The Leahy-Smith America Invents Act (AIA) of 2011 created post-grant review (PGR) and inter partes review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office. These new proceedings provide opportunities for non-patent owners to challenge claims on a relatively accelerated timeline, between twelve to eighteen months post-institution, and have become fairly popular, with over 11,000 patents challenged.
After a final decision, these proceedings carry estoppel, including statutory and collateral estoppel among others, for petitioners as well as patent owners.1Each type has unique circumstances (when it arises and where), standards (who has the burden), and applications (who is deciding the questions).
Statutory estoppel. When creating PTAB proceedings, Congress recognized the need to protect patent owners from repeated challenges and specifically included statutory estoppel provisions applicable before the Office, in District Courts, and at the International Trade Commission.
Statutory estoppel is triggered with a final written decision and applies not only to the petitioner but its real parties in interest and those in privity with it.
35 U.S.C. ' 315(e)(1) sets forth the estoppel before the USPTO:
The petitioner in an inter partes review of a claim in a patent under this chapter that results in a final written decision under section 318(a), or the real party in interest or privy of the petitioner, may not request or maintain a proceeding before the Office with respect to that claim on any ground that the petitioner raised or reasonably could have raised during that inter partes review.
35 U.S.C. ' 315(e)(2) sets forth the estoppel in civil actions:
The petitioner in an inter partes review of a claim in a patent under this chapter that results in a final written decision under section 318(a), or the real party in interest or privy of the petitioner, may not assert either in a civil action arising in whole or in part under section 1338 of title 28 or in a proceeding before the International Trade Commission under section 337 of the Tariff Act of 1930 that the claim is invalid on any ground that the petitioner raised or reasonably could have raised during that inter partes review.
Civil actions. The scope of statutory estoppel in civil actions, especially as to what challenges a petitioner "reasonably could have raised during" a PTAB proceeding, has evolved over the past several years. Early on, the PTAB adopted a practice of partial institution where some grounds raised by a petitioner may not have been instituted.
In view of this practice, statutory estoppel did not apply to those grounds that were raised but not instituted. This initial framework came as a result of the Federal Circuit's decision in Shaw, which established a rationale that grounds not instituted cannot be estopped because they could not have been "reasonably raised" before the PTAB.2
After Shaw, district courts differed on the fuller scope of statutory estoppel. Some courts applied Shaw (as an exception to estoppel) broadly, finding estoppel applied only to grounds that were raised and instituted, while other courts applied Shaw (as an exception to estoppel) narrowly, finding estoppel applied only to grounds that were raised but not instituted.3
Those courts applying Shaw narrowly began adopting the "reasonable searcher" standard when making estoppel determinations to assess what grounds a petitioner could have reasonably raised.
As the law developed, patent owners focused on demonstrating what a skilled searcher would have found by (i) identifying "the search string and search source that would identify the allegedly unavailable prior art," and (ii) presenting "evidence, likely expert testimony, why such a criterion would be part of a skilled searcher's diligent search."4
Two years after Shaw, the Supreme Court decided SAS, overruling the PTAB's practice of partial institution.5 While SAS did not interpret the estoppel statutes (' 315, 325), it nevertheless eliminated the possibility of petitioned yet non-instituted grounds, the fact pattern specifically at issue in Shaw. Four years after SAS, the Federal Circuit overruled Shaw in California Institute of Technology v. Broadcom Ltd., focusing on the statutory text and explaining that estoppel applies:
not just to claims and grounds asserted in the petition and instituted for consideration by the Board, but to all grounds not stated in the petition but...
