -- specifically, by dissolving dutasteride (the solute) in a solvent."  Noting the parties dispute the meaning of these teachings from the specification, the opinion states that "under each side's construction and reading of the specification, the description matches the claim, and regardless of which side is right, the description remains entirely based on structure of the compound and its process of creation."  Citing Ariad v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc), Regents of the Univ. of California v. Eli Lilly & Co., 119 F.3d 1559, 1568 (Fed. Cir. 1997), and Boston Scientific Corp. v. Johnson & Johnson, 647 F.3d 1353, 1366-67 (Fed. Cir. 2011), the opinion notes that this structural description is consistent with the Court's written description jurisprudence.  Here, the Court finds that claim scope is "no broader" than what is described in the specification, "whether [that scope] is narrow or broad, as the parties dispute," and that the term "solvate" is structural nor functional in nature (a "critical" distinction according to the opinion, albeit a sentiment followed by statements regarding the adequacy of the description to "make and use" the invention that seemingly introduces questions of enablement into the written description analysis).  The Court draws this "structural vs. functional" difference in distinguishing case law cited by defendants in support of their position, because "[h]ere, []under any of the parties' preferred claim constructions, 'solvates' of dutasteride are not distinguished by a particular performance property."  Accordingly, the panel could find "no basis" for overturning the District Court's finding that the claims were adequately described.

GlaxoSmithKline LLC v. Banner Pharmacaps, Inc. (Fed. Cir. 2014)
Panel: Circuit Judges O'Malley, Wallach, and Taranto
Opinion by Circuit Judge Taranto.