Procedurally, the district court in this case held that the term “molecular weight” was sufficiently definite largely based on the court’s credibility determination regarding the expert testimony presented. On appeal, the Federal Circuit reversed without finding that the district court’s factual finding of expert credibility was made in clear error. Thus, under the new standard, the Supreme Court vacated and remanded the case.
Importantly, the Supreme Court noted that although factual underpinnings are to be given deference, the Federal Circuit may still review the district court’s ultimate construction de novo. And in situations where the district court only considers evidence intrinsic to the patent, i.e., specification, claims, and prosecution history, the decision will always be reviewed de novo. Accordingly, it is unclear what the practical impact the decision will have on cases moving forward.
Teva Pharm. USA, Inc. v. Sandoz, Inc., No. 13854, 2015 WL 232131 (U.S. Jan. 20, 2015).