Trending at the PTAB: Shifts in Parallel Proceedings Strategy

1. Consistent Positions in Parallel Proceedings: Practitioners should keep consistent positions across the PTAB and federal courts. Inconsistencies, such as those in Cambridge Mobile Telematics Inc. v. Sfara Inc., could lead to the PTAB denying institution. This underscores the importance of aligning arguments and avoiding discrepancies that can undermine a case.
   
   
2. Discretionary Denial Based on Prior Court Rulings: Discretionary denials by the PTAB can be influenced by prior district court rulings. The PTAB declined to institute a review in Hulu LLC v. Piranha Media Distribution LLCdue to claims that had already been invalidated under Section 101 by a district court. Petitioners should act fast to file IPRs before non-prior art grounds claims are resolved in court, potentially barring further PTAB review.
   
   
3. Federal Circuit's Clarification on IPR Estoppel: The Federal Circuit's decision in Ingenico Inc. v. Ioengine LLC clarified IPR estoppel, confirming that estoppel applies only to prior art based on patents or printed publications. This permits previously used prior art systems to be raised in district court if they include public use or on-sale bar grounds not eligible for IPR, thus providing more opportunities for patent challengers in litigation.

With discretionary denials on the rise in recent months,[1] practitioners involved with parallel proceedings should be aware of the changing dynamic between the Patent Trial and Appeal Board and federal courts and adjust their strategies accordingly.

Two recent discretionary denials and one U.S. Court of Appeals for the Federal Circuit decision on inter partes review estoppel highlight some of these recent changes and shed light on current strategies for those navigating parallel proceedings.

A Cautionary Tale About Taking Inconsistent Positions in Parallel Proceedings

While it has long been best practice, a recent PTAB opinion stresses the importance of keeping positions consistent in parallel proceedings and the potential pitfalls should practitioners fail to do so.[2]

In Cambridge Mobile Telematics Inc. v. Sfara Inc., petitioner CMT argued for a plain and ordinary construction of the "component" terms at the PTAB, but took a different position in district court, asserting that the same "component" terms were means-plus-function terms governed by Section 112(f) and indefinite in view of the specification.[3]

At the PTAB, the patent owner, Sfara, argued that the board should deny institution because CMT failed to address whether the "component" terms were means-plus-function limitations, which rendered the petition deficient under Title 37 of the Code of Federal Regulations, Section 42.104(b)(3).[4]

Sfara pointed to the Consolidated Trial Practice Guide, which provides "[w]here claim language may be construed according to 35 U.S.C. § 112(f), a petitioner must provide a construction" and "[a] petitioner who chooses not to address construction under § 112(f) risks failing to satisfy the requirements of 37 C.F.R. § 42.104(b)(3)."[5]

CMT responded that the plain and ordinary meaning was consistent with its litigation position and argued that "the Board need not expressly construe any term."[6] But the board rejected CMT's explanation, pointing to how adamant CMT was arguing that these were means-plus-function limitations in district court.[7]

The board interpreted the issue as dispositive, finding that "37 C.F.R. § 42.104(b)(3) mandates that the Petition 'identify the specific portions of the specification that describe the structure, material, or acts corresponding to each claimed function.'"[8] And because CMT failed to do so, the PTAB found the petition deficient and denied institution.

With the PTAB issuing more discretionary denials, petitioners need to be aware that even the slightest of inconsistencies may lead to the board denying institution and leave patent challengers with federal courts as their only recourse. Patent challengers should also do their best to harmonize claim construction positions across forums, and in rare circumstances where it is necessary to take inconsistent positions, make sure to clearly justify any divergence or discrepancies.

Discretionary Denial Due to Prior District Court Ruling of Invalidity Under 101

In another case that was recently designated informative, Hulu LLC v. Piranha Media Distribution LLC, on April 17 interim director Coke Morgan Stewart granted director review of the board's earlier institution decision and reversed the institution decision in light of a prior district court ruling that the challenged claims were invalid under Title 35 of the U.S. Code, Section 101.[9]

The director reasoned that institution would be inefficient and potentially threaten the integrity of the patent system because the district court judge already invalidated the patent under Section 101.[10] In explaining her decision, Coke emphasized that, because "patent claims already stand invalid, it is unnecessary to institute another proceeding to review for patentability on other grounds."[11]

Now more than ever, petitioners should be moving quickly to file IPRs, and that may be especially the case where they are presenting non-prior art grounds in a motion to dismiss or early summary judgment motion in a related proceeding. Once the claims have been found invalid based on non-prior art grounds, such as Section 101, IPRs may no longer be an option for patent challengers.

