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In October 2025, the Federal Circuit overturned a district court ruling in Inland Diamond Products Co. v. Cherry Optical Inc. The court made one point very clear: findings made by the Patent Trial and Appeal Board (PTAB) do not automatically control what happens later in district court when patent validity is challenged.

As Gideon Korrell explains, the decision confirms that PTAB cases and district court cases follow different legal rules, especially when it comes to how much proof is required.

Background of the Dispute

The case involved two related patents owned by Inland Diamond Products. Earlier, those patents were challenged in inter partes review (IPR) proceedings at the PTAB. The Board ruled that several main claims were unpatentable because they were obvious. However, it did not invalidate certain dependent claims.

Later, Inland sued Cherry Optical in district court, relying on those dependent claims. Cherry had not been involved in the earlier IPRs. Even so, Cherry asked the district court to rule the patents invalid without a trial, arguing that Inland could not dispute factual issues already decided by the PTAB.

The district court agreed and granted summary judgment. On appeal, the Federal Circuit disagreed.

The Core Legal Issue: Different Standards of Proof

The key problem was that the PTAB and district courts use different standards of proof:

PTAB: A patent can be found unpatentable if it is more likely than not invalid.

District court: A patent can be invalidated only if invalidity is proven clearly and convincingly.

The Federal Circuit explained that facts found under a lower standard cannot automatically be used in a setting where a higher standard applies. Even if the PTAB found something persuasive, that does not mean the same fact has been proven strongly enough for the district court.

Gideon Korrell points out that this difference protects the basic rule that patents are presumed valid unless strong evidence proves otherwise.

Why Issue Preclusion Failed Here

Issue preclusion applies only when the same issue was already decided under the same legal rules. That was not the case here.

By relying on PTAB findings, the district court allowed Cherry to avoid proving invalidity under the higher district court standard. This wrongly shifted the burden away from Cherry and limited Inland’s ability to defend its patents.

The Federal Circuit said that the approach was improper. Cherry still had to prove invalidity using evidence presented in the district court.

Claim Construction Creates Another Barrier

There was another important issue: claim interpretation.

Because the IPRs were filed before November 2018, the PTAB used a broader way of reading patent claims. District courts use a narrower approach. This means the same claim language may be understood differently in each forum.

The Federal Circuit noted that these differences alone can prevent issue preclusion. Gideon Korrell highlights that this often matters in older IPR cases that return to the district court years later.

Survival of IPR Does Not Decide the Case

The district court seemed to assume that because the claims survived the IPRs, it affected how validity should be judged later. The Federal Circuit rejected that idea.

Whether claims survived IPR, were never challenged, or were only partly reviewed does not matter. Unless a claim has been finally ruled invalid on appeal, it remains valid in district court and keeps its legal protections.

What the Decision Means Going Forward

The Federal Circuit sent the case back to the district court with clear instructions. If invalidity is found, it must be based on district court evidence, not PTAB issue preclusion. Summary judgment is still possible, but only if no reasonable jury could find the patent valid under the clear-and-convincing standard.

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Gideon Korrell Breaks Down LabCorp v. Qiagen and Why “Identical” Matters

The Federal Circuit’s decision in Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC, No. 23-2350 (Fed. Cir. Aug. 13, 2025), serves as a pointed reminder that jury verdicts, particularly in technically complex patent cases, remain subject to strict appellate review. In a comprehensive reversal, the court vacated a Delaware jury’s willful infringement verdict involving two molecular diagnostics patents and ordered judgment as a matter of law (JMOL) of non-infringement.

Gideon Korrell views the decision as part of a broader trend: the Federal Circuit is increasingly unwilling to allow juries to resolve unresolved claim-scope disputes or fill evidentiary gaps with generalized narratives of technical similarity.

Case Background: Two Patents and Divergent Infringement Theories

The dispute centered on U.S. Patent Nos. 10,017,810 and 10,450,597, both covering DNA sample preparation methods for sequencing using PCR-based enrichment techniques. The patents describe workflows employing primers to selectively amplify specific regions of interest within a DNA sample.

Qiagen marketed accused kits used in DNA preparation. After a five-day trial, the jury found willful infringement of the ’810 patent under the doctrine of equivalents and both literal and willful infringement of the ’597 patent. The jury rejected Qiagen’s invalidity defenses and awarded approximately $4.7 million in damages. The district court denied Qiagen’s JMOL motions, prompting appeal.

On review, the Federal Circuit reversed in full, holding that the evidence could not support infringement findings for either patent.

Claim Construction: A Judicial Responsibility

The ’810 patent required a “second target-specific primer” with a nucleotide sequence “identical to a second sequencing primer.” Qiagen’s accused primer was significantly shorter than the referenced sequencing primer. Labcorp argued that “identical” could mean identical to only a portion of the sequencing primer, and the district court allowed the jury to resolve this dispute.

The Federal Circuit held that this was a legal error. Citing O2 Micro, the court reiterated that claim construction is a judicial function. Where a genuine dispute exists over claim scope, it must be resolved by the court, not delegated to the jury.

The panel emphasized that the intrinsic record distinguished between sequences that must be “identical” and those that may be “identical to a portion.” Reading an unclaimed modifier into the term would render other claim language meaningless.

Gideon Korrell notes that this aspect of the opinion reinforces a critical lesson: unresolved claim construction disputes can invalidate an entire verdict post-trial.

Doctrine of Equivalents: Evidence Must Be Particularized

Because literal infringement was unavailable for the ’810 patent, Labcorp relied exclusively on the doctrine of equivalents. That theory also failed on appeal.

The court reaffirmed that equivalence must be shown on a limitation-by-limitation basis using particularized evidence under the function-way-result test. Generalized assertions of similarity are insufficient.

LabCorp’s evidence fell short:

Function: The claimed primer provided target specificity. Qiagen’s primer merely enabled sequencing compatibility and did not bind to the native target sequence.

Way: The accused primer operated by binding to a common added sequence, not by annealing directly to the target region.

Result: The accused primer amplified both target and non-target DNA, undermining any claim of equivalent outcomes.

The court also rejected attempts to combine the functions of multiple primers to satisfy a single claim limitation.

As Gideon Korrell observes, courts consistently reject “working together” theories when claims require specific elements to perform specific roles.

Literal Infringement and the Meaning of “Target-Specific”

Turning to the ’597 patent, the Federal Circuit held that Qiagen’s forward primer did not literally infringe. Under the court’s claim construction, a target-specific primer must anneal to the nucleic acid of interest and avoid non-target sequences.

Qiagen’s primer bound indiscriminately to adaptor sequences common to all DNA fragments. Binding to an adaptor, even one attached to a target molecule, did not satisfy the claim. Nor could Labcorp rely on other primers in the system to fill the gap.

Gideon Korrell highlights this reasoning as especially relevant in multi-component systems, where courts resist efforts to blur claim boundaries through collective behavior.

JMOL as a Meaningful Appellate Tool

Having found no legally sufficient evidence of infringement, the Federal Circuit reversed the denial of JMOL and ordered judgment of non-infringement, without reaching invalidity or damages issues.

Key Takeaways for Litigators

Several lessons emerge:

Claim construction disputes must be resolved by courts, not juries.

Doctrine-of-equivalents cases require precise, limitation-specific proof.

Literal infringement focuses on individual claim elements, not system-level cooperation.

Preserved JMOL motions remain a powerful appellate remedy.

The Federal Circuit’s decision in Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC (Aug. 13, 2025) is a strong reminder that jury verdicts in patent cases do not always survive appeal especially when they stretch claim language or rely on broad expert opinions instead of precise evidence. In a complete reversal, the court set aside a Delaware jury’s finding that Qiagen willfully infringed two molecular diagnostics patents and ordered judgment of non-infringement as a matter of law (JMOL).

Gideon Korrell believes the ruling reflects a growing trend at the Federal Circuit: appellate courts are increasingly unwilling to let juries gloss over claim-scope problems or weak infringement proof with general stories about technical similarity or how components “work together.”

