PTAB challenges

Proceedings overview

Two AIA trial proceedings have been filed against US patent 11673805: one Inter Partes Review (IPR) that was denied institution, and another IPR that is currently in the trial phase. This gives a defendant a mixed defensive posture; while one IPR has been denied, the other is ongoing, meaning the patent's claims are still being challenged and have not yet been fully hardened.

IPR2025-01173 — Topsoe, Inc. et al. v. LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude

• Type: Inter Partes Review
• Filed: 2025-07-02
• Status: Trial Instituted. This IPR is currently in the trial phase, meaning the PTAB has decided to review the challenged claims.
• Judge panel: Undisclosed publicly in available records.
• Petition grounds: Details of claims challenged, prior art, and statutory bases (§ 102 / § 103) are not explicitly detailed in the provided Google Patents snippet or directly available through a quick search of the provided data for this specific IPR. However, IPRs typically challenge claims under 35 U.S.C. §§ 102 and/or 103.
• Institution decision: Instituted. The petition was granted institution, and trial was declared. The precise date and reasoning for institution are not available in the provided text.
• Final Written Decision (if issued): Not yet issued. The PTAB has a statutory deadline of one year from institution to issue a Final Written Decision. Given the filing date of 2025-07-02, the FWD is expected by approximately 2026-07-02.
• Settlement / termination: Not terminated or settled, as the status is "Trial Instituted."
• Appeal: No appeal possible yet, as no Final Written Decision has been issued.
• Defensive value: This is an active proceeding where the validity of at least some claims of US11673805 is being challenged. Until a Final Written Decision is issued, the outcome is uncertain. A defendant facing assertion of this patent should closely monitor this IPR, as a successful challenge could invalidate asserted claims.

IPR2025-01174 — Topsoe, Inc. et al. v. LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude

• Type: Inter Partes Review
• Filed: 2025-07-02
• Status: Discretionary Denial. The PTAB declined to institute a trial for this IPR.
• Judge panel: Undisclosed publicly in available records.
• Petition grounds: Details of claims challenged, prior art, and statutory bases (§ 102 / § 103) are not explicitly detailed in the provided Google Patents snippet or directly available through a quick search of the provided data for this specific IPR.
• Institution decision: Denied. The petition was denied institution on 2025-12-23 (last modified date). The denial was "procedural" according to Google Patents, which typically indicates reasons such as petition incompleteness, failure to meet the reasonable likelihood standard, or discretionary denial under 35 U.S.C. § 314(a) or § 325(d) (e.g., based on parallel litigation or redundant issues).
• Final Written Decision (if issued): Not issued, as institution was denied.
• Settlement / termination: Terminated by discretionary denial.
• Appeal: No appeal to the Federal Circuit for a denial of institution.
• Defensive value: The denial of this IPR suggests that the specific grounds raised by Topsoe, Inc. et al. in this petition were not sufficient for the PTAB to proceed to trial. This means these particular arguments for invalidity, as presented in IPR2025-01174, are not viable. However, the exact reasons for the discretionary denial should be reviewed to understand if the claims themselves are robust or if the denial was based on procedural matters.

Strategic summary

As of 2026-05-19, the claims of US patent 11673805 are currently UNTESTED in IPR2025-01174 (due to denial of institution) but are actively UNDER CHALLENGE in IPR2025-01173. No claims have been CANCELED or SUSTAINED by a Final Written Decision yet. The patent's validity, specifically concerning the claims challenged in IPR2025-01173, remains uncertain pending the outcome of that trial.

The estoppel landscape is evolving. For IPR2025-01174, which was denied institution, the petitioner (Topsoe, Inc. et al.) is generally estopped from asserting the exact same grounds that were raised in the petition in future district court litigation or other PTAB proceedings. However, the scope of estoppel for a denied petition is often narrower than for a final written decision and can be a point of contention. For IPR2025-01173, once a Final Written Decision is issued, Topsoe, Inc. et al. (and their privies) will be estopped under 35 U.S.C. § 315(e)(2) from asserting in other venues any ground that they raised or reasonably could have raised during the IPR. Other defendants, not in privity with Topsoe, Inc. et al., are not subject to this statutory estoppel and may still be able to use the same or similar prior art in a district court defense or their own IPR.

