For over 15 years, the Federal Circuit has applied a de novo standard of review when reviewing claim constructions determined by a district court. Many practitioners argue that the Federal Circuit has applied the wrong standard of review. In support of their position, they point to Rule 52(a) which provides that in matters tried to a district court, the court’s “[f]indings of fact … must not be set aside unless clearly erroneous.”
In February 2014, a Standing Committee on Rules of Practice and Procedure of the United States published proposed amendments to the Federal Rules of Civil Procedures. Although not among these proposals, Rule 52(a) has received much concern in the patent law community.
Claim Construction Debate
Resolving a long dispute over who should determine the meaning of patent claims, the Supreme Court in Markman v. Westview Instruments held judges were better suited than the jury in construing the meaning of patent terms. Two years later, addressing the issue of appellate review of claim constructions, the Federal Circuit in Cybor Corp. v FAS Techs, Inc., held “as a purely legal question, we review claim construction de novo on appeal including any allegedly fact-based questions relating to claim construction.” The debate continued with arguments that Markman did not mean that a district court’s factual findings on claim construction should be reviewed de novo on appeal.
Rule 52(a) Debate
In February 2014, sitting en banc in Lighting Ballast v. Philips Electronics, the Federal Circuit reaffirmed the Cybor de novo appellate review of claim construction. Dissenting, Judge O’Malley stated “when a district court makes fact findings needed to resolve claim construction disputes, Rule 52(a) requires us to defer to those findings unless they are clearly erroneous.”
Because claim construction decides what a patent covers and presumably the most important ruling in a patent case, Cybor supporters argue a de novo standard of review is necessary. Seeking faster resolution, opponents to a Cybor de novo standard prefer deference to the district court’s factual findings in its claim construction. Others argue a deference standard of view would promote forum shopping – which the Federal Circuit was created to prevent.
Until recently the Supreme Court has declined to address appellate review of claim construction. Granting certiorari to Teva v. Sandoz (No. 13-854), the Supreme Court recently agreed to weigh in on this debate. The question presented is “whether a district court’s factual finding in support of its construction of a patent claim term may be reviewed de novo or only for clear error, as Rule 52(a) requires.”
Briefing for Teva begins May 2014 with oral arguments possibly in October 2014; however, a decision may not come until June 2015. Meanwhile, the Federal Circuit maintains non-deference to the district court for claim construction rulings.