Secondary Considerations in Patent Validity Challenges: Understanding Their Role in IPR and District Court Litigation

1. Secondary considerations are critical in both IPR and district court for establishing nonobviousness.
   
   
2. Strong documentary evidence and expert testimony are essential.
   
   
3. The nexus requirement is pivotal; success must be tied directly to the claimed invention
   
   
4.  PTAB proceedings rely on written, technical records, while district courts allow broader evidence and live testimony.

Setting the Stage: The Role of Secondary Considerations in Patent Validity

When a patent faces an obviousness challenge under 35 U.S.C. §103, secondary considerations often play a pivotal role in defending its validity. These real-world indicators, such as commercial success, industry praise, and long felt but unsolved needs, provide compelling evidence that an invention was not obvious to those skilled in the art.

Both the Patent Trial and Appeal Board (PTAB) and district courts must consider secondary considerations as part of the obviousness analysis. Understanding how they are treated in inter partes review (IPR), district court litigation, and ex parte reexamination (EPR) is essential for both patent owners and challengers.  

Scope Note: This article focuses on how secondary considerations (also known as objective indicia) operate in obviousness analyses before the PTAB in IPR proceedings and in federal district court litigation. They are also relevant in ex parte reexamination at the USPTO, where they are presented to an examiner rather than to administrative judges. Although the same legal principles apply, ex parte reexamination follows PTO examination procedures rather than IPR or judicial standards.

The Graham Framework

The framework for evaluating obviousness originates from Graham v. John Deere Co. of Kansas City, 383 U.S. 1 (1966) and the PTAB apply four factors in determining whether a claim is obvious:

1. The scope and content of the prior art.
2. The differences between the prior art and the claimed invention.
3. The level of ordinary skill in the art.
4. Secondary considerations.

Secondary considerations—such as commercial success, long felt but unsolved need, failure of others, industry praise, copying by competitors, and unexpected results—ground the obviousness inquiry in real-world evidence. They guard against hindsight bias and help demonstrate the inventive step in context.

Common Secondary Considerations

Courts and the USPTO have recognized the following as secondary considerations (objective indicia):

• Commercial success of the invention or products embodying the invention
• Long felt but unsolved need addressed by the invention
• Failure of others to solve the problem
• Unexpected results or properties
• Industry praise or recognition
• Copying by competitors
• Licensing of the patent or invention
• Skepticism before the invention’s success
• Displacement of prior art devices or methods
• Acceptance by others in the field
• Industry adoption or widespread use
• Professional or scientific awards
• Customer demand or market share
• Evidence of teaching away in the prior art

Not every case involves all these factors, but each can provide compelling, real world evidence that the invention was not obvious.

Establishing and Applying the Nexus Requirement

A nexus must be established between the evidence and the claimed invention. The nexus ensures that success or recognition stems from the patented features, not from unrelated factors such as marketing or pricing.

Presumption of Nexus

The presumption of nexus for secondary considerations applies only when the patent owner demonstrates that the product or process embodying the claimed invention is coextensive with the scope of the claims. Coextensiveness means that the product’s relevant features are substantially the same as those claimed, and that the objective evidence (such as commercial success, long-felt need, licensing, or industry praise) is tied directly to the claimed invention. If coextensiveness is established, the burden shifts to the challenger to rebut the presumption by showing that the secondary considerations are attributable to something other than the claimed invention, such as marketing efforts or unclaimed features. If coextensiveness is not present, no presumption arises, and the patent owner must affirmatively prove nexus by showing that the secondary considerations result from the unique characteristics of the claimed invention. This framework is reflected in Federal Circuit precedent and the Manual of Patent Examining Procedure (MPEP) § 716.01(b).

While Graham acknowledged the importance of secondary considerations, it did not establish a requirement that commercial success or other indicia be directly tied to the claimed invention. That principle—the nexus requirement—was later developed by subsequent caselaw[1]. When a commercial product is coextensive with the claimed invention, a rebuttable presumption arises its success or praise is due to the claimed features. This presumption can be rebutted by showing that unclaimed features or external factors drove the success.

Examples:

• Medical Device: A patented medical device embodying all claimed features enjoys a strong presumption that commercial success and industry praise derive from the invention. If, however, success stems from unclaimed elements (such as a unique display or software), a challenger can rebut the presumption.
• Chemical Composition: A patented chemical composition showing unexpected performance results supports a strong presumption of nexus, but that presumption can be rebutted if market success results from aggressive marketing or lower pricing.
• Electrical Engineering: A patented microprocessor architecture that embodies all claimed features and achieves industry recognition benefits from a presumption of nexus. That presumption can be rebutted if success is due to unclaimed modules or software compatibility.

Patent owners should support nexus with detailed technical and market evidence, while challengers may seek to disconnect the objective indicta from the claimed features.

Secondary Considerations in Different Forums

A. PTAB (Inter Partes Review)

At the PTAB, secondary considerations typically appear during the trial phase after institution. Patent owners present them in the Patent Owner Response (POR) to counter the petitioner’s obviousness arguments.

Evidence and Presentation

• • Sales data and market reports showing commercial success
  • Industry recognition, awards, or adoption evidence
  • Expert or inventor declarations linking success to claimed features

Because IPR discovery is limited (mainly declarant depositions), patent owners must build a strong written record.

Key Standards

• • Petitioner bears the ultimate burden to prove unpatentability by a preponderance of the evidence.
  • Patent owner bears a burden of production to submit objective indicia evidence.
  • Once introduced, the Board must weigh all four Graham factors, including any applicable presumption of nexus.

