PTAB challenges

Proceedings overview

One Post-Grant Review (PGR) proceeding has been filed against US patent 12174107. The PGR was denied institution on procedural grounds, meaning no claims were invalidated. This gives a defendant a posture where the patent has not been challenged on its merits at the PTAB, but the specific grounds raised in the petition for PGR2025-00088 cannot be raised again by the same petitioner or their privies.

PGR2025-00088 — Cytek Biosciences, Inc. v. Beckman Coulter, Inc.

• Type: Post-Grant Review
• Filed: 2025-09-23
• Status: Discretionary Denial (Institution denied on procedural grounds due to ongoing parallel district court litigation).
• Judge panel: Not publicly available in the provided information, but Jeffrey N. Fredman and John G. New are known PTAB judges with activity in PGRs around this time.
• Petition grounds: The petition challenged the validity of claims of U.S. Patent No. 12,174,107. The Patent Owner's request for discretionary denial specifically mentions that the Petitioner's arguments from this PGR were incorporated into its § 112 contentions in the district court.
• Institution decision: Denied on 2026-03-17. The PTAB denied institution based on discretionary considerations under 35 U.S.C. § 314(a), citing the advanced stage of a parallel district court litigation where a jury trial is scheduled for August 17, 2026, which is more than five months before the PTAB's projected final written decision deadline of January 2027. The district court had previously denied requests to adjourn the trial. The PTAB's decision aligns with its policy to deny institution when a parallel district court proceeding is likely to reach a final decision on patentability before the PTAB.
• Final Written Decision: Not issued, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: No appeal of a Final Written Decision, as none was issued.
• Defensive value: The patent claims were not reviewed on their merits by the PTAB in this proceeding. However, Cytek Biosciences, Inc. (and its privies) are estopped from raising the same invalidity grounds (and any grounds that could have been raised) from this petition in future PTAB proceedings. For other potential defendants, the patent claims remain untested at the PTAB, but the arguments regarding the proximity of a district court trial may provide a precedent for discretionary denial if similar circumstances arise.

Strategic summary

Only one PGR, PGR2025-00088, has been filed against US patent 12174107 by Cytek Biosciences, Inc. The petition was denied institution on procedural grounds, specifically due to the ongoing parallel district court litigation with a jury trial scheduled for August 17, 2026. This means that no claims of 12174107 have been formally challenged or invalidated by the PTAB.

For a defendant currently facing assertion of this patent, the patent claims are still considered "untested" in terms of a merits-based PTAB review. The denial of institution in PGR2025-00088 was a discretionary decision based on the advanced stage of the district court case. This scenario highlights the PTAB's discretion to deny institution under certain circumstances to avoid duplicative efforts with district court litigation.

Regarding estoppel, Cytek Biosciences, Inc. (and any parties in privy with them) would be estopped under 35 U.S.C. § 315(e)(2) from re-raising any ground that was raised or reasonably could have been raised in the PGR petition in future PTAB proceedings against patent 12174107. Other potential petitioners would not be estopped by this denial from challenging the patent on different grounds or even the same grounds if they are not in privy with Cytek. The patent owner, Beckman Coulter, Inc., has successfully fended off this initial PTAB challenge, but the validity of the claims on the merits has not yet been adjudicated by the PTAB.

Recommended next steps

If you are a defendant facing assertion of US patent 12174107, be aware that while a PGR was filed, institution was denied on procedural grounds. Therefore, no claims have been invalidated. Cytek Biosciences, Inc. is estopped from re-raising the grounds presented in PGR2025-00088. Other potential petitioners are not bound by this estoppel.

The district court jury trial for the parallel litigation (1:24-cv-00945 in the U.S. District Court for the District of Delaware) is scheduled for August 17, 2026. The outcome of this trial will be highly significant. Consider monitoring this district court case closely as it may provide insights into the strength of the patent and potential invalidity arguments.

The absence of any PTAB activity where claims were addressed on their merits means that the patent's claims remain a live issue in litigation.