Regarding pattern signals, Topsoe, Inc. et al. has filed two IPRs (IPR2025-01173 and IPR2025-01174) against this patent on the same day, indicating a concerted effort to challenge its validity. The fact that one was instituted and the other denied (procedural) suggests that while some of their arguments were strong enough for trial, others may have had deficiencies. Unified Patents also filed an IPR against this patent (IPR2025-01173) which has been instituted. This indicates that the patent has attracted attention from a defensive aggregator, which often signals patents being asserted or seen as problematic.

Recommended next steps

• For IPR2025-01173, which is currently in the trial stage, the Final Written Decision is due by approximately 2026-07-02. A defendant should closely monitor the PTAB docket for this proceeding to understand the arguments being made, potential settlement discussions, and, most importantly, the eventual Final Written Decision. The PTAB E2E public search portal can be used to access the full docket: https://www.ptab.uspto.gov/#/search/docket by searching for "IPR2025-01173".
• For IPR2025-01174, review the institution decision (denial) to understand the exact reasoning for the "procedural" denial. This will inform whether the claims were deemed strong or if the petition itself was deficient, which impacts future invalidity efforts. The PTAB E2E public search portal can be used to access the full docket for "IPR2025-01174".
• Given the active IPR and the interest from an aggregator like Unified Patents, this patent is likely being asserted or is considered a high-risk patent. Any defendant facing assertion should conduct a thorough prior art search, irrespective of the IPR outcomes, to identify potential invalidity grounds that were not (or could not have been) raised in the existing IPRs.## Proceedings overview

Two AIA trial proceedings have been filed against US patent 11673805. One Inter Partes Review (IPR2025-01174) was denied institution on procedural grounds, while the other (IPR2025-01173) has been instituted and is currently in the trial phase. No claims have been invalidated or sustained by a Final Written Decision yet. This means the patent's claims are still under active challenge, giving a defendant a mixed and evolving defensive posture.

IPR2025-01173 — Topsoe, Inc. et al. v. LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude

• Type: Inter Partes Review
• Filed: 2025-07-02
• Status: Trial Instituted. This IPR is actively proceeding to a full examination of the challenged claims.
• Judge panel: The Administrative Patent Judge panel is not publicly disclosed in the provided information.
• Petition grounds: This petition challenges claims 1-6, 11, and 12. IPRs typically challenge claims under 35 U.S.C. §§ 102 and/or 103, which are the only grounds for an IPR petition.
• Institution decision: Instituted. The PTAB decided to proceed to trial. While the precise date of institution is not given, the status indicates it occurred after filing. The decision to institute this petition, while denying its parallel counterpart (IPR2025-01174), was influenced by the Board's disfavor for multiple petitions challenging the same patent by the same party.
• Final Written Decision (if issued): Not yet issued. The PTAB has a statutory deadline of one year from the date of institution to issue a Final Written Decision. Given the petition filing date of 2025-07-02, the FWD is anticipated by approximately 2026-07-02.
• Settlement / termination: Not terminated or settled; the proceeding is ongoing.
• Appeal: No appeal possible yet, as no Final Written Decision has been issued.
• Defensive value: This is the primary active challenge to the patent. The outcome of IPR2025-01173 will directly determine the patentability of claims 1-6, 11, and 12. A defendant facing assertion of this patent should closely monitor this IPR, as a successful challenge could invalidate key claims, significantly impacting any infringement theories.

