PTAB challenges

Proceedings overview

A single AIA trial proceeding, IPR2025-01060, has been filed against US Patent 11275092. This proceeding reached a status of "Discretionary Denial" at the institution stage, meaning the trial was not instituted. As a result, no claims of US11275092 have been challenged on their merits or invalidated through PTAB proceedings. This outcome generally strengthens the patent's defensive posture, as it successfully withstood a challenge without claims being tested.

IPR2025-01060 — Fujirebio Diagnostics, Inc. v. Quanterix Corp

• Type: Inter Partes Review
• Filed: 2025-05-28
• Status: Discretionary Denial – The Patent Trial and Appeal Board (PTAB) declined to institute the inter partes review.
• Judge panel: The specific judge panel for this discretionary denial is not publicly available from the search results. However, an October 17, 2025, memorandum from USPTO Director John Squires indicated that the Director would personally make all institution determinations in IPR and PGR cases, often issuing "summary notices" without written explanations of the reasoning for routine decisions. The last modification date for this proceeding (2025-11-18) falls after this memorandum.
• Petition grounds: The specific claims challenged, prior art relied upon, and statutory bases (§ 102 / § 103 / § 112) of the petition are not publicly available from the search results.
• Institution decision: Denied. The petition was denied institution on or before 2025-11-18. While the specific reasoning for this particular denial is not available, during the period this IPR was processed, the USPTO Director expanded discretionary denial grounds to limit repeated challenges and address factors such as "settled expectations" (i.e., patents in force for several years) and "roadmapping" (i.e., prior challenges to the same patent by unrelated parties), as well as expanded Fintiv factors for parallel litigation.
• Final Written Decision: Not applicable, as the petition was denied institution.
• Settlement / termination: Not applicable.
• Appeal: Not applicable, as there was no Final Written Decision to appeal.
• Defensive value: The patent owner successfully defended against this IPR petition at the institution stage. This means the claims of US11275092 were not subjected to a full trial on their merits before the PTAB in this proceeding, thereby maintaining their presumed validity against the grounds raised in this petition. Any future petitioner would need to present different, compelling grounds or arguments to overcome the discretionary denial policies in place.

Strategic summary

Currently, all claims of US11275092 remain UNTESTED and SUSTAINED by the PTAB, as the sole IPR petition filed against the patent, IPR2025-01060, was denied institution. This means no claims were canceled, nor were any explicitly held patentable in a Final Written Decision, as the trial itself never commenced. The patent, therefore, has not been narrowed through PTAB proceedings.

Regarding the estoppel landscape, since IPR2025-01060 was denied institution, no statutory estoppel under 35 U.S.C. § 315(e)(1) or (2) applies to the petitioner, Fujirebio Diagnostics, Inc., or its privies. This is because estoppel only attaches upon the issuance of a Final Written Decision. Consequently, a new defendant being asserted against is not barred by this particular proceeding from raising any prior-art grounds, including those that might have been raised in IPR2025-01060. The full range of prior-art grounds remains available for potential challenges by other parties.

The status of "Discretionary Denial" for IPR2025-01060 aligns with a broader policy shift observed at the PTAB during 2025, where the USPTO Director began to personally make institution determinations and expanded the grounds for discretionary denials, often issuing summary notices. This signals that the patent owner, Quanterix Corp, effectively leveraged these policies to prevent the institution of a trial. There is no pattern of multiple IPRs from the same petitioner or aggressive PTAB appeals by the patent owner based on the provided data.

Recommended next steps

Given that IPR2025-01060 was denied institution and no claims of US11275092 were invalidated:

• There are no invalidated claims to link to an FWD for this patent. All claims of US11275092 remain valid as far as PTAB proceedings are concerned.
• No active proceedings are currently pending for US11275092.
• The absence of further PTAB activity on this patent, despite the existence of one denied IPR, indicates that potential challengers may find it difficult to obtain institution, possibly due to the nature of the claims or the current discretionary denial policies at the PTAB. However, the patent has not been subjected to a full validity challenge, leaving open the possibility of future, well-crafted petitions on different grounds or by petitioners not affected by the specific discretionary denial grounds of IPR2025-01060.