The Patent Office POPs the Door Open for Same-Party Joinder

In September 2018, the Patent Office created the Precedential Opinion Panel (or “POP”) to increase transparency and predictability of proceedings before the PTAB by establishing precedent that would guide all PTAB judges. In March 2019, the POP released its first opinion, which held that the PTAB may, in limited circumstances, join both a petitioner to a proceeding in which it is already a party and join new issues to an existing proceeding.

In Proppant Express Investments, LLC v. Oren Technologies, LLC, the PTAB instituted an IPR trial, but not as to one of the challenged claims because the petitioner had erroneously failed to account for all of the claim limitations in its grounds for the challenge. Although the one-year time period for filing petitions had passed, the petitioner filed a new petition targeting that one non-instituted claim. The petitioner sought to avoid the one-year time bar by asking the PTAB to join its new petition to the previously instituted IPR. Under Section 315(b), petitions are exempt from the one-year time bar if they are joined to an instituted IPR.

In ruling on the new petition and the motion for joinder, the PTAB broke with previous IPR decisions and determined it has authority only to join “other parties to existing proceedings without introducing new issues of patentability.” Because the second petition was time-barred, the PTAB denied institution. The petitioner requested rehearing of the PTAB’s decision, and the POP chose to decide the case.

The POP interpreted the statute, 35 U.S.C. § 315(c), according to its plain meaning, emphasizing that its language permits the PTAB to join “any person who properly files a petition” that warrants institution of an IPR. The POP held that “any person” includes the prior petitioner. Further, the POP held that joinder may add new challenges to instituted IPRs, since nothing in the statute prohibits raising new issues, and the legislative history of Section 315(c) suggests Congress contemplated that joined petitions may contain new issues.

Although the POP held that the PTAB could join new claims to an instituted IPR, it held that joinder was not appropriate here. The POP stressed that joinder is generally appropriate “only in limited circumstances where fairness requires it and to avoid undue prejudice to a party.” The POP explained that fairness and prejudice concerns could arise when the patent owner asserts new claims in a co-pending litigation, but not when a petitioner merely seeks to correct its “mistakes or omissions.” In this case, the first petition failed as to the non-instituted claim because the petitioner had mistakenly failed to account for all of the claim’s limitations, thus refusal to exercise discretionary joinder was appropriate.


Although the POP held that joinder of existing parties and new claims into existing proceedings is possible, petitioners should not count on joinder as a strategy to fix mistakes or buy extra time. The POP warned specifically against attempts to use joinder to “game the system” and noted that the PTAB may also deny institution based on its discretion under Section 314(a).

Petitioners still may take some solace in this decision, however, since the POP declined to rigidly apply Section 315(b)’s time bar to joinder scenarios. The POP suggested that the PTAB could permit joinder when the patent owner adds unchallenged claims to the list of asserted claims in litigation after the one-year deadline for IPR.

Newly asserted claims past the one-year deadline will likely not be the only situation where joinder will be permitted. The POP declined to provide “an exhaustive list of those circumstances” which may warrant joinder or denial of joinder. Future cases will offer a better sense of this list over time.