Ex Parte Reexamination Requests: What Experienced Practitioners Watch For Before Filing

Overview

Ex parte reexamination is often viewed as a cost-efficient alternative to inter partes review. That is correct, but it is also where many otherwise strong validity positions fail at the threshold. The reason is straightforward: the United States Patent and Trademark Office (“USPTO”) will not reach the merits unless the request clearly establishes a “substantial new question of patentability” (“SNQ”). In practice, that requirement is exacting and unforgiving.  If the petition for ex parte reexamination does not carry the burden at filing, the proceeding does not open.

1. The SNQ Requirement and Common Failure Points

Clients and attorneys alike are often surprised to learn that reexamination can be denied without any substantive review of patentability. The USPTO first asks whether the request raises a substantial new question of patentability relative to what was previously considered. If that showing is not made, the request ends there.

A recurring defect is treating the SNQ requirement as a conclusion rather than a demonstration. Statements that a reference “teaches” a limitation, without showing where and how, many do not carry the threshold. An effective request introduces a new reference or combination, and explains how those reference(s) materially would affect examination.

Even strong requests fail on procedural grounds. Identifying each claim, articulating each substantial new question of patentability in the USPTO preferred format, providing copies of references, paying the fee, and serving the patent owner are mandatory requirements.  For example, even if you include a reference in a petition for ex parte reexamination that could establish a substantial new question of patentability, the USPTO may still deny the petition on for ex parte reexamination on procedural grounds IF the petition does not include a statement pointing out each substantial new question of patentability and a detailed explanation of the same. Delaying institution of an ex parte reexaminations can be costly – especially if there is a Motion To Stay district court litigation hinging on the ex parte re examination being granted. 

2. Drafting Discipline: Charts, References, and Rationale

Claim charts are central. Element-by-element mapping, with pinpoint citations, is expected. Requests that rely on generalized descriptions or block quotations may not be effective or clear and may be denied. A claims chart should allow a reviewer to quickly locate where each limitation is disclosed. 

There is also a tendency to include every conceivable reference. That approach dilutes the showing. The Office is not weighing competing theories at this stage; it is determining whether a clear, focused issue exists. A smaller number of well-selected references, each with a defined role, more effective.

Where the request relies on a combination, the rationale must be concrete. Generic statements that it would have been “obvious to combine” are insufficient without support tied to the references or the problem addressed. The rationale should be grounded in recognized frameworks – such as known substitutions or predictable results – and anchored in evidence rather than post hoc reasoning.  For example, pointing to one of the newly cited references for the reasoning as to why it would be obvious to combine a reference is one way to provide evidence that supports the “obvious to combine” reasoning. 

3. Strategic Framing

The objective at filing is to open the proceeding, not to fully litigate the merits. Over-arguing can obscure the SNQ analysis. The most effective requests are structured, evidence-driven submissions that lead with the SNQ and support it with precise mapping.

Ex parte reexamination remains a useful tool where strong printed publications exist and where avoiding estoppel is important. It is particularly effective when the issue can be framed around a discrete limitation or combination that was not previously considered.

4. Timing 

Conclusion

Most denials are not driven by weak prior art, but by imprecise drafting—failure to articulate the SNQ, failure to distinguish the prior record, or failure to map the claims with clarity. When the request is treated as a disciplined, front-loaded submission, the likelihood of institution increases materially.