Written by: Nitai Sylvetsky, Caleb Gilliam-Scott
For many US patent applicants, prosecution can become protracted, with repeated rejections that are difficult to overcome. This occurs often in new software-related technologies, including artificial intelligence (AI) and machine-learning (ML), where the law (35 U.S.C § 101) is not completely settled and open to interpretation.
The Patent Trial and Appeal Board (PTAB) offers a powerful tool to correct an Examiner mistakes: an impartial review by administrative patent judges. While appeals can be effective, success requires careful preparation and strategic timing.
This article outlines key considerations for deploying appeals effectively in complex patent prosecution cases. Many of the strategies discussed below were used in one recent instance handled by our firm. In Ex Parte Ur et al., Appeal No. 2025-003143, the PTAB reversed a 35 U.S.C. § 101 rejection of a machine-learning related invention for routing data transfers across a computer network, after the Examiner had repeatedly maintained that the claims were directed to nothing more than an abstract idea. The Board agreed that the Examiner had improperly read limitations from the specification into the claims and that the claimed invention improved the underlying data-routing technology—thereby integrating any alleged abstract idea into a practical application. That result came after our patent prosecution attorneys used several strategies discussed below that make appeals effective, including filing continuations-in-part to further describe the invention, amending the claims prior to appeal, and providing well-developed arguments focused on the Examiner’s legal error.
- Get the Claims Into Appealable Condition
Because an appeal can be costly, it is generally helpful to refine the claims beforehand. Amendments made with the anticipated appeal arguments and counterarguments in mind may address weaknesses in preceding stages, and reduce the likelihood that the PTAB will affirm on grounds that could have been resolved during prosecution.
In practice, this means, before appeal:
- Clean up antecedent basis, clarity, and 35 U.S.C § 112 issues.
- Ensure claim scope supports the intended appeal arguments.
- Ensure dependent claims were properly amended.
- Remove limitations added in an effort to overcome Examiner rejections but which failed to do so.
Improving the claims pre-appeal will require one additional round with the Examiner (e.g., via Request for Continued Examination (RCE) or interview) which of course may eliminate the need for appeal.
Practical takeaway:
Claims that are clear, internally consistent, and aligned with the intended appeal arguments generally provide a stronger basis for appeal.
- Consider Pre-Appeal Strategy and Prosecution Options
Under USPTO rules, an appeal may be filed once claims have been “twice rejected.” At that point, applicants typically choose between continued prosecution (e.g., RCE) and appeal.
Strategically, it is often worth asking before appeal:
- Can one more amendment materially strengthen the record/arguments?
- Can the Examiner be persuaded through interview or targeted amendment?
- Use Continuation-in-Part (CIP) Filings Strategically
In some cases—particularly where specification support is thin or where claim scope needs meaningful refinement—a continuation-in-part (CIP) application may be appropriate before appealing or in parallel to an appeal.
This may be particularly relevant in 35 U.S.C. § 101 cases without prior-art rejections. Additional technical detail or implementation specificity may support eligibility arguments, provide a basis for revised claims, or better document a technological improvement. A CIP may also be useful where an Examiner has suggested claim amendments that are not adequately supported by the existing specification. Practitioners should, however, consider the tradeoff: new matter may receive a later priority date.
A later priority date may make additional prior art relevant, although that concern may be less significant where the application currently faces only a 35 U.S.C. § 101 rejection.
While a CIP can strengthen 35 U.S.C § 101 arguments, it may complicate 35 U.S.C §102/103 exposure if prior art later emerges.
Practical takeaway:
Use CIPs selectively—primarily where additional disclosure significantly improves substantive patentability, and where prior art risk is manageable.
- Focus on Examiner Error—Preferably Legal Error
An appeal is not simply a “second opinion.” It is a legal review of the Examiner’s rejection.
Effective appeals generally do more than assert that the claimed invention is patentable. They identify a specific error in the rejection, explain the applicable legal or factual issue, and show where the Examiner’s analysis is deficient.
USPTO guidance emphasizes that appeal arguments must directly address Examiner reasoning and show why it is incorrect.
Common successful arguments include:
- Improper claim interpretation, claim construction errors
- Failure to establish a prima facie case, burden not met
- Conclusory obviousness reasoning lacking required legal underpinning
- Misreading or mischaracterizing prior art disclosures
- Improper application of 35 U.S.C § 101 rejections, or ignoring “something more” or “practical application” in 35 U.S.C § 101 cases
Notably, the Examiner bears the initial burden of establishing unpatentability; the applicant need not prove patentability absent a proper prima facie case.
Practical takeaway:
Frame appeal arguments around identifiable errors in the rejection. Specific legal and factual deficiencies are generally more useful than broad assertions about the invention’s merits.
- Draft the Appeal Brief With Precision
The appeal brief is the central advocacy document.
The appeal brief should address each rejection, including the material components of each rejection, because arguments not presented may be treated as waived. This does not require emphasizing weaker points, but it does require ensuring that each ground and relevant sub-issue is addressed. The Manual of Patent Examining Procedure (MPEP) notes that unaddressed grounds may be summarily sustained by the Board.
Key best practices include:
- Focus on or lead with the strongest arguments—weak arguments may dilute them; but ensure all Examiner rejections are addressed.
- Explain possibly ambiguous claim terms and if needed explain why the Examiner’s interpretation is unreasonable.
- Address every ground of rejection explicitly.
A well-structured brief can assist the Board by organizing the issues and arguments in a manner consistent with the framework typically used in PTAB decisions.
- Consider Oral Argument
An oral argument is an opportunity to allow the PTAB to ask you questions. A typical PTAB oral argument includes the PTAB interrupting the attorney’s argument to ask questions; these questions may be based on some misunderstanding or need for clarification on the part of the PTAB (e.g. the meaning of a claim term that might be clear to the Applicant and attorney, but not to “outsiders”). The hearing may therefore provide an opportunity to clarify the written arguments and address concerns that were not apparent from the briefing. Without the oral argument, you may not present important information to the PTAB, because you will not know what the PTAB is asking.
An oral argument requires additional attorney preparation and can significantly increase cost, particularly where an in-person appearance is required. It is not required in every appeal, and applicants should consider whether the likely benefit justifies the added expense in the particular case.
Conclusion
PTAB appeals may provide a path forward after repeated Examiner rejections, but their cost and procedural requirements favor a considered approach. Factors that may improve the prospects of an appeal include:
- Claims refined for clarity, coherence and defensibility
- Arguments focused on specific Examiner errors—especially legal errors in the outstanding Office Action.
- Careful consideration of alternatives to appeal, including additional prosecution or CIP filings (which may be a lead-up to a later appeal)
In short, don’t give up—but don’t appeal prematurely. With appropriate preparation, an appeal can be an effective step toward allowance.
References:
- Ex parte Ur et al., Appeal No. 2025-003143, U.S. Appl. No. 18/220,124 (PTAB June 26, 2026). Accessible via https://data.uspto.gov/ptab/appeals
- United States Patent and Trademark Office (USPTO). (2026). Manual of Patent Examining Procedure (MPEP), Chapter 1200 – Appeal (including §§ 1200, 1205, 1206). Available at: https://www.uspto.gov/web/offices/pac/mpep/mpep-1200.html
- United States Patent and Trademark Office (USPTO). (available July 2026). Appeals explanation. Available at: https://www.uspto.gov/patents/ptab/appeals
United States Patent and Trademark Office (USPTO). (available July 2026). Practice Tips for Writing Effective Appeal Briefs. Available at: https://www.uspto.gov/patents/ptab/procedures/practice-tips-writing-effective
