The Current State Of IPR Estoppel

The inter partes review (IPR) “estoppel” rule, 35 U.S.C. § 315(e), bars a petitioner in an IPR from challenging a patent claim in a proceeding before the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office, a civil action under 28 U.S.C. § 1338, or an International Trade Commission (ITC) proceeding based on “any ground that the petitioner raised or reasonably could have raised during” that IPR. The rationale underlying this bar is that IPRs are intended to “completely substitute for at least the patents-and-printed publications portion of the civil litigation.” 157 Cong. Rec. S1376 (daily ed. Mar. 8, 2011) (statement of Sen. C. Grassley).

Ordinarily, the elements and applicability of common law estoppel/issue preclusion vary somewhat by jurisdiction, and it is an equitable doctrine, discretionary with the court on a case-by-case basis. Section 315(e) “estoppel,” however, is not discretionary; it is a mandatory statutory bar.