De Novo Review of Patent Claim Construction

In October 2014, the U.S. Supreme Court heard argument in Teva Pharmaceuticals USA v. Sandoz, (No.13-854) (Oct. 15, 2014), a case that should finally resolve the Federal Circuit’s multi-decade debate concerning the appellate standard of review for claim construction. Sixteen years ago, in Cybor v. FAS Technologies, 138 F.3d 1448 (Fed. Cir. 1998) (en banc), the Federal Circuit held that the district court’s claim construction should be given no deference. But after Cybor, Federal Circuit judges remained deeply divided on this issue and in 2013 re-visited it in Lighting Ballast Control v. Philips Electronics, Nos. 2012-1014, 2014 WL 667449 (Fed. Cir. Feb. 21, 2014). To the surprise of some, the Federal Circuit maintained its de novo review of claim construction. But shortly thereafter, on March 31, 2014, the Supreme Court decided it was time for it to address this issue itself. Teva Pharmaceuticals USA. v. Sandoz, (No.13-854) 2014 WL 199529 (March 31, 2014). Now the question is whether the court will overrule Cybor, a question that is important to both practitioners and district court judges.

Evolution of the Standard of Review

Since its inception in 1982, the Federal Circuit grappled with whether claim construction was a purely legal issue, or a mixed issue of law and fact. On one side, cases held that claim construction was a “legal or factual, or mixed issue,” applying deference to the district court’s factual conclusions. McGill v. John Zink, 736 F.2d 66 (Fed. Cir. 1984). Along an opposite line of cases, claim construction was interpreted as strictly a matter of law, subject to de novo review. SSIH Equip. S.A. v. United States Int’l Trade Comm’n, 718 F.2d 365, 376 (Fed. Cir. 1983).