IPR Fact Findings Don’t Bind District Courts (What about IPR Legal Conclusions?)

by Dennis Crouch

Issue preclusion (also called collateral estoppel) prevents parties from relitigating issues already decided in prior proceedings. To apply issue preclusion, courts generally require: (1) the issue was actually litigated and decided in the prior proceeding; (2) the determination was essential to the judgment; (3) the party against whom preclusion is asserted had a full and fair opportunity to litigate; and (4) the party against whom preclusion is asserted was a party (or in privity) in the prior proceeding. Issue preclusion can sometimes dispose of an entire case, but it can also apply more narrowly -- operating to prevent relitigation of any individual issue of law or fact that was already resolved in a prior proceeding.

Issue preclusion has the potential of arising often in patent cases -- especially because most patent cases these days involve two different proceedings (1) the IPR; followed by (2) the district court litigation.

A key way this comes up is when an IPR cancels several claims, but then the patentee subsequently amends the lawsuit to assert other claims that are similar but not identical to those cancelled. An example here might be that the cancelled claim involved elements A, B, C, and D; and the newly asserted claim covers A, B, C, and Δ.  The accused infringer would hope to invoke issue preclusion, arguing that it is a settled fact that the prior art teach A, B, C, and D, leaving only the question of whether the Δ modification is obvious.

But, the Federal Circuit has generally prohibited this approach because in IPRs facts are are decided under the lower preponderance-of-the-evidence standard while invalidating a patent in court requires the higher clear-and-convincing standard for invalidity. In issue preclusion lingo, this means that the IPR decision is not the same issue being decided in litigation.   The court has addressed this issue in some prior cases, including ParkerVision, Inc. v. Qualcomm Inc., 116 F.4th 1345 (Fed. Cir. 2024), and Kroy IP Holdings, LLC v. Groupon, Inc., 127 F.4th 1376 (Fed. Cir. 2025).

The court's newest decision makes clear the broad scope of the rule: