Third-Party Observations at the EPO: A Simple and Cost-Effective Tool, But Use It Wisely

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Last month, the European Patent Office (EPO) issued a notice[1] on the processing of third-party observations (TPOs) and the new online form for filing them. This is a good opportunity to review the key principles of TPOs and their potential effects, both positive and negative.

In essence, TPOs allow anyone to submit comments on a pending patent application to influence the EPO's decision regarding the application. According to the EPO, "Such observations serve the public interest by […] increasing the likelihood that only solid and robust patents are granted." In other words, the EPO welcomes external input to ensure that only legally sound patents are granted.

What's New?

The EPO has introduced a new online form for filing TPOs. While the changes are modest, the new form is more user-friendly than its predecessor. Using the online form is recommended, but not compulsory. The online form is designed to encourage concise and reasoned observations which can be quickly understood and evaluated by EPO examiners[2].

The EPO's notice also clarifies, using practical examples, how TPOs filed with the International Bureau against a PCT application during the international phase are treated by the EPO in the subsequent European regional phase.

Key Principles of Third-Party Observations

There is no official fee for filing TPOs with the EPO.

TPOs can be filed against a published European patent application at any time before the decision to grant is taken by the EPO, though ideally as early as possible. They can also be filed against granted European patents during opposition proceedings. TPOs should concern substantive requirements such as novelty, inventive step, clarity, or added subject matter (not formal aspects).

TPOs may be filed anonymously. They should be submitted in English, French, or German. Supporting documents, such as prior art citations, can be in any language, though the EPO may request a translation. TPOs become part of the public file of the application or patent, which means that they will be accessible to anyone.

The EPO examiner will promptly forward the TPOs to the applicant who filed the patent application. The applicant may comment on them. The examiner must consider the TPOs and comment on their relevance in the next substantive communication. If the TPOs are substantiated and not anonymous, the examiner will aim to issue the next communication within three months of receiving the TPOs. If a reply from the applicant is outstanding when the TPOs are received, the three-month period starts from receipt of that reply.

Third parties filing TPOs are not parties to the proceedings and so will not be informed directly by the EPO or be further involved in proceedings. They cannot argue their position or appeal if the EPO examiner does not adequately consider their observations. However, to mitigate these drawbacks, they can monitor the proceedings online and file multiple TPOs.

Strategic Considerations

Compared to opposition proceedings before the EPO or revocation actions before a Court (i.e., a national Court or the Unified Patent Court), TPOs are far less expensive. They offer a fast and cost-effective way to challenge a European patent application and try to avoid its grant or at least narrow its scope. Further, substantiated and non-anonymous TPOs can accelerate examination proceedings, thereby reducing the period during which the existence and scope of the patent rights remain uncertain.

However, the effectiveness of TPOs depends entirely on how the EPO examiner evaluates them. More importantly, even when filed anonymously, TPOs alert the applicant that their patent application has attracted attention and that post-grant challenges may follow. This can prompt the applicant to strengthen their position: for example, by strategically amending claims, filing divisional applications, or validating the European patent in more countries than initially foreseen.

The Bottom Line

Third-party observations are a simple and cost-effectivetool, but they should be deployed thoughtfully. Consider both the potential benefits and the risk of alerting your competitor to take defensive measures.

If you have questions about whether filing third-party observations makes sense for your situation, we're here to help.