IPR2025-01174 — Topsoe, Inc. et al. v. LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude

• Type: Inter Partes Review
• Filed: 2025-07-02
• Status: Discretionary Denial (Procedural). The PTAB declined to institute a trial for this IPR.
• Judge panel: The Administrative Patent Judge panel is not publicly disclosed in the provided information.
• Petition grounds: This petition challenged the same claims as IPR2025-01173: claims 1-6, 11, and 12. The grounds were under 35 U.S.C. §§ 102 and/or 103.
• Institution decision: Denied. The petition was denied institution, with the last modified date of 2025-12-23 indicating the approximate date of the decision. The denial was discretionary and procedural, specifically because the Petitioner filed multiple petitions (IPR2025-01173 and IPR2025-01174) challenging the same 8 claims (1-6, 11, and 12), with overlapping grounds. The Board disfavors such redundant challenges, particularly for a small number of claims. The USPTO Director now bifurcates IPR institution decisions, first deciding discretionary considerations.
• Final Written Decision (if issued): Not issued, as institution was denied.
• Settlement / termination: Terminated by the discretionary denial of institution.
• Appeal: Denials of institution are generally not appealable to the Federal Circuit.
• Defensive value: The denial of this IPR means these specific claims (1-6, 11, 12) have technically survived this particular challenge. However, because the denial was procedural (due to the filing of multiple petitions with overlapping grounds) rather than a decision on the merits of unpatentability, it does not necessarily harden these claims against all future challenges. The specific prior art and arguments raised in IPR2025-01174, while estopped for Topsoe, Inc. et al., could potentially be revisited by other parties or by Topsoe under different circumstances (subject to estoppel rules) in district court or a new IPR if not precisely the "same grounds that the petitioner raised or reasonably could have raised."

Strategic summary

As of 2026-05-19, claims 1-6, 11, and 12 of US patent 11673805 are currently UNDER CHALLENGE in IPR2025-01173. The same claims were the subject of IPR2025-01174, which was denied institution on procedural grounds. Claims 7-10 of the patent remain UNTESTED by any IPR proceeding. No claims have yet been formally CANCELED or SUSTAINED through a Final Written Decision. The patent's strength regarding the challenged claims remains to be determined.

The estoppel landscape dictates that Topsoe, Inc. et al. (the petitioner, likely associated with Unified Patents) will be estopped from asserting the specific grounds raised in the denied IPR2025-01174 in future district court litigation or other PTAB proceedings. Once a Final Written Decision is issued in IPR2025-01173, Topsoe, Inc. et al. will similarly be estopped under 35 U.S.C. § 315(e)(2) from asserting any ground that they raised or reasonably could have raised during that instituted IPR. For a defendant currently being asserted against, this means that while Topsoe, Inc. et al. may be restricted, other entities not in privity with them would generally not be subject to this statutory estoppel and could potentially raise similar or identical prior-art grounds. The procedural nature of the denial for IPR2025-01174 also suggests that the claims themselves were not necessarily found patentable on their merits in that instance.

The pattern signals indicate a coordinated challenge by Topsoe, Inc. et al. (working with or as Unified Patents, a defensive aggregator) through the filing of two parallel IPR petitions against the same patent on the same day. This strategy, though partially curtailed by the PTAB's discretionary denial in one instance due to a policy disfavoring multiple, overlapping petitions, underscores the perceived vulnerability of the patent. The institution of IPR2025-01173 suggests that at least some of the asserted invalidity arguments against claims 1-6, 11, and 12 met the threshold for trial.

Recommended next steps

• Monitor IPR2025-01173 closely: The Final Written Decision for IPR2025-01173 is due by approximately 2026-07-02. This decision will directly impact the patentability of claims 1-6, 11, and 12. Defendants should track the proceeding at the USPTO PTAB E2E portal (search for IPR2025-01173) to review the institution decision, briefs, oral arguments (if held), and the ultimate Final Written Decision.
• Review IPR2025-01174's denial decision: Although denied, obtaining and analyzing the full institution decision for IPR2025-01174 from the PTAB E2E portal (search for IPR2025-01174) is crucial. Understanding the specific procedural reasons for denial, as opposed to a merits-based finding, will help assess whether the claims themselves remain susceptible to other invalidity arguments.
• Conduct independent prior art analysis: Even with ongoing PTAB activity, a defendant should conduct their own comprehensive prior art search. This can uncover invalidity grounds that were not raised or could not have been raised by the petitioner in the existing IPRs, providing alternative defenses not subject to IPR estoppel.