Patent offices offering third-party observations/submissions generally impose a limit on the number of TPOs than can be filed anonymously. Do PCT TPOs count against this limit?

This article seems to loosely imply it does count:

Moreover, it is only possible to comment on novelty and inventive step [in a PCT TPO]. Third parties may therefore prefer to wait until national/regional phase proceedings before submitting more detailed observations.

Though this article seems to imply the opposite:

Thus, the main objective of improving the quality of patents or of preventing frivolous and unworthy patents from being granted gets defeated if the national patent offices choose to ignore the comments. In such cases, the third party who filed the observation [at the PCT] has to ultimately wait for the national phase prosecution in order to take appropriate further action to challenge the invention and present its arguments.

  • "Patent offices offering third-party observations/submissions generally impose a limit on the number of TPOs than can be filed anonymously." They do? I didn't know that, do you have a source?
    – user18033
    May 4, 2018 at 6:01
  • E.g. at the EPO: "the EPO ... allow[s] unsigned third-party observations to be filed anonymously, but only at first instance." epo.org/law-practice/legal-texts/html/caselaw/2016/e/…
    – user132162
    May 4, 2018 at 14:34
  • 2
    first instance relates to the stage of the proceedings, not the number. For example during an appeal against the decision of an opposition after arguments have been made an anonymous tpo might not be considered.
    – user18033
    May 4, 2018 at 16:12
  • @DonQuiKong Okay, good to know. Thanks for clarifying.
    – user132162
    May 5, 2018 at 0:41

1 Answer 1


Both articles discuss WIPO, EPO and UKIPO practice. There is no limit regarding the number of TPO that may be filed during EPO proceedings. The TPO may refer to novelty (A54 EPC), inventive step (A56 EPC), insufficiency of disclosure (A83 EPC), added subject matter [A123(2)] or even clarity (A84 EPC) and unity (A82 EPC), the two latter notably NOT being a possible ground for opposing the patent.

On the contrary, there is a limit in the number of TPO filed during the international phase, that is up until entry in the EP phase. And in addition one may only attack novelty or inventive step.

On top of that, I personally don't think anyone will bother unless you file those TPO quickly enough before an IPEA is conducted - but IPEA is not always conducted. So what will probably happen is that the TPO filed during PCT phase will be forwarded to the national (or regional) patent offices and the examiner hopefully will take a look at them. If not, you might have to file again.

  • See comment on original question -- there are limits on anonymous TPO filings at least at the EPO. And in the US, only the first TPS is free.
    – user132162
    May 4, 2018 at 14:40
  • So are you saying the PCT TPO is not counted at the national office level (even though it still may be considered by the examiner)?
    – user132162
    May 4, 2018 at 14:41
  • No, they are not counted because they don't have to be counted. You can read what the EPO says about TPO for yourself here: epo.org/law-practice/legal-texts/html/guidelines/e/e_vi_3.htm May 7, 2018 at 8:57

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