Practical Tips

• • Include secondary considerations in the POR.
  • Provide contemporaneous documentation and expert testimony.
  • Clearly tie the evidence to the claimed features to preserve nexus.

B. District Court Litigation

In district court, secondary considerations often carry significant weight because of broader discovery and the ability to present live testimony.

Evidence and Presentation

• • Secondary considerations are developed during fact and expert discovery: sales data, market analyses, industry praise or copying, and technical reports.
  • Introduced at summary judgment or trial through expert testimony, trial exhibits, and depositions.
  • Live testimony and broader discovery allow a narrative-driven presentation.

Standards

• • Defendant challenging validity must prove obviousness by clear and convincing evidence.
  • Evidence must show that observed success or recognition stems from the claimed invention. The presumption of nexus applies if the product is coextensive with the claimed invention, subject to rebuttal.

Practical Tips

• • Collect quantitative and qualitative evidence early.
  • Prepare detailed expert reports linking technical features to commercial success.
  • Introduce evidence systematically at trial and ensure jury instructions emphasize secondary considerations as integral to the obviousness analysis. See additional note on jury instructions below.
  • Address challenges to nexus proactively, distinguishing claimed features from marketing, pricing, or unclaimed aspects.

Jury Instructions

At trial, juries are instructed to evaluate obviousness under the Graham framework, including objective indicia. Model jury instructions emphasize that secondary considerations are not optional; they must be weighed with the other Graham factors. Jurors are typically told that such evidence of  commercial success, long felt but unsolved need, failure of others, industry praise, copying by competitors, and unexpected results helps guard against hindsight bias and contextualizes the inventive step at the time of invention.

C. Ex Parte Reexamination (EPR)

In ex parte reexamination, the patent owner may submit objective indicia evidence to the examiner to rebut an obviousness rejection, such as commercial success, industry praise, copying, long felt need, and unexpected results.

The USPTO applies a preponderance of the evidence standard under examination procedures. Because the process is paper-driven, a clear, well-documented showing of nexus between the evidence and the claimed invention is critical for the indicia to carry weight.

D. Table Comparison of District Court and PTAB Proceedings

Table Summary

District courts allow a broad range of evidence and live testimony,  often leading to persuasive, narrative-driven presentations. The PTAB applies a more technical, paper-focused approach, with limited discovery and a lower standard of proof. In both forums, the effectiveness of secondary considerations depends heavily on establishing a strong nexus between the evidence and the claimed invention.

Note on forum standards: district courts apply a clear and convincing standard to invalidity; the PTAB applies a preponderance standard in IPR; the PTO also applies a preponderance standard during ex parte reexamination as part of examination practice.

Patent Owner and Challenger Strategic Perspectives

Patent Owner Strategies

• Develop secondary considerations early in the case.
• Gather quantitative and qualitative evidence—sales data, customer demand, awards, expert declarations.
• Explicitly connect success to claimed features, not marketing or unclaimed attributes.
• When applicable, invoke and substantiate the presumption of nexus.

Challenger Strategies

• Rebut nexus by showing success stems from unclaimed features, marketing, or pricing.
• Use expert analysis and market data to disconnect objective indicia from the claimed invention.
• Emphasize the absence of coextensiveness when challenging presumption of nexus.

Conclusion: Maximizing the Impact of Secondary Considerations

Secondary considerations offer a powerful means of grounding patent validity in real-world evidence, protecting against hindsight, and emphasizing the practical value of innovation. Whether before the PTAB, in district court, or during ex parte reexamination, success turns on the same principle: the ability to clearly connect evidence of market or technical achievement to the specific features claimed in the patent.

In short, objective indicia must tell the invention’s story—and that story must trace directly to the claims.

Third Party EPR Challenger Perspective:

A third party challenger in ex parte reexamination can address the presumption of nexus by presenting evidence that the product’s success, industry praise, or other objective indicia are actually due to features not claimed in the patent, or to factors such as marketing, distribution, or pricing. Challengers should carefully analyze the patent owner’s evidence and look for unclaimed elements or external factors that could have contributed to the observed success. By providing technical analysis, market data, or expert testimony that disconnects the objective evidence from the claimed invention, a challenger can rebut the presumption and reduce the persuasive value of secondary considerations. It is important to remember that in EPR, a patent owner may also act as a challenger against another patent, so these strategies are relevant for any party seeking to challenge a patent’s validity.

Patent Owner Perspective

Patent owners can benefit from the presumption of nexus when their product is coextensive with the claimed invention, but they should not rely solely on conclusory statements or general assertions. Instead, patent owners should provide detailed and well documented evidence, such as sales data, expert declarations, technical analysis, and customer or industry feedback, that directly links the objective indicia to the specific features claimed in the patent. This includes demonstrating that the claimed invention, rather than unclaimed features or external factors, is responsible for the commercial success, industry recognition, or other secondary considerations. Patent owners should also be aware that they may sometimes act as an EPR challenger themselves, and in those cases, the same principles for establishing or rebutting nexus will apply. Ultimately, a strong, fact based showing of nexus is essential to maximize the impact of secondary considerations in any forum.

Endnotes

[1] Manual of Patent Examining Procedure §716.01(b) (9th ed. Nov. 2013)) (“Note the great reliance apparently placed on [evidence of secondary considerations] by the Supreme Court in upholding the patent in United States v. Adams, 383 U.S. 39, 148 U.S.P.Q. 479 (1966) [the companion case to Graham v. John Deere Co.]… The term ‘nexus’ designates a factually and legally sufficient connection between the objective evidence of nonobviousness and the claimed invention so that the evidence is of probative value in the determination of nonobviousness.”