Interference Estoppel Precludes All Arguments That Could Have Been Raised, PTAB Litigation Blog

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This blog has previously discussed the effect of several different types of estoppel.  See, e.g., Estoppel Estopped for Remanded ClaimsReminder: Estoppel May Not Preclude Prior-Art Systems, and PGR Estoppel Applies to Unasserted Art.  Recently, the PTAB again took up the issue of estoppel, this time defining the scope of interference estoppel under 37 C.F.R. § 41.127(a).  The Chemours Company FC, LLC v. Mexichem Amanco Holdings SA, DE C.V., IPR2020-01667, Paper No. 10 (PTAB March 25, 2021). There, the PTAB concluded that interference estoppel does not distinguish between priority and patentability issues, but rather precludes a party from subsequently raising all issues that were or could have been raised in an earlier interference proceeding.

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