Last week, the U.S. Court of Appeals for the Federal Circuit issued an opinion in Actelion Pharmaceuticals Ltd. v. Mylan Pharmaceuticals Inc., 22-1889 (Nov. 6, 2023), vacating and remanding the district court’s judgment of patent infringement.
Actelion owns two patents for epoprostenol formulations, which are used to treat cardiovascular disease. The patents describe epoprostenol solutions with a high pH having improved stability compared to an earlier product called Flolan. At the center of the case was the district court’s construction of the claim term “a pH of 13 or higher”.
Actelion and Mylan both argued the claim term should be given its “plain and ordinary meaning”. Actelion argued that plain and ordinary meaning includes numbers as low as 12.5 because those numbers round to 13. According to Actelion, if a “pH of 13 or higher” was not meant to include lower numbers that round to 13, it would have been written as “13.0.” Mylan argued that the plain and ordinary meaning is limited to pHs of 13 or higher and does not include lower numbers that round to 13. Actelion cited to numerous textbooks, and both parties made arguments that the textbooks supported their respective positions. The district court did not address the extrinsic evidence, and instead decided the issue in favor of Actelion based on intrinsic evidence alone. The district court explained that “under its conventional significant figure meaning, the term ‘a pH of 13’ would ordinarily encompass those values that round up or down to 13, 12.5 to 13.4” and that the specification did not indicate an intention by Actelion to import any higher degree of precision. Under that construction of the term, the parties stipulated to judgment of infringement and Mylan appealed.
The Federal Circuit reviewed the construction of the term “pH of 13 or higher” de novo. The Court first noted that the absence of the modifier “about” was insufficient to resolve the dispute. The Court next determined that the specifications and prosecution histories of the Actelion patents did not resolve the dispute either. Rather, the Court concluded, consideration of extrinsic evidence was necessary and “the district court should have considered, at a minimum, the textbook excerpts offered and addressed by the parties.” Accordingly, the Court vacated and remanded to the district court with instructions to consider the extrinsic evidence and its impact on the proper construction of the disputed claim term.