Filing third party observation of a PCT application – a double edged sword

On 2 July 2012, the World Intellectual Property Organisation (WIPO) introduced the opportunity for third parties to submit to International Bureau (IB) observations in the form of prior art relating to a published Patent Co-Operation Treaty (PCT) application. This prior art includes documents that the third party believe are relevant to the novelty and/or inventive step of an invention which is the subject of a PCT application.


As with all steps in the process of obtaining patent protection there are a number of tactical considerations to keep in mind.

The Essentials

  • Third party observations can be made at any time from the date of publication of the PCT application until the date of 28 months from the earliest priority date of the PCT application.
  • The submission of documents can only be in relation to the novelty and inventive step of the claims of the PCT application (although this may change in future to incorporate other areas of patentability).
  • No official fee is payable for the use of this service.
  • Although there is a need to create a user profile with WIPO to submit third party observations, the third party can choose to publish their observations anonymously.
  • A person may only make a single observation on any particular PCT application.
  • A maximum of ten observations (from ten different people) may be submitted on any particular PCT application.
  • An observation consists of a list of at least one and up to a maximum of ten citations, with a brief explanation of the documents’ relevance to novelty and/or inventive step.
  • The applicant of the PCT application will be notified of any third party observations and has the option of responding to observations up until 30 months from the priority date.
  • Observations will be published (excluding copies of cited documents).

The Process

A third party observation must be submitted through WIPO’s online ePCT system. As such, there will be a need to have a WIPO user account and log in directly to ePCT public services, or via a link on the bibliographical data tab of the published international application in PATENTSCOPE (“Submit Observation”). A WIPO user account can be created at the following website:

When entering a citation the ePCT system will prompt the third party to enter in bibliographic details of the citation and an indication of the relevance of the citation. This should include: an indication of the most relevant passages or drawings in the citation and a brief indication of how the document is relevant to the novelty or inventive step of specific claims of invention of the PCT application.

The third party may also upload a copy of the citation in PDF format (although this is not necessarily required and the copy of the citation will not be published).

The Double Edged Sword (Pros and Cons)

There are a number of reasons for and against submitting third party observations. You may wish to consider the following pros and cons.


  • Third party observations will bring prior art to the attention of all the patent offices before which national phase applications for the PCT application are examined.
  • Third party observations with good prior art may make it difficult for the applicant of the PCT application to get granted protection.
  • Third party observations can be filed anonymously.
  • There is no official fee involved in filing third party observations.


  • Good prior art may result in a stronger granted patent that is harder to invalidate.
  • Your negotiating position may be weakened if the observations are deemed not relevant.
  • Each person only has one opportunity to submit observations so if you submit prior art and find more art later, you will be unable to submit this.
  • The patent offices in the major jurisdictions will perform their own prior art searches anyway based upon local laws.

Other Considerations

If you are considering submitting third party observations, it is probably only worthwhile submitting documents that relate to the novelty of the PCT application. The requirement of novelty is more closely aligned across jurisdictions and, as such, anything submitted will likely carry more weight when the respective patent offices examine the national phase applications. With regards to inventive step, the laws in different jurisdictions can differ significantly. As such, any submissions made may not apply in all jurisdictions with regards to inventive step.

On the other side of the coin, if a third party submits observations to your PCT application, one valid strategy would be to not respond at all. If the applicant responds to a submission, this may present an idea of what the applicant considers commercially important and the direction their technological development is heading. Accordingly, from the applicant’s point of view, it may be worth keeping your cards close to your chest and waiting for the national patent offices to examine the application before responding.

However, if you do wish to respond a third party observations that has been submitted against your PCT application, we would recommend doing so after the deadline of which third party observations can be submitted. The rationale behind this timing is so that these will be no further opportunity for others to file further third party observations so essentially, you get the last say in the matter during the pendency of the PCT application.