New Patent Claim Construction Review Standard

In early 2015, the U.S. Supreme Court changed the standard of review for patent claim construction with its decision in Teva Pharmaceuticals USA v. Sandoz Inc., 135 S. Ct. 831 (2015) (Teva I). Previously, the U.S. Court of Appeals for the Federal Circuit reviewed all claim construction rulings de novo—irrespective of whether they involved any factual findings—without giving any deference to the lower court's factual findings. In Teva I, the Supreme Court held that factual findings during claim construction such as findings related to extrinsic evidence must be given deference on appeal and should be reviewed for "clear error" instead.

In two recent cases, including the remand from Teva I, however, the Federal Circuit came to opposite conclusions when reviewing lower court decisions under the new clear error standard.