Patent Owners Beware of Prior Adjudication Involving Related PatentsDecember 22, 2022

When patent claims are construed and interpreted in an adjudicative proceeding, such as patent infringement litigation in federal court or in an adjudicative proceeding before the Patent Trial and Appeal Board (“PTAB”), a preclusive effect can arise which can affect the validity of claims of related patents.

For example, on December 8, 2022, in Google LLC v. Hammond Development International, Inc., (“Google v. Hammond”) the Court of Appeals for the Federal Circuit (“Federal Circuit”) held claims 14 and 18 of U.S. Patent No. 10,270,816 (“the ‘816 patent”) to be unpatentable in light of previously adjudicated claims in a related patent. Google v. Hammond was an appeal filed by Google LLC (“Google”) following an inter partes review (“IPR”) proceeding in which the PTAB concluded that Google failed to show claims 14-19 of the ‘816 patent to be unpatentable.

On appeal, the Federal Circuit applied the doctrine of collateral estoppel noting that the same issue of patentability had been previously adjudicated. In a previous IPR proceeding, Google challenged claims of U.S. Patent No. 9,264,483 (“the ‘483 patent”), which is related to the ‘816 patent and is also owned by Hammond Development International, Inc. (“Hammond”). In that proceeding, the PTAB concluded that the challenged claims of the ‘483 were unpatentable, and Hammond failed to appeal the PTAB’s decision.

In Google v. Hammond, the Federal Circuit provided the elements necessary to show collateral estoppel: “(1) the issue is identical to one decided in the first action; (2) the issue was actually litigated in the first action; (3) resolution of the issue was essential to a final judgment in the first action; and (4) [the party against whom collateral estoppel is being asserted] had a full and fair opportunity to litigate the issue in the first action.” The court indicated that the only element in dispute was the first one: whether the issue in the IPR proceeding regarding the ‘483 patent was the same as the issue in the IPR proceeding regarding the ‘816 patent. The Federal Circuit concluded that an identical issue of patentability was involved in both adjudications. Therefore, the court concluded that collateral estoppel rendered claim 18 of the ‘816 patent unpatentable because the issue of patentability regarding claim 18 was identical to that of a challenged claim of the ’483 patent, which was previously found to be unpatentable by the PTAB. Claim 14 of the ‘816 patent was also held to be unpatentable because it was agreed by the parties that if claim 18 was unpatentable, claim 14 was also unpatentable.

The Federal Circuit’s decision in Google v. Hammond serves as a reminder to patent owners that patent claims adjudicated in previous proceedings can have a preclusive effect on subsequent adjudicatory proceedings involving related patents. Additionally, in the Federal Circuit’s decision, the court noted that “patent claims need not be identical for collateral estoppel to apply … [r]ather, collateral estoppel requires that the issues of patentability be identical.” Thus, based on the foregoing, it is important for patent owners to remember that previous adjudications regarding patent claims can have ongoing preclusive effects for related patents.

Joseph M. Hallman is a Patent Attorney in the Mechanical and Electrical Patent Practice Group at McKee, Voorhees & Sease, PLC. For additional information please visit or contact Joseph directly via email at

← Return to Filewrapper

Stay in Touch

Receive the latest news and updates from us and our attorneys.

Sign Up