The U.S. Supreme Court has issued a case opinion that will generally make a district court's interpretation of patent-claim terms more difficult to reverse on appeal and, thus, will raise the importance of which particular District judge presides over a patent case. In other words, the case will likely raise the importance of venue determinations such as a patent-infringement plaintiff's choice where to file a patent-infringement suit and determinations on defendants' motions to transfer.

In Teva Pharms. USA, Inc. v. Sandoz, Inc., No. 13-854, 2015 U.S. LEXIS 628 (January 20, 2015) the Supreme Court held that while a district judge's construction of the meaning of a patent claim's term is a matter of law that is reviewed de novo (i.e., without deference) on appeal, factual determinations underlying the construction are instead reviewed for clear error (a more difficult standard for obtaining a different result on appeal). The Court explained that when a district judge construes a patent-claim term using only intrinsic evidence (the patent claims, specification, and prosecution history), the judge's determination is purely a determination of law that will be reviewed on appeal by the de novo standard. However, when a district judge also considers extrinsic evidence (anything other than the patent claims, specification, and prosecution history; for example, expert testimony) to determine underlying factual disputes—such as how a person of ordinary skill in the art would understand a chart presented in the patent—that factual finding will be reviewed for clear error.

The Teva opinion increases the importance of the determination of which particular district judge presides over a patent case. The meaning of patent-claim terms are of paramount importance in a patent-infringement suit (including potentially affecting a patent claim's validity). and Teva makes a district judge's claim construction potentially more difficult to reverse on appeal. For in-stance, in Teva, the district judge—based on the judge's claim construction—held that the patent claim was sufficiently definite and the Federal Circuit Court of Appeal—based in part on disagreement with the district judge's underlying factual finding—held the patent claim was indefinite. Because the Supreme Court instructed that the district judge's factual finding was to be reviewed de novo, the Court reversed the Federal Circuit's ruling.