TAKEAWAY: As a practical matter, when construing a patent’s claims, the Federal Circuit may start further emphasizing the importance of intrinsic evidence, such as other patent claim terms, the specification, and the prosecution history, over extrinsic evidence, such as expert testimony.

In January, the Supreme Court clarified in Teva v. Sandoz that the Court of Appeals for the Federal Circuit owed more deference to district court findings about the meaning of patent claim terms, when it comes to “extrinsic” evidence, such as expert testimony, arising beyond the patent itself. Specifically, the Supreme Court held that the Federal Circuit should be reviewing such findings made by trial court judges for “clear error” rather than “de novo” (without deference). Early reactions to Teva included predictions that expert testimony and other extrinsic evidence would grow more influential. While that may eventually turn out to be the case, several recent cases from the Federal Circuit suggest that, as a practical matter, the Federal Circuit may for now start weighing intrinsic evidence more favorably than extrinsic evidence in order to retain de novo review of claim construction.

For example, in the recent decision in Enzo Biochem Inc. v. Applera Corp., the Federal Circuit reversed a district court’s construction notwithstanding the new deference it acknowledged owing under Teva. (No. 2014-1321, decided March 16, 2015.) In Enzo, the patent holder pointed to expert testimony (extrinsic evidence) as supporting the district court’s broader claim construction. The Federal Circuit disagreed, stating that “neither section of the ’767 patent specification cited by Enzo supports the inclusion of direct detection, even when extrinsic expert testimony is considered.” The Court reasoned that “[t]he district court concluded, based on expert testimony, that example 9 in the specification was an example of direct detection . . . Nevertheless, even if we were to consider the district court’s finding, which would be subject to review for clear error under Teva, this sole factual finding does not override our analysis of the totality of the specification.”

In Papst Licensing GMBH v. Fujifilm et al., the Federal Circuit overturned a district court’s construction of five different claim terms, all under de novo review, on the basis that the district court misconstrued intrinsic evidence applicable to all five claim terms, as a matter of law. (No. 2014-1110, decided February 2, 2015.) The Federal Circuit reasoned that the district court had received a tutorial from the parties’ experts, but had declined to admit expert testimony or rely on an expert declaration from Papst on any specific claim terms. Thus, the Court held that “the intrinsic evidence – the claims, the specification, and the prosecution history – provide the full record necessary for claims construction.”

Finally, in Fenner Investments, Ltd. v. Cellco Partnership, the Federal Circuit affirmed a district court’s claim construction upon de novo review, on the basis that the ultimate question involved only evidence intrinsic to the patent. (No. 2013-1640, decided February 12, 2015.) The district court had adopted Cellco’s proposed narrower construction of Fenner’s claimed “personal identification number” in its patent for wireless PCS phone systems. Fenner appealed the district court’s alleged importation of additional terms from the specification; its alleged over-reliance on estoppel created during prosecution; and its limitation of Fenner’s claim differentiation argument. On each issue, the Federal Circuit upheld the district court’s constructions applying de novo review of the district court’s evaluation of that intrinsic evidence.