In M2M Sols. LLC v. Sierra Wireless Am. Inc., No. 1:14-cv-01102-RGA, ECF No. 213 (D. Del. Mar. 31, 2021) (Andrews), the court ruled that collateral estoppel should apply to surviving claims that are not materially different than claims in the same patent that were ruled unpatentable in a prior IPR, even though the PTAB’s evidentiary and claim construction standards differ from those applied in court.

M2M filed a patent infringement action alleging Sierra infringed U.S. Patent No. 8,648,717 (“the ’717 patent”). The ’717 patent claims a programmable communicator device that can control data transmitted between at least two devices.

In two prior IPRs, the PTAB determined that most claims of the ’717 patent were unpatentable, but did not rule on claims 25-28 and 30. The PTAB’s final written decisions were prior to its adoption of the “plain and ordinary meaning” standard, and therefore applied the “broadest reasonable interpretation” standard for claim construction .

In the subsequent district court proceedings, Sierra argued on summary judgment that collateral estoppel should apply because there were no material differences between claims 25-27 of the ’717 patent and the unpatentable claims. Sierra relied on Federal Circuit precedent holding that collateral estoppel may extend to unadjudicated patent claims when there are no material differences between the unadjudicated and adjudicated claims. 

In response, M2M argued that there was no identity of issues because different burdens of proof apply in each tribunal. M2M further argued that a dispute between the parties’ experts regarding the plain and ordinary meaning of a particular term raised a genuine issue of material fact sufficient to defeat summary judgment. M2M did not dispute Sierra’s assertion that the claims at issue were not materially different from those invalidated by the PTAB and that M2M did not challenge any remaining prong of the issue preclusion analysis beyond raising the differing claim construction standard.

The district court noted that prior Fed. Cir. decisions had found that “differing burdens of proof will not prevent the application of collateral estoppel to PTAB decisions that meet all other requirements.” The judge additionally noted that it did not believe that M2M, through testimony by its expert, had raised an actual dispute of material fact as to the plain and ordinary meaning of any claim term. The judge therefore granted issue preclusive effect to the PTAB’s invalidity decision despite differences in the claim construction standards that would naturally arise upon review by the district court.

This case shows that collateral estoppel from and IPR can apply if it can be shown that claims are not materially different, even if a different claim construction is used at the PTAB.