Full Estoppel Required For A Stay When Third Party Files IPR

Patent litigants or other "real parties in interest" are estopped from asserting invalidity challenges in federal court "on any ground that the petitioner raised or reasonably could have raised during the inter partes review [IPR]." The estoppel is more nuanced when a third party files the IPR, such as when the defendant and third party are both alleged infringers of the challenged patent. There, for estoppel to apply, the defendant typically agrees to be bound by the same estoppel that bound the third party who filed the IPR in the first place.

In the case of Intellectual Ventures II LLC v. Kemper Corp. et al., Case No. 6:16-cv-0081 (E.D. Texas Nov. 7, 2016), this issue was presented to Judge Gilstrap in the Eastern District of Texas, which rarely grants stays pending IPR. Judge Gilstrap focused on whether the stay would simplify the issues and noted the IPR did not address all the claims in the patent "Here, the question is whether an instituted IPR covering some as