Assignor Estoppel Is Not a Defense in AIA Trials

Recently, the PTAB designated the following decision as precedential: Athena Automation Ltd. v. Husky Injection Molding Sys. Ltd., IPR2013-00290, Paper 18 (PTAB Oct. 25, 2013) (precedential only as to Section II.A).  Athena holds that the doctrine of assignor estoppel is not an exception to 35 U.S.C. § 311(a), which allows “a person who is not the owner of a patent” to file a petition for inter partes review of such patent.

Assignor estoppel is an equitable doctrine that prohibits an assignor of a patent or patent application, or one in privity with the assignor, from attacking the validity of that patent when the assignor is sued for infringement by the assignee. Assignor estoppel operates to prevent the assignor of a patent or patent application “from later contending that what was assigned is a nullity.” Diamond Scientific Co. v. Ambico, Inc., 848 F.2d 1220, 1224 (Fed. Cir. 1988).

In Athena, the patent owner asserted that the petitioner is barred from bringing its petition under the doctrine of assignor estoppel. The PTAB disagreed, holding that “an assignor of a patent, who is no longer an owner of the patent at the time of filing, may file a petition requesting inter partes review.” Referencing the language of 35 U.S.C. § 311(a), the PTAB stated that “this statute presents a clear expression of Congress’s broad grant of the ability to challenge the patentability of patents through inter partes review.” The PTAB also compared the AIA to the statute governing ITC investigations. The PTAB noted that while Congress explicitly provided that “[a]ll legal and equitable defenses may be presented” in a 337 proceeding at the ITC, no similar statutory mandate was provided in the AIA concerning inter partes review at the Patent Office.

On appeal, the Federal Circuit, in a split decision, determined that it lacked jurisdiction to review the Board’s determination concerning the applicability of assignor estoppel to inter partes review proceedings. Husky Injection Molding Sys. Ltd. v. Athena Automation Ltd., 838 F.3d 1236 (Fed. Cir. 2016).

The PTAB’s precedential decision can be found here. To date, Athena is the ninth decision rendered in an AIA trial that the PTAB has designated as precedential. We previously summarized the other eight precedential decisions here.

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