Lack of Redundancy May Not Be Enough to Justify Follow-On Petitions for IPR

In the 2017 precedential decision General Plastic Co. v. Canon Kabushiki Kaisha, the PTAB established a set of seven non-exclusive factors  that it will consider in exercising its discretion under 35 U.S.C. § 314(a) to deny follow-on petitions. Two recent PTAB decisions analyzing General Plastic suggest a lack of redundancy between the petitions may not be enough to justify instituting a follow-on petition.  Instead, a primary consideration guiding the PTAB may be whether the petitioner could have raised the arguments in an earlier-filed petition.

In Apple Inc. v. Corephotonics Ltd., the PTAB concluded that an unexplained six-week delay between the filing of one petition and a follow-on petition, both by the same petitioner, strongly favored a § 314(a) denial of institution, even though the follow-on petition presented different grounds for invalidity and relied on different prior art.

In this case, the petitioner had argued that the second-filed petition was not redundant of the earlier petition because the grounds were premised on an anticipation theory, while the earlier petition’s grounds were premised on obviousness over different prior art. The PTAB was unmoved and emphasized that the petitioner did “not provide any explanation as to when it learned of” the new reference relied upon in the follow-on petition, and did not explain the six-week delay between the two petitions. The PTAB also noted that the petitioner did not explain how its anticipation grounds differed substantively from its obviousness grounds in the earlier-filed petition.

The PTAB concluded that the petitioner’s unexplained delay was relevant to several of the General Plastic factors, and weighed “strongly in favor” of a discretionary denial of institution. Although the PTAB acknowledged that the patent owner did not file a preliminary response to the earlier-filed petition, which weighed against a discretionary denial, and that two factors were neutral, those findings were not sufficient to dissuade the PTAB from denying institution.

Eight days later, in Samsung Electronics Co. v. Iron Oaks Technologies, the PTAB concluded that an eight-month delay between the filing of one petition and a follow-on petition did not favor a § 314(a) denial of institution when the petitions were filed by two different petitioners. As in Apple, the earlier-filed petition in Samsung was based on different grounds and different prior art than the follow-on petition. Unlike in Apple, however, the earlier-filed petition in Samsung had been filed by “a different entity.”

While the PTAB in Samsung considered the seven non-exhaustive General Plastic factors, it also discussed two additional factors: the prejudice to the subsequent petitioner if institution is denied and the first petitioner terminates its proceedings; and whether the multiple petitions are “a direct result of Patent Owner’s litigation activity.” Both additional factors weighed against a discretionary denial of the follow-on petition. The PTAB concluded, “We decline to wield [Patent Owner’s] own litigation activities as a shield in this inter partes review.”

As to the seven General Plastic factors, the PTAB found that none of those factors favored a discretionary denial even though the petitioner provided no specific explanation for the eight-month delay.


These two recent PTAB decisions reiterate that, when a patent has already been challenged in a petition for inter partes review, it is critical that the petitioner address the application of § 314(a) in its petition.

The decisions illustrate that, without more, a difference in the grounds and prior art is not sufficient to justify a follow-on petition by the same petitioner. Apple also suggests that, without an explanation, a six-week delay between petitions filed by the same petitioner is too long even if the later petition relies on entirely different references. Moreover, taken together, Apple and Samsung suggest that potential for prejudice to the petitioner weighs against a discretionary denial, while a lack of prejudice (e.g., an unexplained delay between two petitions by the same petitioner) favors a discretionary denial.

Going forward, filing multiple petitions on different days without any explanation is risky. Petitioners challenging a patent that has been challenged in an IPR by a different entity should emphasize the prejudice that the petitioner could face if institution is denied and the earlier-filed IPR terminates. Patent owners should identify in the preliminary response any fairness factors weighing against instituting a follow-on petition, and in particular should seek to demonstrate a lack of prejudice to the petitioner.