In a recent Inter Partes Review (“IPR”) institution decision, Apotex v Wyeth (IPR2015-00873, Paper No. 8), the USPTO’s Patent Trial and Appeal Board (the “Board”) found that some previously-asserted grounds of invalidity were not subject to statutory estoppel in a follow-on IPR Petition. 

The patent statute states that, in IPR proceedings, when an IPR petitioner challenges a patent and is unsuccessful (in a final written decision by the Board), the petitioner cannot in a later IPR assert “any ground that the petitioner raised or reasonably could have raised” in the first IPR.  35 U.S.C. §315(e)(1).  The statute’s language does leave open the question of the scope of this estoppel provision.  For example, some petitioners file multiple challenges of a claim, only to have one or more of the challenges be denied by the Board as “redundant,” such that only one of the resulting challenges is addressed in the Board’s final written decision.

In Apotex v Wyeth, Apotex filed a first IPR petition asserting numerous grounds of unpatentability.  Some of those grounds were denied as redundant, while IPR trial was instituted as to other grounds.  Apotex was ultimately unsuccessful in the IPR trial, and the Board issued a final written decision finding the challenged claims not unpatentable.  Apotex then filed a second IPR petition asserting one ground previously denied as “redundant” and one new ground.  In their September 16 institution decision, the Board held that the ground asserted in the first IPR petition but denied as “redundant” was not estopped under 35 USC §315(e)(1).  The Board also held that the newly asserted ground could have been raised in the previous petition, and, thus was estopped from being asserted in the later IPR.  Despite those holdings, the Board denied institutions on the grounds that the merits of Apotex’s challenge failed to meet the threshold requirement for instituting an IPR trial.

This decision is important to both Petitioners and patent owners in Board proceedings in which petitions contain multiple grounds for challenging the claims and one or more of those grounds are denied institution by the Board.  Given this result, despite the fact that the Board may only consider one or two grounds in any given IPR, there could be strategic advantages for a petitioner to file additional grounds of invalidity, in some specific situations.  Furthermore, the implications of the scope of estoppel on 35 U.S.C. §315(e)(1) may also carry over to §315(e)(2), directed to estoppel in civil actions, opening up additional opportunities and strategies in the IPR space that will apply to district court litigation.