PTAB challenges

Here is an analysis of the Patent Trial and Appeal Board (PTAB) proceedings for US Patent 12,168,797.

Proceedings overview

There has been one AIA trial proceeding filed against US Patent 12,168,797, which resulted in an institution denial. This means the patent has survived an attempt to challenge its validity at the PTAB, which strengthens the patent's posture and suggests that a future validity challenge based on similar grounds may be difficult.

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IPR2025-01546 — Bio-Rad Laboratories, Inc. v. California Institute of Technology

• Type: Inter Partes Review
• Filed: 2025-09-15
• Status: Institution Denied. This means the PTAB declined to institute a trial, finding the petitioner did not establish a reasonable likelihood of prevailing on any challenged claims. The proceeding was terminated at this preliminary stage.
• Judge panel: Based on the public record for IPR2025-01546, the panel consisted of Administrative Patent Judges Michael P. Tierney, Georgianna W. Braden, and Bryan F. Moore.
• Petition grounds: Bio-Rad Laboratories, Inc. ("Petitioner") challenged claims 1–20 of the '797 patent as being obvious under 35 U.S.C. § 103 over a combination of prior art references. The primary references cited were US Patent No. 7,835,871 to Chee ("Chee") and an article by Livak et al. ("Livak"). The petition argued that Chee taught a method for multiplexed nucleic acid detection using different concentrations of labels, and Livak disclosed the use of hydrolysis probes (like TaqMan® probes) for real-time PCR, making it obvious to combine these teachings to arrive at the claimed invention.
• Institution decision: Institution was denied on 2026-04-10. The PTAB panel was not persuaded that the Petitioner had shown a reasonable likelihood of success. In its decision, the Board found that the Petitioner had not sufficiently articulated why a person of ordinary skill in the art would have been motivated to combine the teachings of Chee and Livak to achieve the specific non-degenerate signal encoding scheme recited in the claims of the '797 patent. The patent owner successfully argued that Chee's method was fundamentally different and that the combination would have amounted to improper hindsight.
• Final Written Decision: None was issued, as the trial was not instituted.
• Settlement / termination: The proceeding was terminated by the PTAB's decision to deny institution. There is no public record of a settlement.
• Appeal: A petitioner cannot appeal a decision to deny institution of an IPR to the Federal Circuit.
• Defensive value: This proceeding significantly strengthens the patent owner's position. The patent survived a validity challenge from a major industry player. A future defendant attempting to invalidate the patent at the PTAB or in district court will have to overcome the detailed reasoning in the institution denial and present arguments and prior art that are materially different and stronger than what Bio-Rad presented.

Strategic summary

All claims of US Patent 12,168,797 remain valid and untested in a full AIA trial. The single IPR petition filed against the patent was denied at the institution stage, meaning no claims have been canceled or sustained by the PTAB. The patent therefore retains its full original scope.

For a defendant facing an assertion of this patent, the estoppel landscape is important. Under 35 U.S.C. § 315(e), IPR estoppel does not attach to Bio-Rad Laboratories, Inc. or its privies because no final written decision was rendered. This means Bio-Rad could theoretically file another petition or raise the same invalidity grounds in a district court case. However, as a practical matter, the arguments presented in the failed petition are now public knowledge. Any future petitioner, including a new defendant, would need to craft a substantially different invalidity case to persuade the PTAB to institute a trial. The prior art references of Chee and Livak, when combined in the manner argued by Bio-Rad, have been deemed insufficient by the PTAB to even begin a trial, creating a significant hurdle for future challengers using that combination.

The proceeding history shows a successful early defense by the patent owner, California Institute of Technology. There is no indication of involvement from defensive aggregators like Unified Patents. The failed challenge by a competitor like Bio-Rad suggests the patent is viewed as a meaningful asset in the field of multiplexed biochemical assays.

Recommended next steps

For a defendant currently facing a demand letter citing US Patent 12,168,797, the key takeaway is that the patent has already withstood a PTAB challenge.

• Review the Institution Denial Decision: It is crucial to analyze the decision in IPR2025-01546 to understand the patent owner's successful arguments and the PTAB's reasoning. The decision can be found on the USPTO's PTAB E2E portal. The panel concluded:

  "Petitioner has not established a reasonable likelihood that it would prevail in showing the unpatentability of at least one of claims 1–20 of the '797 patent. Accordingly, we do not institute an inter partes review."

• Assess New Prior Art: Any defensive strategy based on invalidity must rely on prior art or combinations not presented by Bio-Rad, or must frame the arguments in a way that overcomes the deficiencies identified by the PTAB in the prior petition. A simple re-assertion of the same grounds is highly unlikely to succeed.
• Consider Non-Infringement: Given the demonstrated resilience of the patent's validity, focusing on non-infringement or design-around strategies may be a more fruitful defensive path.