Squires Rejects Request for Discretionary Denial, Finding Joinder Can Promote Efficiency 

Need to know

The Director has signaled that a follow-on IPR petition seeking joinder to an already-instituted proceeding is not necessarily an abusive serial challenge and may instead favor institution because joinder consolidates identical challenges into a single, more efficient proceeding.

In a recent decision, Director Squires denied a patent owner’s request for discretionary denial of a follow-on petition for inter partes review (IPR) and motion for joinder. Merck Sharp & Dohme, LLC v. Pogona, LLC, IPR2026-00374, Paper 18 (Director Oct. 26, 2026). The petitioner had previously sought to challenge the same patent, which the Director discretionarily denied. This time around, however, the petitioner sought to join an already-instituted IPR filed by a third party, relying on the same evidence and same challenges to the claims as the third-party petition. The patent owner opposed, citing the earlier discretionary denial and arguing that the instant petition was an abusive serial attack. 

The Director denied the patent owner’s request for discretionary denial on the following basis:

• No trial date had been set in parallel district court litigation between the parties and, thus, evidence did not establish that trial in the parallel litigation would precede final written decision;
• The parties had not yet significantly invested in the parallel litigation;
• The petitioner stipulated that it would not raise in the parallel litigation any invalidity ground it raised or reasonably could have raised in the IPR; and
• Joinder to the instituted third-party IPR would encourage a single resolution of the issues.

Perhaps the most significant element of the decision is the Director’s discussion of joinder. 

The patent owner argued that the petition should be denied because the Director had already denied petitioner’s prior independent petition challenging the same patent and that granting joinder to a previously instituted IPR is the type of follow-on attack on patent rights the Director has sought to curtail. The Director disagreed, characterizing joinder as an “efficiency mechanism” whose “bona fides are to be encouraged.” Because the two petitions present the same evidence and same challenges to the claims, the Director noted that joinder would allow for a singular proceeding to determine the patentability of the challenged claims for all parties. Thus, the Director concluded that joinder in this case would promote “efficient administration of the Office, the ability of the Office to timely complete its [America Invents Act] reviews, and the integrity of the patent system.”

Takeaways

• Prior discretionary denial does not necessarily foreclose a later follow-on petition and motion for joinder: The petitioner’s previous petition was discretionarily denied, but the Director rejected the patent owner’s argument that the instant petition was an abusive serial attack.
• Petitioners seeking joinder should emphasize consolidation and efficiency: Where a follow-on petition and motion for joinder is to an already-instituted IPR, highlight that joinder would result in an efficient, single proceeding.
• Discretionary denial is still a hurdle for joinder petitioners: The Director reiterated that the Office first determines whether a petition warrants institution before considering a motion for joinder. In this case, three items helped the petitioner avoid discretionary denial: (1) district court trial was not scheduled to precede a final written decision, (2) the parties had not significantly invested in the litigation, and (3) the petitioner provided a stipulation.