In the Federal Circuit’s recent decision of CUPP Computing AS v. Trend Micro Inc., the Court made the precedential holding that the Patent Trial and Appeal Board (“the Board”) is not bound by a party’s disclaimer in the very IPR proceeding in which it is made, just as a disclaimer in a district court proceeding would not bind the district court in the same proceeding. The Court’s decision cements its earlier nonprecedential opinion in VirnetX, in which the Court held that the Board “is not required to accept a patent owner’s arguments as disclaimer when deciding the merits of those arguments.”
The Court’s decision is rooted in the principle of keeping patent monopolies with their “legitimate scope.” The Court reasoned that permitting “patentees to modify their claims by disclaimer would…effectively allow retrospective amendment in the IPR process” and create an opportunity for patentees to “avoid the public-protecting amendment process that Congress prescribed.”
The Court also provided a brief summarization of the precedential nature of disclaimers. The Court restated that the “doctrine of prosecution disclaimer precludes patentees from recapturing through claim interpretation specific meanings disclaimed during prosecution.” Further, a ““patentee will only be bound to a ‘disavowal that was both clear and unmistakable.” To the contrary, if “the alleged disavowal is ambiguous, or even amendable to multiple reasonable interpretations,” the Court has declined to find prosecution disclaimer.
In sum, the Federal Circuit’s holding in CUPP (1) reaffirms the limited role of a disclaimer within the proceeding in which is it made and (2) restates the potential that a disclaimer binds the patentee to a narrower claim interpretation in a subsequent proceeding.
 See CUPP Computing AS v. Trend Micro Inc., No. 2020-2262, 2022 WL 16954357, at *5 (Fed. Cir. Nov. 16, 2022)
 VirnetX Inc. v. Mangrove Partners Master Fund, Ltd., 778 F. App’x 897, 910 (Fed. Cir. 2019))
 CUPP Computing AS, 2022 WL 16954357, at *5.
 Mass Inst. of Tech. v. Shire Pharms., Inc., 839 F.3d 1111, 1119 (Fed. Cir. 2016)
 CUPP Computing, 778 F.App’x at 5* (quoting Mass Inst. of Tech. v. Shire Pharms., Inc., 839 F.3d 1111, 1119 (Fed. Cir. 2016))
 Avid Tech., Inc. v. Harmonic, Inc., 812 F.3d 1040, 1045 (Fed. Cir. 2016).