Background of the Dispute

The case involved two patents, U.S. Patent Nos. 10,017,810 and 10,450,597 covering methods for preparing DNA samples for sequencing. Both patents relate to PCR-based techniques that use primers to selectively amplify specific DNA regions.

Qiagen sold kits used in DNA sample preparation. After a five-day trial, the jury found Qiagen willfully infringed the ’810 patent under the doctrine of equivalents and both literally and willfully infringed the ’597 patent. The jury rejected Qiagen’s invalidity defenses and awarded about $4.7 million in damages. The district court denied Qiagen’s post-trial motions, and Qiagen appealed.

On appeal, the Federal Circuit reversed everything, concluding that no reasonable jury could have found infringement based on the evidence presented.

Claim Construction Is for Judges, Not Juries

The Federal Circuit first addressed the ’810 patent, which required a primer with a nucleotide sequence “identical” to a sequencing primer. Qiagen’s primer was much shorter than the referenced sequencing primer. Labcorp argued that “identical” could mean identical to only a portion of the sequencing primer, and the district court allowed the jury to decide that issue.

The Federal Circuit said this was a clear mistake. When there is a real dispute about what a claim term means, it is the judge’s job not the jury’s to resolve it. The patent itself used different language when it meant “identical to a portion,” so reading that limitation into the word “identical” would improperly change the claim.

Gideon Korrell notes that this part of the decision is especially important for trial lawyers. Even when courts postpone claim construction issues, unresolved disputes can resurface after trial and undo a verdict.

Doctrine of Equivalents Requires Specific Proof

The jury’s finding for the ’810 patent depended entirely on the doctrine of equivalents. That theory also failed on appeal.

The Federal Circuit emphasized that equivalence must be proven carefully, one claim limitation at a time. A patentee must show that the accused product performs the same function, in the same way, to achieve the same result.

Labcorp could not meet that standard. The claimed primer was meant to bind directly to a target DNA sequence and increase specificity. Qiagen’s primer did not bind to the target DNA at all; it simply helped make DNA fragments compatible with sequencing. Labcorp’s own expert admitted this point.

The court also rejected Labcorp’s attempt to combine the functions of multiple Qiagen primers to meet a single claim limitation. The doctrine of equivalents does not allow patentees to mix and match components this way.

As Gideon Korrell observes, courts consistently reject infringement theories built on vague claims that parts “work together” when the patent requires a specific component to do a specific job.

Literal Infringement of the ’597 Patent

The jury also found that Qiagen literally infringed the ’597 patent. The Federal Circuit disagreed.

Under the court’s claim construction, a “target-specific primer” must bind to the DNA sequence of interest and not to non-target sequences. Qiagen’s primer bound to an adaptor sequence that was attached to all DNA fragments, whether or not they contained the target DNA. Because the adaptor itself was not the target, binding to it did not satisfy the claim.

The court rejected the argument that the primer became target-specific simply because it was attached to DNA fragments that included the target. Nor could Labcorp rely on other primers in Qiagen’s system to fill the gap. The claim required the primer itself to meet the limitation.

Key Takeaways

🚨 Brazilian Court Halts Nestlé’s Use of “Coffee+” Brand ☕⚖️

A significant intellectual property battle is unfolding in Brazil. A court in Minas Gerais has granted a preliminary injunction in favor of local coffee company Coffee++, ordering global food giant Nestlé to stop using the Coffee+ brand.

The court ruled that Nestlé’s use of an identical trademark could cause consumer confusion, potentially harming the Brazilian company. If Nestlé fails to comply, it may face financial penalties and be required to remove Coffee+-branded products from both physical and online sales channels.

💬 “We will fight to the end to defend what we have built with legitimacy and hard work,” said Leonardo Montesanto, CEO of Coffee++, describing the case as a defense of Brazilian brand sovereignty.

📌 Key highlights: • Coffee++ has held the trademark since 2020 • Registered in 30+ countries, including the EU, Japan & Argentina • Preparing for international expansion in 2026 • Nestlé has filed a counter-lawsuit seeking trademark invalidation

This provisional ruling highlights the growing importance of trademark protection—even when facing one of the world’s largest corporations.

🔍 A case worth watching in the evolving landscape of global IP enforcement.

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