Beware of Collateral Estoppel at the PTAB

When thinking about estoppel and the PTAB, the § 315(e) estoppels—relating to grounds a petitioner raised or reasonably could have raised—are likely the first to come to mind. However, other types of estoppel, such as collateral estoppel, also can apply to IPR proceedings.[1] The Federal Circuit recently issued a precedential opinion holding that collateral estoppel may apply to unpatentability findings for claims in different, related patents, when they share identical issue(s) of patentability and the other requirements for collateral estoppel are present.[2]

As background, Hammond Development International, Inc.’s U.S. Patent Nos. 9,264,483 and 10,270,816, each for a “[m]ethod and system for enabling a communication device to remotely execute an application,” issued in January 2016 and April 2019, respectively.[3] The patents are related and share the same specification. Hammond filed suit in the Western District of Texas, accusing Google, Inc. of infringing both patents in June 2019.[4]

Google filed a petition challenging claims of the ’483 patent in October of 2019[5]; and in April 2021, the PTAB held all challenged claims of the ’483 patent unpatentable as obvious.[6] In a parallel proceeding filed in November 2019, Google challenged all claims of the ’816 patent,[7] but did not assert the same grounds against all claims.[8] In June of 2021, the PTAB held all claims of the ’816 patent unpatentable as obvious except for independent claim 14 and its corresponding dependent claims 15-19.[9] The PTAB found that the prior art applied to independent claim 14 failed to suggest a “request for processing service.”[10] Notably, dependent claim 18 of the ’816 patent, which further defines the “request for processing service” of claim 14, and claim 18 of the ’483 patent (found unpatentable by the PTAB), both recite that the claimed request includes an instruction to present the user with voice or audio data.[11]

Google appealed the PTAB’s finding that claims 14-19 were not unpatentable to the Federal Circuit.[12] Google argued that collateral estoppel rendered claim 18 of the ’816 patent unpatentable based on the PTAB’s prior decision finding claim 18 of the ’483 patent unpatentable.[13] The parties agreed that if claim 18 was found unpatentable, then independent claim 14 also would be unpatentable.[14]

In its decision, the Federal Circuit reiterated that “[i]t is well established that collateral estoppel applies to IPR proceedings”[15] and that “patent claims need not be identical for collateral estoppel to apply.”[16] For a party to invoke collateral estoppel, four requirements must be satisfied: the issue must be identical to the one decided in the first action, the issue must have been actually litigated in the first action, the resolution of the issue must be essential to the final judgment in the first action, and the party against whom collateral estoppel is applied must have had a full and fair opportunity to litigate the issue in the first action.[17] To satisfy the first requirement of collateral estoppel for it to apply to patent claims, the issue of patentability must be the same.[18] Recognizing some differences in the claim language, the Federal Circuit nevertheless found that the “difference does not materially alter the question of patentability.”[19]

Here, the Federal Circuit held that the issue of patentability of claim 18 in the ’816 patent—a “request for processing a service”—was the same as that for claim 18 of the ’483 patent was already found to be obvious, so collateral estoppel rendered claim 18 of the ’816 patent unpatentable.[20] And, based on the parties’ agreement, the Federal Circuit similarly held claim 14 unpatentable.[21] Thus, the Federal Circuit reversed the decision as to claims 14 and 18, finding they were unpatentable based on collateral estoppel.[22] Because Google did not raise any collateral estoppel arguments as to claims 15-17 and 19, the Federal Circuit affirmed the PTAB’s decision that those claims were not unpatentable.[23]

Parties should consider Google v. Hammond when challenging or defending multiple patents in a patent family at the PTAB.

First, petitioners should consider whether claims in related patents found unpatentable in previous IPRs can be used against other claims. For example, in addition to providing grounds of unpatentability in a petition, a party challenging a claim related to and sharing the same issue of patentability as a claim already found unpatentable in a different IPR may be able to assert that claims challenged in their own petition are also unpatentable under the theory of collateral estoppel, assuming that all of the requirements of collateral estoppel are met.[24] This might occur, for example, where a patent owner serially asserts patents in a family against different defendants and some of the prior patent claims were found unpatentable by the PTAB.

Second, the PTAB’s findings of unpatentability in one patent may be applicable to other related patents. Parties should determine whether there is a favorable final written decision in an IPR and then evaluate whether collateral estoppel applies. For example, a situation might arise where there appears to be inconsistent findings by different panels, or even the same panel for different patents, regarding a common issue of patentability. Rather than appealing an unfavorable IPR decision to the Federal Circuit, if a petitioner (or other party) received a prior positive result from an IPR against a related patent, they should consider requesting rehearing at the PTAB based on Google v. Hammond. Rehearing at the PTAB could avoid the unnecessary time and expense of an appeal to the Federal Circuit. Parties should also consider the inverse: if a party receives an unfavorable final written decision when defending multiple related patents, they should consider appealing to prevent a final written decision in one case from negatively impacting the others.

This recent Federal Circuit opinion reinforces that collateral estoppel applies to PTAB proceedings and that parties on both sides of the “v” need to evaluate how and whether adverse PTAB decisions can affect their overall litigation strategy.