The Patent Trial and Appeal Board (PTAB) designated as precedential its 2013 decision that assignor estoppel is not a defense for patent owners in inter partes review (IPR) proceedings. Athena Automation Ltd. v. Husky Injection Molding Systems Ltd., Case No. IPR2013-00290, Paper 18 (PTAB, Oct. 25, 2013) (designated precedential Aug. 2, 2017). This is the 10th American Invents Act post-grant proceeding identified as precedential.

Patent owner Husky Injection Molding Systems defended the IPR on the basis that the petitioner, Athena Automation, was estopped from challenging the validity of the patent under the doctrine of assignor estoppel because one of the named inventors of the patent was Athena’s founder, president, CEO and one of its two directors, and therefore was in privity with Athena.

The PTAB rejected Athena’s argument by stating that assignor estoppel was not a basis for denying an IPR petition under § 311(a). The statute provides that “a person who is not the owner of a patent may file with the Office a petition to institute an inter partes review of the patent.” Thus, an assignor of a patent who is not an owner at the time of filing may file a petition requesting IPR, according to the PTAB.

Husky appealed the issue of assignor estoppel, but the US Court of Appeals for the Federal Circuit declined to decide the issue, concluding that it lacked jurisdiction to review the PTAB’s institution decision. 

Practice Note: At least for the present, assignor estoppel cannot be used as a defense in IPRs, based on the designation of the PTAB’s decision as precedential and the Federal Circuit’s decision that it lacks jurisdiction to review the issue.