Form Over Substance? Will The Real Ground Please Stand Up?

The outlines of petitioner estoppel continue to evolve as we hit the ten-year anniversary of the American Invents Act and the introduction of post-grant proceedings. Many district courts have wrestled with the scope of estoppel under 35 U.S.C. § 315(e) for an invalidity ground in litigation that petitioner "raised or reasonably could have raised" in a prior AIA post-grant proceeding, but the term "ground" has also created controversy.¹

Disputes over the meaning of "ground" most often arise where a petitioner asserts patents and printed publications describing a prior art device in an inter partes review ("IPR"), and then seeks to assert the device itself as a basis for invalidity in district court. In seeking to avoid § 315(e) estoppel, petitioners typically argue that devices cannot be asserted in an IPR, which is limited to patents and printed publications, and thus estoppel cannot apply. Patent owners typically argue that § 315(e) statutorily estops