The Patent Trial and Appeal Board (the Board) at the U.S. Patent and Trademark Office (USPTO) recently issued a decision interpreting the estoppel provisions of 35 U.S.C. §315(e)(1) in inter partes review (IPR) proceedings. See Dell Inc. v. Electronics and Telecommunications Research Institute, IPR2015-00549 (PTAB, Paper 10, March 26, 2015).

The decision is one of only a handful of institution decisions that have been designated as “representative” by the Board. Under the Board’s standard operating procedures, the “representative” designation is used to bring a decision to the attention of the public from among the numerous “routine” decisions issued by the Board.

In Dell, the petitioner sought inter partes review of claims 1-9 of U.S. Patent No. 6,978,346 (the ‘346 patent) on the ground that the claims would have been obvious over a combination of the Mylex and Hathorn references. The same petitioner had previously sought inter partes review of the same patent based on the same references, though the references were used alone or in combination with other references in the previous petition (petition 1) and not in combination with one another as in the current petition (petition 2). A trial was instituted on claims 1-3 and 5-8 as anticipated by Hathorn in the previous petition 1 and resulted in a final decision of validity of those claims shortly after petition 2 was filed.

The Board denied petition 2, finding that the petitioner was estopped from requesting inter partes review of claim 1-3 and 5-8 under §315(e)(1). Consistent with the statute, the Board also held that claims 4 and 9 – which were not subject to the final written decision in petition 1 – were not precluded by the estoppel provisions of §315(e)(1). The Board, however, exercised its discretion in denying joinder of claims 4 and 9 with another pending petition as “unnecessarily” complicating the other petition and, ultimately, denied institution of those claims as untimely under §315(b).

On the issue of estoppel, the Board found that the petitioner was the same petitioner as in the previous petition 1, the challenged claims of petition 2 were identical to petition 1 (on which the Board issued a final written decision), and that the petitioner “could have raised” the combination of Mylex and Hathorn in petition 1. The Board therefore concluded that the petitioner is estopped from raising the Mylex and Hathorn combination in petition 2. Notably, the Board provided some insight into its interpretation of what a ground that “could have been raised” means:

What a Petitioner “could have raised” was described broadly in the legislative history of the America Invents Act (“AIA”) to include “prior art which a skilled searcher conducting a diligent search would [sic] reasonably could have been expected to discover.” 157 Cong. Rec. S1375 (daily ed. Mar. 8, 2011) (statement of Sen. Grassley). Indeed, the administrative estoppel codified in § 315(e)(1), as was pointed out, would effectively preclude petitioners from bringing subsequent challenges to the patent in USPTO proceedings. See id. at S1376 (statement of Sen. Kyl) (“This [estoppel] effectively bars such a party or his real parties in interest or privies from later using inter partes review or ex parte reexamination against the same patent, since the only issues that can be raised in an inter partes review or ex parte reexamination are those that could have been raised in [an] earlier post-grant or inter partes review.”).

The Board emphasized that both Mylex and Hathorn were known to the petitioner as prior art to the ‘346 patent and were relied upon in the earlier petition 1, albeit for different reasons. Accordingly, the Board found that because the petitioner “could have raised” this ground in the prior petition 1, the petitioner is stopped from asserting this ground in petition 2. The Board stated that “[i]t makes no difference to us that Petitioner may have believed Hathorn to be an anticipatory reference in the [previous] IPR, and that such a belief may have changed during the trial of the [previous] IPR, where we ultimately determined in our Final Written Decision that Hathorn did not anticipate any claim of the ‘346 patent.”

The Board’s designation of this decision as “representative” appears to be a message to the public that the estoppel provisions of §315(e)(1) will be interpreted by the Board consistent with the legislative history of the statute. In light of this relatively strict interpretation of §315(e)(1), those considering an IPR petition should ensure that a comprehensive prior art search is conducted and that all of the best grounds are included in the original petition. Of course, submission of redundant grounds has drawn the ire of the Board, and therefore petitioners must strike a delicate balance when deciding which grounds to include in an IPR petition. Especially in view of the Board’s decision in Dell, petitioners would be wise to consider filing separate petitions on the same patent dedicated to specific sets of claims and/or specific combinations of prior art.