Last week, the U.S. Court of Appeals for the Federal Circuit issued an opinion in Sage Products, LLC v. Stewart, No. 2023-1603 (Apr. 15, 2025), affirming the final written decisions of the Patent Trial and Appeal Board invalidating the challenged claims of U.S. Patent Nos. 10,398,642 and 10,688,067.
The patents-in-suit relate to “sterilized” chlorhexidine antiseptics. As construed by the Board, an antiseptic is sterilized if it has been subjected to a suitable sterilization process such that sterility can be validated. The Board invalidated the challenged claims in view of the ChloraPrep Public Assessment Report (“PAR”), which is a publication from the UK’s regulatory equivalent to the FDA evaluating ChloraPrep. The PAR describes ChloraPrep as “sterile” but does not identify the processes by which ChloraPrep is “sterilized.” The Board referred to UK industry standards for sterility to determine the meaning of “sterile” within the PAR.
Sage argued that when the PAR was written, the pharmaceutical industry mistakenly believed that antiseptics such as ChloraPrep were properly sterilized and discovered sterilization issues prior to the invention. Specifically, the US version of ChloraPrep was no longer considered sterile. Sage argued that it was improper for the Board to consider the UK sterility regulations to determine what sterilization techniques would have been used in the PAR because (1) a POSA would not have been familiar with the UK industry standards and (2) the UK industry standards were not included as part of the ground asserted in the petition for inter partes review.
The Federal Circuit affirmed. First, the Court credited the Board’s factual findings that the UK version of ChloraPrep was subject to suitable sterilization processes within the meaning of the patents. The Court also credited the Board’s factual findings that a POSA would have been familiar with the regulatory regimes for products in their industry and the differences in regulation across different countries. Finally, the Court held that it was proper for the Board to determine what a POSA would understand “sterile” to mean in the PAR by reference to extrinsic evidence not presented in the grounds of the petition.