Clarification From the Federal Circuit on the Scope of IPR Estoppel in District Court

Another recent decision that affects parallel proceedings is Ingenico Inc. v. Ioengine LLC, in which the Federal Circuit clarified on May 7 that the scope of IPR estoppel under Section 315(e)(2).[12]

At summary judgment, Ioengine moved to preclude Ingenico from relying on "documentation related to DiskOnKey Upgrade software" because Ingenico could have been reasonably expected to raise it earlier during the IPRs.[13]

The district court judge ruled that Ingenico was precluded from relying on this prior art at trial to prove invalidity, except to the extent the prior art formed a part of a "substantively different combination of references that could not have been reasonably raised in the IPRs."[14]

At trial, Ingenico presented a prior art USB device, known as the DiskOnKey device, which was manufactured to include a firmware upgrade and sold before the date of the invention. Ingenico relied on this device, among other evidence, to invalidate the claims.[15]

Ingenico argued that the DiskOnKey system invalidated the asserted claims as anticipated or obvious because it was on sale or in public use.[16] The jury found that the asserted claims were invalid as anticipated and obvious based on the DiskOnKey system.[17] Ioengine moved for judgment as a matter of law of no invalidity, or alternatively for a new trial, but the district court denied these motions, and Ingenico appealed to the Federal Circuit.[18]

In its decision, the Federal Circuit affirmed the district court ruling, emphasizing that IPR estoppel only bars arguments based on prior art grounds, i.e., invalidity theories under Sections 102 or 103, that "could have reasonably been raised" during the IPR.[19]

Importantly, the court noted that IPR proceedings are limited to grounds based on "patents or printed publications" only,[20] but here, the court found the DiskOnKey system could not have been raised in IPR proceedings.[21] As such, the court held that evidence already used in an IPR could be used in district court for grounds that are ineligible for IPR, such as public use, on-sale bar or use by others.[22]

Resolving a previous district court split, this Federal Circuit decision expands the opportunities for patent challengers to raise prior art systems at trial where there was a previously unsuccessful IPR challenge.

While IPR estoppel is still an obstacle, patent challengers should feel more comfortable asserting prior art system-based invalidity theories in district court, even where some of that evidence was raised or could have been raised before the PTAB.

Takeaways From Recent Decisions

As the cases above highlight, the recent changes at the PTAB and the Federal Circuit's recent clarification of IPR estoppel have had a meaningful impact on parallel proceedings.

Patent challengers need to continue to file IPRs quickly and be extra cautious to avoid discretionary denials at the PTAB.

Meanwhile, patent owners may have a few more arrows in their quivers at the PTAB, but they now face narrower IPR estoppel protections in district court.

Whether one has better odds at the PTAB or in federal court is still largely case dependent, but those involved with parallel proceedings need to continue to follow closely as more cases and guidance come out from the PTAB.

Endnotes

[1] See e.g., 2025 Q1 PTAB Discretionary Denial Report: Fintiv in Overdrive, Unified Patents (May 27, 2025), available at https://www.unifiedpatents.com/insights/2025/5/16/2025-q1-ptab-discretionary-denial-report-fintiv-in-overdrive(noting no discretionary denials in January and February 2025, eight discretionary denials in March 2025, and twenty-nine discretionary denials in April 2025); see also Coke Morgan Stewart, Interim Processes for PTAB Workload Management, USPTO (Mar. 26, 2025), available at https://www.uspto.gov/sites/default/files/documents/InterimProcesses-PTABWorkloadMgmt-20250326.pdf (creating a bifurcated review process whereby the Director has first and final say on discretionary denial). 

[2] Cambridge Mobile Telematics Inc. v. Sfara Inc. , IPR2024-00952, Paper 12 (PTAB Dec. 13, 2024).

[3] See id. at 6-7.

[4] Id. at 7.

[5] See id. at 6. 37 C.F.R. §42.104(b)(3) requires

[w]here the challenged claim to be construed contains a means-plus-function or step-plus-function limitation as permitted under 35 U.S.C. 112(f), the construction of the claim must identify the specific portions of the specification that describe the structure, material, or acts corresponding to each claimed function.

[6] Id. at 7.

[7] Id. at 7-9.

[8] Id.

[9] Hulu LLC v. Piranha Media Distribution LLC , IPR2024-01252 & IPR2024-01253, Paper 27 (PTAB Apr. 17, 2025).

[10] Id. at 3.

[11] Id. at 2.

[12] Ingenico Inc. v. IOENGINE LLC, 136 F.4th 1354 (Fed. Cir. 2025).

[13] Id. at 1360.

[14] Id.

[15] Id.

[16] Id.

[17] See id.

[18] Id. at 1360-61.

[19] Id. at 1364-66.

[20] Id. at 1365.

[21] Id. at 1366-67.

[22] Id.