The doctrine of prosecution disclaimer prevents patent owners from recapturing specific meanings of claim terms that were disclaimed during prosecution. See, e.g., Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1323 (Fed. Cir. 2003). For the doctrine to apply, the disavowing actions or statements by the patent owner must be both clear and unmistakable. Id. at 1325-26. The purpose of this doctrine is to ensure that claims are not construed one way by the patent owner to obtain their allowance before the U.S. Patent and Trademark Office, and in a different way against accused infringers. Southwall Techs., Inc. v. Cardinal IG Co., 54 F.3d 1570, 1576 (Fed. Cir. 1995). In a case of first impression, the Federal Circuit was asked if the doctrine of prosecution disclaimer applies to statements made by a patent owner in an inter partes review (IPR), including comments in the patent owner’s preliminary response.
Aylus Networks, Inc. sued Apple Inc. for infringement of U.S. Patent No. RE 44,412 (the `412 patent). Aylus Networks, Inc. v. Apple Inc., No. 2016-1599, slip op. at 6 (Fed. Cir. May 11, 2017). Apple filed two separate IPR petitions with the Patent Trial and Appeal Board (PTAB) to challenge claims of the patent. The PTAB denied institution for claims 2, 4, 21, and 23, but instituted review against the other challenged claims. Id. In the district court litigation, Aylus voluntarily dismissed infringement contentions for all claims of the `412 patent except for claims 2 and 21 for which the PTAB denied institution. Apple filed for summary judgment of non-infringement of claims 2 and 21 which was granted by the district court. Id. In its order, the district court construed a limitation of the claims in a manner that relied on statements made by Aylus in its preliminary response in the IPRs, and explained that Aylus’s statements in the IPR were “akin to prosecution disclaimer.” Id. at 8.
When appealing the district court’s grant of summary judgment, Aylus’s arguments centered on whether its statements in a preliminary patent owner response could be considered prosecution disclaimer. The Federal Circuit observed that the doctrine of prosecution disclaimer has been applied to other post-issuance proceedings before the Patent Office including reissue and reexamination proceedings. Id. at 10 (citing Standard Oil, 774 F.2d at 452); see also In re Katz Interactive Call Processing Patent Litig., 639 F.3d 1303, 1324-25 (Fed. Cir. 2011) (finding no error in district court’s claim construction based on arguments made during reexamination). To distinguish from this precedent, Aylus argued that IPR proceedings are adjudicative proceedings that are different from administrative proceedings like reissue or reexamination proceedings. Aylus Networks, slip op. at 11. The Federal Circuit disagreed and relied on the Supreme Court’s discussion in Cuozzo directed to how IPRs were created to serve as a means of reexamining an earlier agency decision. Id. at 11-12 (citing Cuozzo Speed Techs. LLC v. Lee, 136 S. Ct. 2131, 2143 (explaining that in some “significant respects, inter partes review is less like a judicial proceeding and more like a specialized agency proceeding.”).
Aylus also argued that the preliminary patent owner response was filed prior to institution and was therefore not part of the IPR proceeding. The Federal Circuit explained that even though patent owner preliminary responses are filed pre-institution, preliminary responses are official, publicly available papers filed with the Patent Office that represent the patent owner’s position regarding claim terms and their scope, and that these statements were made to avoid prior art for purposes of maintaining patentability. Id. at 13-14.
In view of existing precedent holding that patent owner statements in post-issuance proceedings could constitute prosecution disclaimer, the Federal Circuit explicitly extended the prosecution disclaimer doctrine to include IPR proceedings. Id. at 10. The Federal Circuit then considered if Aylus’s statements amounted to a clear and unmistakable surrender of claim scope needed to qualify as prosecution disclaimer.
Aylus argued that the statements made in its preliminary response were not clear and unmistakable because the statements were allegedly subject to more than one reasonable interpretation. Id. at 14. The Federal Circuit rejected this argument. Aylus, in both the patent owner preliminary response and in the patent owner response, made statements as to the meaning of the claim terms. Id. at 15-16. The PTAB relied on these representations by Aylus when deciding not to institute proceedings against claims 2 and 21 of the `412 patent. Id. at 14-16. Most importantly, the Federal Circuit found the alternative interpretation proffered by Aylus was not reasonable because it was inconsistent with the claims of the `412 patent. Id. at 16-18. Indeed, the Federal Circuit found the claim language and the specification of the `412 patent supported the district court’s construction. Id. With these considerations in mind, the Federal Circuit found Aylus’s statements to qualify as prosecution disclaimer and affirmed the district court’s grant of summary judgment of non-infringement to Apple.
The Federal Circuit has now made clear that the doctrine of prosecution disclaimer applies to patent owner statements made during IPR proceedings, even when the statements are made in a patent owner preliminary response. Patent owners should therefore be careful to avoid unnecessarily creating prosecution disclaimer when preparing responses in IPRs, particularly when district court litigation is copending.