The U.S. Supreme Court or the U.S. Court of Appeals for the Federal Circuit – or both – will soon consider whether to modify the longstanding rule that patent claim construction rulings are subject to de novo review on appeal.

On March 14, 2013, Mirowski Family Ventures, LLC filed a petition for certiorari in the U.S. Supreme Court. Mirowski Family Ventures, LLC v. Medtronic, Inc. et al., Case No. 12-1116. The Mirowski cert petition posed the following question for review:

Where a district court has resolved conflicting expert testimony to decide a claim construction issue, should this decision be reviewed on appeal with no deference?

The following day, on March 15, the U.S. Court of Appeals for the Federal Circuit issued an en banc order, undertaking consideration by the full court of three broad questions concerning the appellate standard of review applicable to patent claim constructions. Lighting Ballast Control LLC v. Philips Electronics North America Corp., Case Nos. 2012-1014, -1015. The Federal Circuit has requested briefing from the parties and amici curiae on three issues:

  1. Should this court overrule Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998)?
  2. Should this court afford deference to any aspect of a district court’s claim construction?
  3. If so, which aspects should be afforded deference?”

The Mirowski and Lighting Ballast cases follow on the heels of the Supreme Court’s January 7, 2013 denial of certiorari in Retractable Technologies, Inc. v. Becton, Dickinson & Co., 133 S.Ct. 833 (2013). One of the key questions presented in Retractable Technologies’ March 20, 2012 petition for certiorari was:

Whether claim construction, including underlying factual issues that are integral to claim construction, is a purely legal question subject to de novo review on appeal.

Before ruling on the cert petition, the Supreme Court invited the Solicitor General to submit a brief expressing the views of the United States. Retractable Technologies, 133 S.Ct. 72. In his brief, the Solicitor General argued that certiorari should be denied. 2012 WL 5940288. The Solicitor General contended that the procedural posture of the Retractable Technologies case made it inappropriate as a vehicle for review of the Cybor-standard of review issue. Specifically, according to the Solicitor General, the district court had made no factual findings in rendering a claim construction that would have been entitled to greater deference on appeal. Id. at *20. Nonetheless, the Solicitor General argued, “[ I ]t is clear … that some claim-construction decisions will depend on a district court’s resolution of subsidiary factual questions. The Federal Circuit’s decision in Cybor does not identify any reason that such factual findings should not be given the deference ordinarily required by Federal Rule of Civil Procedure 52(a) …” Id. at *21. Shortly thereafter, the Supreme Court denied certiorari, but commentators and court-watchers have voiced their expectations that another case would soon be offered up as a more suitable vehicle for revisiting Cybor.

The Cybor case, the apparent target of each of these three appeals, was decided in 1998, not long after the Supreme Court’s landmark ruling in Markman v. Westview Instruments, 517 U.S. 370 (1996). The Markman case requires courts, not juries, to construe patent claims. Two years after Markman, the Federal Circuit ruled that, because claim construction presents pure issues of law, claim constructions are to be reviewed de novo, without deference to the trial court’s interpretation. Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998).

The de novo standard of review for patent claim constructions, established in Cybor, has long been criticized by commentators and patent litigators because the trial court’s claim constrictions often form a significant basis for how the issues are framed for trial. A changed claim construction on appeal can significantly alter the merits of the case, resulting in significant additional expense in retrial of cases on remand following appellate modification of claim construction rulings.