The US Court of Appeals for the Federal Circuit has held that state sovereign immunity does not apply to inter partes review (IPR) proceedings. Regents of the Univ. of Minn. v. LSI Corp., Case No. 18-1559 (Fed. Cir. June 14, 2019) (Dyk, J) (add’l views by Dyk, Wallach and Hughes, JJ).

The University of Minnesota (UMN) owns certain patents that it alleged were infringed by LSI. After UMN sued LSI in district court, LSI petitioned for IPR of the asserted patents. UMN moved the Patent Trial and Appeal Board (PTAB) to dismiss on state sovereign immunity grounds. The PTAB held that while state sovereign immunity applied to IPR proceedings, UMN had waived its immunity by filing suit. In a (relatively rare) concurring opinion, the PTAB noted that sovereign immunity was not implicated because IPRs are in rem proceedings in which the US Patent and Trademark Office exercises jurisdiction over patents rather than parties. UMN appealed.

The Federal Circuit affirmed the result but for different reasons. Following Saint Regis Mohawk Tribe v. Mylan Pharms. Inc. (IP Update, Vol. 21, No. 8), which held that tribal immunity does not apply in IPR proceedings, the Court took the next step and held that state sovereign immunity also does not apply to IPR proceedings. The Court reasoned that IPR proceedings are agency reconsideration of a prior patent grant in which the Patent Office acts as the United States in its role as a superior sovereign to protect the public interest in keeping patent monopolies within their legitimate scope. The Court explained that state and tribal sovereign immunity do not differ in a way that is material to the question of whether IPR proceedings are subject to sovereign immunity. The Court thus affirmed the PTAB while avoiding the waiver issue on which the PTAB relied.

In separate “additional views,” the panel echoed the PTAB’s concurrence, noting that state sovereign immunity did not apply here for the additional reason that IPR proceedings “are in substance the type of in rem proceedings to which state sovereign immunity does not apply.”

Practice Note: While citing to Return Mail, this case seems to criticize its reasoning by distinguishing IPR proceedings from district court litigation. Courts seem destined to continue to grapple with how to apply civil procedure concepts developed primarily in district court litigation to post-grant reviews under the America Invents Act.

Having now held that neither tribe nor state patent owners are immune from IPR proceedings, the Court left open the question of whether federal agency patent owners enjoy any such immunity. This may explain why the Court went out of its way to save the waiver issue for another case.

The Federal Circuit discussed the apparent inability of the Patent Office to avoid errors in the initial examination of patent applications, resulting in some interesting dicta for those seeking to attack the presumption of validity.