USPTO to PTAB: ‘Explain Yourself'

October 17, 2025

On September 16, 2025, the U.S. Patent and Trademark Office issued a memorandum that will reverberate across the patent litigation landscape. For the first time, the PTAB is being directed to reckon with prior adjudications in a meaningful, legally accountable way. When a district court, the ITC, or another USPTO tribunal has already weighed in on the validity or patentability of substantially similar claims, the Board may no longer brush that aside with a nod to “different burdens of proof.” It must now engage the record, analyze the findings, and explain its divergence.

The memo is brief. Its implications are not. This shift reaches the heart of how the PTAB operates within the ecosystem of overlapping tribunals. For more than a decade, divergence between PTAB and Article III outcomes has been tolerated—sometimes even expected—as the price of parallel adjudication. That era may be coming to an end.

A System Long Defined by Tension

The tension between forums has been baked into the modern post-grant system since its inception. District courts and the ITC apply the clear-and-convincing burden of proof under § 282; the PTAB applies the lower preponderance standard under § 316(e). Courts permit broader discovery and rely on live testimony and cross-examination; PTAB proceedings are streamlined, written, and heavily front-loaded. District court judgments carry preclusive weight; PTAB final written decisions have their own statutory consequences.

Federal Circuit precedent has confirmed that divergent outcomes are permissible. In In re Swanson, 540 F.3d 1368 (Fed. Cir. 2008), the court upheld the USPTO’s ability to revisit validity despite a prior judicial determination. In Fresenius USA, Inc. v. Baxter Int’l, Inc., 721 F.3d 1330 (Fed. Cir. 2013), it held that a PTAB invalidation can override a prior Article III judgment. This structural fragmentation has shaped litigation strategy for years: petitioners often viewed PTAB as a second bite at the apple, and patent owners understood that victory in one forum could not guarantee safety in another.

Until now, the PTAB has treated this divergence as largely self-justifying. The Board routinely cited differing burdens of proof or procedural postures to explain conflicting outcomes in a sentence or two. The September memorandum draws a hard line against that practice. Going forward, divergence must be earned through explanation.

Administrative Law Arrives at the PTAB’s Doorstep

The legal logic behind this development is not novel—it’s administrative law 101. Under Motor Vehicle Manufacturers Ass’n v. State Farm, 463 U.S. 29 (1983), agencies must offer reasoned explanations for their actions, particularly when departing from prior findings or settled evidentiary predicates. FCC v. Fox Television Stations, 556 U.S. 502 (2009), reinforced that an agency must explain a change in position or departure from existing factual baselines.

These principles have long applied to administrative adjudications, but the PTAB has, until now, largely sidestepped them. When the Board invalidated claims that had already survived judicial scrutiny, it did so without much engagement with those prior findings. The memo is an acknowledgment that this posture is increasingly untenable—legally and institutionally.

It requires the PTAB to consider not merely the existence of prior decisions, but the substance of those proceedings: the evidence, the claim constructions, the expert testimony, the underlying legal analysis. If the PTAB reaches a different conclusion on substantially similar records, it must articulate why. The strength of that explanation must scale with the degree of overlap. This is a significant recalibration of the Board’s relationship to the broader adjudicatory system.

A Strategic Rebalancing for Patent Owners

For patent owners, this is a meaningful shift in leverage. A prior district court or ITC finding upholding claim validity is no longer just a persuasive data point—it’s a procedural anchor. Patent owners can now build PTAB strategies around forcing the Board to confront those findings head-on.

The timing of this matters. Raising prior adjudications early—especially in the preliminary response—can force the explanatory burden back onto petitioners and the Board at the institution stage. And if the Board does diverge without sufficient explanation, it opens a clear appellate pathway under the Administrative Procedure Act. In a system where APA challenges have increasingly gained traction at the Federal Circuit (In re Van Os, Arthrex v. Smith & Nephew), this gives patent owners a powerful backstop.

The practical upshot is that prior adjudications now carry more gravitational weight. They shape not only the merits but also the Board’s risk calculus in writing its decision.

A More Demanding Playing Field for Petitioners

For petitioners, the cost of divergence has gone up. Petitions that simply repackage prior art and arguments already rejected in another forum will require the PTAB to explain why it is ignoring someone else’s findings. Petitioners will need to build cleaner, more differentiated records—new prior art, more rigorous expert testimony, or legal theories capable of supporting divergence that can withstand appellate scrutiny.

This may also force more deliberate forum strategy. An adverse district court decision on validity will now cast a longer shadow over a subsequent IPR. Even if the PTAB ultimately disagrees with the court, it must articulate why. A weak petition won’t just lose; it could also generate a decision that is more vulnerable on appeal.

A Larger Agency Realignment

The September memorandum is not an isolated move. It fits into a broader pattern of USPTO recalibration in 2025. The agency has already rescinded the Vidal memo, reopened the door to discretionary denials under Fintiv and Sotera, and sharpened its enforcement of evidentiary standards, including the use of general knowledge and applicant-admitted prior art.

Taken together, these steps reflect a clear trend: the USPTO is exerting greater control over PTAB decision-making. It is pushing the Board toward more coherent, disciplined, and defensible adjudication. This is both a litigation reality and a signal to the Federal Circuit that the agency is taking its APA obligations seriously.

The Cost of Inconsistency Just Went Up

The PTAB remains free to reach different conclusions from other tribunals. What has changed is the price of doing so. The Board must now articulate a reasoned, evidence-based justification that can survive judicial review. For patent owners, this creates new avenues to defend their claims and challenge adverse decisions. For petitioners, it raises the bar for strategic and evidentiary rigor.

This is not a procedural footnote. It is a fundamental shift in the gravitational field of post-grant practice. Divergence is no longer presumed; it must be defended. In high-stakes patent disputes, that single fact could reshape how—and where—validity battles are fought.