Last week, the first Precedential Opinion Panel (“POP”) entered a decision examining the scope of joinder available under 35 U.S.C. § 315(c). Proppant Express Investments, LLC v. Oren Techs., LLC, Case IPR2018-00914, Paper 38 (Mar. 13, 2019). The POP made two determinations about the statutory authority of the Patent Trial and Appeal Board (“the Board”) regarding joinder: (1) the Board has discretion to allow same-party joinder and (2) the statute permits joinder of new issues to an existing proceeding. Although the Board had the statutory authority, the POP said the facts of the case did not merit exercising its discretion to allow joinder. We have posted previously on this case and the POP (available here), but a brief summary of the procedural history will aid understanding as to why the POP denied joinder in this case.

Proppant Express challenged Oren Technologies’ U.S. Patent 9,511,929 (“the ’929 patent”) by filing a petition for inter partes review (“IPR”) in 2017. The Board instituted the IPR, but found the petitioner did not adequately support its challenge of claim 4 of the ’929 patent. Proppant Express filed a second IPR in 2018 to correct its challenge of claim 4. Because the second IPR petition was filed after the one-year bar of 35 U.S.C. § 315(b), Proppant Express sought to use an exception to the one-year bar provided in § 315(c) to join the second IPR to the first IPR. The Board denied the motion for joinder and Proppant Express sought review from the POP.

Same-Party Joinder

The first issue before the POP was whether a petitioner may be joined to a proceeding in which it is already a party. Focusing on the statutory language, the POP determined joinder of “any person” in 35 U.S.C. § 315(c) includes a person already a party in a proceeding. The POP recognized the potential for gamesmanship if a per se rule were adopted. A petitioner could wait until an institution decision on an earlier petition to use it as a strategic roadmap to prepare a stronger second petition against the same patent. Similarly, a patent owner could wait to add claims to a district court infringement lawsuit to take advantage of the one year bar on IPR petitions. The POP addressed these concerns by noting that “Congress provided discretion in § 315(c) and not a per se rule one way or the other.” Id. at 11. The POP did not give an exhaustive list of factors to consider, but stated “the Board will exercise this discretion only in limited circumstances—namely, where fairness requires it and to avoid undue prejudice to a party.” Id. at 4. The existence of a time bar under § 315(b) would be one such factor, and to illustrate when such discretion is appropriate, the POP noted two scenarios. A patent owner’s late addition of newly asserted claims in a co-pending litigation may raise concerns of fairness and prejudice, while a petitioner’s mistakes or omissions would not.

Issue Joinder

Further interpreting § 315(c) to address its second issue, the POP determined the Board has statutory authority to join new issues to an existing proceeding. The POP based its decision on both statutory interpretation and legislative history to determine that joinder of a second IPR petition need not be limited to the same issues as the first proceeding. However, similar to the same-party joinder, “the Board will exercise its discretion to allow a time-barred party to join new issues to an existing proceeding only in limited circumstances.” Id. at 15.

One consideration weighing against such discretion is when the petitioner’s own conduct caused the need for joinder. Here, Proppant Express sought to use joinder to correct an erroneous challenge in the first IPR petition. The POP declined to “effectively vitiate the time limitation of § 315(b) and obviate the careful balance the statute and legislative history contemplate” by allowing joinder on these facts. Id. at 20.


The USPTO contemplated the POP would “establish binding agency authority concerning major policy or procedural issues.” This first POP decision has exemplified that purpose by clarifying § 315(c) to allow same-party joinder and new issue joinder, while simultaneously describing the agency policies to contain that discretion. Both patent owners and patent challengers should appreciate the POP’s focus on eliminating gamesmanship in patent litigation.