International (PCT) patent application procedure

This page summarises the application procedure relating to the Patent Cooperation Treaty (PCT). For an introduction to the PCT please read our article What is an International (PCT) patent application?

Filing a PCT application

In order to file an international (PCT) patent application, it is necessary to finalise an appropriate patent specification. The application documents include the specification and drawings and specify details of the applicant and inventors, amongst other things.

Usually, an international patent application will claim priority from one or more earlier applications filed by the same applicant. The international application must be filed by the first anniversary of the filing date of the earliest of these applications, which must be the first application by the same applicant for the same invention.

For our UK-based clients we typically file PCT applications through the UK IPO as receiving office although for international clients it is sometimes necessary to file PCT applications through the European Patent Office or WIPO as receiving office, depending on nationality and residence regulations.

PCT applications are usually filed electronically and a filing receipt and application number is immediately generated. Sometimes formal objections are raised to the drawings in which case it is necessary to have formal drawings prepared and filed.

Search, written opinion and publication

All of the subsequent deadlines are calculated from the filing date of the earliest application from which priority is claimed, referred to below as the “earliest declared priority date”.

Once an international (PCT) patent application has been filed and the necessary formalities (such as the submission of formal drawings) have been complied with, the application is transmitted to the World Intellectual Property Organisation and then searched by the European Patent Office acting in their capacity as an International Search Authority. A Written Opinion is issued with the search, which summarises the views of the International Search Authority as to the patentability of the invention. The search typically issues after three to seven months, although they will very occasionally decline to carry out a search where they consider the subject matter to be inherently unpatentable, for example if it is devoid of technical character.

The application is published shortly after eighteen months from the earliest declared priority date. Accordingly, although the search report will often be issued well before publication, this is not always the case and many applications are published without the search report and republished with the search report at a later stage.

It is possible to withdraw an international (PCT) application to prevent it from being published. A request for withdrawal must reach the international bureau by the date when technical preparations for publication are complete. Guidelines indicate the date by when this request must be received, although any request for withdrawal should be filed well before this date.

Chapter II

If you wish to challenge the views set out in the Written Opinion, you can request for it to be reviewed by filing a so-called “Chapter II Demand” and submitting written arguments and/or claim amendments. The deadline for filing a Chapter II Demand is 22 months from the earliest declared priority date, or three months from the date of transmittal of the Search Report and Written Opinion, whichever is later. If you file a Chapter II Demand, an International Preliminary Report on Patentability will be prepared on the basis of any revised claims which have been submitted, taking into account the arguments submitted with the demand. Otherwise, an International Preliminary Report on Patentability will be issued which simply reflects the Written Opinion. Filing a Chapter II Demand is expensive but is optional.

Entering the national/regional phase

By a deadline of not earlier than 30 months from the earliest declared priority date it is necessary to enter the national or regional phase in respect of territories where protection is to be sought. Although the deadline for national/regional phase entry is 30 months from the earliest declared priority date in respect of many territories, e.g. the US, there are quite a number of territories which allow a further one or two months. For example, the deadline for entering the UK national phase or European regional phase is 31 months from the earliest declared priority date. Some territories allow national or regional phase entry to take place one or two months late on payment of a surcharge.

After entry into the national/regional phase, the application procedure proceeds in the same way as direct national and regional patent applications in respect of each territory.

Costs on national/regional phase entry vary substantially between countries. They are generally highest in countries which require the patent specification to be translated.

Thereafter, the application procedure continues in individual territories where national/regional phase applications were filed. In principal examination is carried out independently in each territory although the International Preliminary Report on Patentability will typically be used as a starting point and examiners do routinely view the examination procedure in other territories online and this is sometimes apparent.

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