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The applicability of new Rule 20.5bis PCT at the European Patent Office

The European Patent Office (EPO) issued in June 2020 a notice (Official Journal June 2020, A81) outlining its practice with regards to newly introduced Rule 20.5bis PCT.

Rule 20.5bis PCT lays out the conditions for requesting the correction of an erroneously filed element or part of a PCT application. This provision complements Rule 20.5 PCT which covers remedying an application having a missing part or parts where nothing was erroneously filed. The EPO uses the words “truly missing” for the case of Rule 20.5 PCT, and adopts the PCT language of “correcting [an erroneously filed element or part]” for the case covered by R20.5bis PCT. The PCT allows in principle incorporation by reference in either case. Under incorporation by reference the applicant may furnish late an element/part without getting a later international filing date, provided the element/part is completely contained in the priority document and a two-month time limit (Rule 20.7 PCT) for filing the confirmation of incorporation is met. 

The EPO has announced that Rule 20.5bis PCT is partially incompatible with the EPC’s current legal framework. The notice serves to outline the EPO’s practice with regard to this provision.

EPO as Receiving Office

The EPO as receiving Office will not process the correction under Rule 20.5bis PCT if the correct element or part is furnished by means of incorporation by reference. It will continue to process the request for late furnishing of the correct element or part if incorporation by reference is not used.

But in the former-mentioned case of using incorporation by reference, the request may still be processed if the applicant agrees to transmit the application to the International Bureau (IB) who will subsequently act as receiving Office (Rule 19.4(a)(iii) PCT). Unlike the EPO, the IB does accept the correction of erroneously filed elements or parts by incorporation by reference.


The EPO as International Searching Authority (ISA) will accept a decision made by the receiving Office to grant incorporation by reference and will perform the search on the application including the correct element or part, as long as the receiving Office notifies the EPO of the correct element or part before the start of the search. Even if the EPO is notified after the start of the search (including after its completion), the correct element or part can still be included in the search if an additional fee equal to the search fee is duly paid.

The EPO will perform any international preliminary examination on the basis of the application as searched by the ISA.

Procedure before the EPO as designated or elected Office

The EPO will not accept a decision by the receiving Office that the correct documents under Rule 20.5bis PCT have been incorporated by reference , i.e. without changing the filing date. In this case, in what the EPO calls the “standard procedure”, the EPO will notify the applicant that it will:

  • consider the filing date of the application to be the date on which the correct documents were received, and
  • disregard the erroneously filed documents,

unless the applicant responds by requesting to pursue instead the erroneously filed documents. The notification is referred to as the “communication under Rules 20.8(c) and 82ter.1(c) and (d) PCT” and there is a two-month time limit to respond.

As an alternative to the “standard procedure” described above, the applicant may use the so-called “abridged procedure”, namely to inform the EPO of its choice at an earlier stage, i.e. within the 31-month time limit under Rule 159(1) EPC or at the latest before the above-mentioned communication under Rules 20.8(c) and 82ter.1(c) and (d) PCT is issued. In this case the EPO does not send said communication.

Furthermore under the “abridged procedure” the applicant gets the opportunity to exclude the unwanted application documents from the calculation of the additional fee for pages in excess of 35 (Art. 2(1).1a, Rules Relating to Fees) – provided that the applicant informs the EPO within the 31-month time limit under Rule 159(1) EPC and before any additional fee is paid.

Possible outcomes at the EPO as designated or elected Office

In conclusion the applicant may pursue either:

  1. the correct application documents, with the date of receipt of those application documents being used as the filing date, with the erroneously filed documents being disregarded, or
  1. the erroneously filed application documents with the filing date initially accorded being used as the filing date, with the correct application documents being disregarded.

Changing the filing date to a later date may result in the loss of the priority right. A request for restoration of the right of priority may be made to the EPO (Rule 49ter.2 PCT).

The practical outcome is that any negative decision on incorporation by reference will be made by the EPO in its regional phase and not in the international phase, leading to minimal negative consequences for the applicant in the international phase. In the case of correcting erroneously filed documents by incorporation by reference all documents remain in the application during the international phase and are published by WIPO. The act of replacement is effectively completed in the national or regional phase when the erroneously filed documents are disregarded.


Newly introduced Rule 20.5bis PCT comes after several years of discussion among WIPO and Offices on how Rule 20.5 PCT is to be interpreted. Some Offices (e.g. USPTO and IB) considered Rule 20.5 PCT to allow the inclusion of, for example, a new complete set of claims after an erroneous set was filed, while others (e.g. EPO) saw Rule 20.5 PCT as not permitting this. While there are still divergent views among the Offices regarding correcting erroneously filed elements or parts, newly introduced Rule 20.5bis PCT allows the Offices to consider Rule 20.5 PCT with a consistent interpretation (i.e. that it applies to the case of “truly missing” parts only), and to register any incompatibilities under the newly introduced Rule 20.5bis PCT that provides for correcting erroneously filed elements or parts.

Note that the German Patent and Trademark Office as receiving Office and as designated or elected Office continues to refuse incorporation by reference requests in both cases. (Rule 20.5 PCT and Rule 20.5bis PCT).

Official Journal June 2020, A81:


WINTER BRANDL Partnerschaft mbB, Munich, European Patent Attorneys Timothy Chettle and Michael Schüller