Last month, the Federal Circuit’s holding in Google LLC v. Hammond Dev. Int’l, Inc. illustrated the importance of raising a collateral estoppel argument when the opportunity arises. In Google LLC v. Hammond Dev. Int’l, Inc., the Court decided the patentability of claims directed to subject matter that was previously held unpatentable following an IPR of a different patent.
Google challenged two of Hammond Development International’s patents, U.S. Patent No. 10,270,816 (“the ’816 patent”) and 9,264,483 (“the ’483 patent”) in IPR proceedings. The ’816 patent and the ’483 patent share a specification and relate to a “communication system that allows a communication device to remotely execute one or more applications.” The Patent Trial and Appeal Board (“the Board”) issued its first decision in April of 2021 invalidating all challenged claims of the ’483 patent as being obvious based on a prior art combination. With respect to the ’816 patent, the Board later held Google failed to show claim 14 and its corresponding dependent claims 15-19 were unpatentable.
On appeal, Google asserted claim 18 was invalid based on collateral estoppel in view of the holding in the ’483 patent IPR proceeding. Google asserted claim 18 was invalid because the Board found a similar claim unpatentable in the ’483 patent IPR proceeding. However, Google did not assert estoppel for the remaining claims. Instead, Google asserted independent claim 14 was invalid because its dependent claim, claim 18, was invalid and claims 15-17 and 19 were invalid because the Board found similar claims in the ’483 patent unpatentable.
The Federal Circuit ultimately issued three rulings related to collateral estoppel. First, collateral estoppel was available to Google because the final written decision of the ’483 patent proceeding was issued after Google filed the IPR petition for the ’816 patent. Second, claim 18 was invalid under collateral estoppel because issues of patentability were identical in the two IPRs. Finally, independent claim 14 was invalid because the parties agreed that if claim 18 was unpatentable, then so was claim 14.
The Federal Circuit, however, affirmed the Board’s finding of claims 15-17 and 19 as patentable. The Court was not convinced by Google’s arguments where they pointed to similar claim language in the other IPR proceeding. But yet the Court went out of their way to state “Google failed to raise any collateral estoppel arguments with respect to these claims.” Without explicitly stating so, the Federal Circuit may be signaling the remaining dependent claims were invalid if only Google asserted a collateral estoppel argument.
Defendants should consider Google LLC v. Hammond Dev. Int’l, Inc. when challenging multiple patents from the same family. An initial IPR procedure for a single patent may help invalidate claims that are substantially similar from other members of the family. While Google may have excluded such arguments for strategic purposes, the Federal Circuit is certainly inviting future litigants to bring these types of collateral estoppel arguments.
 54 F.4th 1377 (Fed. Cir. 2022).
 Id. at 1379.
 Google LLC v. Hammond Dev. Int’l, Inc., No. 2021-2218, 2021 WL 5936923, at *33 (Fed. Cir.).
 Id. at 35.
 Id. at 39-41.
 Claim 18 of the ’816 patent recited “a first one of the plurality of application servers configured to execute a first application” and “a second one of the plurality of application servers.” Claim 18 of the ‘483 patent recited “one or more application servers” and requires “the at least one application server.” The Court concluded the scope of the claims were materially identical.
 Google LLC v. Hammond Dev. Int’l, Inc., 54 F.4th 1377, 1382 (Fed. Cir. 2022).