By David Linden and Dave Maiorana

In February 2023, T-Mobile USA, Inc. (“T-Mobile”) filed petitions requesting four inter partes reviews (“the T-Mobile IPRs”)—two of which challenged U.S. Patent No. 8,630,234 and two of which challenged U.S. Patent No. 10,880,721 with joinder motions.  Previously in June of 2022, T-Mobile had filed four separate petitions challenging the same patents on different prior art.  The PTAB denied each of these earlier petitions on the merits.  Concurrently with the more recent petitions, T-Mobile filed Motions for Joinder seeking to join four IPRs filed by Meta Platforms, Inc. (“Meta”) challenging the same patents (“the Meta IPRs”). filed a Preliminary Response opposing institution of each of the T-Mobile IPRs and an Opposition to each Motion.  Thereafter, T-Mobile filed a Reply in support of each Motion.

Considering whether to institute each of the T-Mobile IPRs, the PTAB noted that each proceeding challenged “the same claims on the same grounds based on the same arguments and evidence presented in the petitions in the Meta IPRs,” each of which was previously considered and instituted by the PTAB.  Therefore, the PTAB summarily found that the T-Mobile IPRs met the threshold determination of establishing a reasonable likelihood that at least one claim is unpatentable.

However, the PTAB considered’s argument that the Board should nonetheless exercise its discretion to deny joinder and institution via its discretion under 35 U.S.C. § 314(a).  In support of the argument for denying institution, cited factors established in General Plastic Industrial Co., Ltd. v. Canon Kabushiki Kaisha, IPR2016-01357 (PTAB Sept. 6, 2017) (“the General Plastic factors”).  The General Plastic factors are intended to establish considerations for the Director to deny institution when a second petition is filed after a previous petition challenging the same patent was denied on its merits, as was the case in the T-Mobile IPRs.  The factors are set forth below:

1)         whether the same petitioner previously filed a petition directed to the same claims of the same patent;

2)         whether at the same time of filing of the first petition the petitioner knew of the prior art asserted in the second petition or should have known of it;

3)         whether at the time of filing of the second petition the petitioner already received the patent owner’s preliminary response to the first petition or received the Board’s decision on whether to institute review in the first petition;

4)         the length of time that elapsed between the time the petitioner learned of the prior art asserted in the second petition and the filing of the second petition;

5)         whether the petitioner provides adequate explanation for the time elapsed between the filings of multiple petitions directed to the same claims of the same patent;

6)         the finite resources of the Board; and

7)         the requirement under 35 U.S.C. § 316(a)(11) to issue a final determination not later than 1 year after the date on which the Director notices institution of review.

T-Mobile argued that the General Plastic factors did not apply in the present case, where they sought to take an “inactive or understudy role” in the Meta IPRs.  The PTAB rejected this contention, noting that the petitions were T-Mobile’s second set of challenges to the patents, and that they would “stand in to continue proceedings that would otherwise be terminated.”  The PTAB emphasized that Meta “ha[d] already been dismissed from those proceedings, and the remaining parties ha[d] jointly moved to terminate them because they ha[d] settled their dispute.”  The PTAB ultimately agreed with’s reliance on the precedential Board decision of Apple Inc. v. Uniloc 2017 LLC, IPR2020-00854 (PTAB October 28, 2020) and their assertion that the General Plastic factors apply broadly to “motions for joinder when considering discretionary denial.”

The PTAB went on to evaluate each General Plastic factor with respect to the petitions in the T-Mobile IPRs.  The PTAB noted that the first factor by its terms favored denying institution: the same petitioner challenged the same patent and each claim challenged in the first set of petitions was also challenged in the second set of petitions.  Evaluating the second General Plastic factor, the PTAB observed that had shown that T-Mobile identified the prior art references relied upon in the T-Mobile/Meta IPRs in preliminary invalidity contentions filed in January of 2022, months before the first set of petitions T-Mobile filed in June of the same year.  Accordingly, the PTAB also found that the second General Plastic factor weighed in favor of denying institution.  The PTAB similarly relied upon this early knowledge of the prior art to find that the fourth factor favored denying institution.

However, the Board found that the third and fifth General Plastic factors weighed against discretionarily denying institution.  Considering the third factor, the PTAB stated that although the petitions in the T-Mobile IPRs were filed after the preliminary response and the Board’s decision denying institution, this guidance arrived after Meta filed the petitions in the Meta IPRs.  “The merits of the [Meta] IPRs thus were fixed before [T-Mobile] received any of this guidance.”  The PTAB proceeded to the fifth factor, and discredited T-Mobile’s justification for not challenging the patents at issue based on the current prior art until it moved to join the Meta IPRs.  Nonetheless, the PTAB noted that the time period of relevant delay is the time period between the first set of petitions and the second set of petitions for the T-Mobile IPRs, and that any delay between its knowledge of the prior art references and its filing of the first set of petitions is irrelevant to the PTAB’s consideration of the fifth General Plastic factor.

The PTAB again noted that T-Mobile “would stand in to continue proceedings that would otherwise be terminated,” finding that the sixth factor weighed in favor of denying institution.  The Board determined that the seventh factor was neutral.  The one-year deadline for entering a Final Written Decision in the Meta IPRs was removed under 35 U.S.C. § 315(c) when Samsung was allowed to join the proceedings, but the Board stated that it maintained its goal of entering a Final Written Decision before the previously existing one-year time period that expires in January 2024.  Finding that four of the seven General Plastic factors favored denying institution and one factor was neutral, the Board exercised its discretion to deny institution of each proceeding as well as the Motions for Joinder.


Petitioners should consider providing robust arguments of unpatentability based on all known prior art references of which they are aware as early as possible.  Later attempts to challenge the same patents may result in statutory preclusion or discretionary denial.

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Dave Maiorana is a trial lawyer with a notable combination of significant experience as a United States Patent and Trademark Office (USPTO) Examiner and more than 25 years litigating complex intellectual property matters. He has represented clients as both plaintiffs and defendants around the country and in the International Trade Commission (ITC). Dave has experience in diverse technology areas, including e-cigarettes, teeth whitening, diapers, fem care, antibodies, self-inflating tires, oxygen concentrators, flash memory, and digital cameras.