How to save your priority date at the EPO – the current state of play
A post-CRISPR perspective

For the past ten years or so the question of whether the right to claim priority has been validly transferred has been raised on a fairly regular basis in contentious proceedings in Europe and particularly the EPO. The nature of the right to claim priority is set out in Article 4A(1) of the Paris Convention (which is mirrored in Article 87(1) of the European Patent Convention).

At its heart, the issue seems to be a very simple one: when filing a subsequent patent application (such as a PCT application) which is claiming priority from an earlier patent application (such as a US provisional application), the party which is the applicant for the subsequent application must be the same as or the successor in title to the party which was the applicant for the earlier application.

This article explains the main principles surrounding how priority rights are assessed in Europe and by the EPO in particular, using this year’s CRISPR case as a powerful example. We also briefly look at the EPO’s joint-applicants approach to rescue priority entitlement in certain situations that US applicants have frequently found themselves in. Finally we touch on a remedial approach which in some circumstances can be used to safeguard the right to claim priority.

The EPO’s CRISPR/Broad decision

The most important point to note upfront is that the issue of priority rights in Europe revolves around the applicant who was named on the priority application and the applicant who was named when the subsequent, priority-claiming application (such as a PCT) was filed. In Europe it’s all about the applicant.

The consequences of getting this wrong can be nothing short of catastrophic, as shown by the EPO’s widely-publicised CRISPR/Broad Institute decision earlier this year, in relation to which the Board of Appeal has recently clarified its reasoning.

The patent in question in the CRISPR/Broad case claimed priority to 12 US provisional applications. It turned out that not all of the applicants of these provisional applications (or their successors in title) were listed as applicants for the PCT. One of the missing applicants was Professor Luciano Marraffini of Rockefeller University. There was no evidence that Professor Marraffini had assigned his rights to the Broad Institute (or any of the other PCT applicants for that matter) before the filing date of the PCT application that resulted in the contested patent.

During first-instance opposition proceedings, the Opposition Division held that the priority claim was invalid. In line with well-established EPO case law, it stated that the decisive fact for a valid claim of priority is the formal status of the applicant, rather than the substantial entitlement to the subject matter of the first application. This decision was appealed, and the key question that the Board of Appeal had to grapple with was this:

“A and B are applicants for the priority application. A alone is the applicant of the subsequent application. Is the priority claim valid even without any assignment of priority right from B to A?”

The appellants (The Broad et al.) asserted that the answer to this question was “yes”, and the respondents said the answer was “no” (which is in line with many years of EPO case law).

The Appeal and where the Broad Institute went wrong

The Broad Institute’s argument was that EPO case law is not in line with the principles of the right to claim priority under Article 87 EPC and the Paris Convention, and the right to claim priority under Article 87 EPC should be interpreted according to national law.

During the appeal proceedings the EPO Board of Appeal considered the following:

  • whether entitlement to claim priority rights should be assessed by the EPO;
  • what the proper interpretation of “any person” in Article 87(1) EPC is; and
  • what the applicable law for interpreting “any person who has duly filed” is.

The Broad approached the issues at hand from the viewpoint of a US practitioner. The meaning of applicant under US patent law differs greatly from the European definition. Under US patent law applicant status is closely tied to inventorship. Inventorship status depends on the contribution a person has made to an invention that is claimed. Accordingly, a person named as an applicant of a first application holds a priority right in respect of the invention to which he or she has contributed. So if a US provisional application discloses multiple inventions, a subsequent second application directed to one of these inventions may claim priority only from those applicants/inventors who have contributed to an invention which has also been claimed in the second application. Persons who have not made such a contribution should not be named as applicants. Following this logic, Professor Marraffini, The Broad argued, did not have the right to the invention to which the PCT application was directed and therefore was not listed as an applicant for the PCT application.

Indeed, The Broad Institute and Rockefeller University had been engaged in a patent dispute over whether Professor Marraffini should be included as an inventor on the patent. This issue was settled following arbitration in January 2018 (just a couple of days before the opposition proceedings) and it was agreed that Luciano Marraffini of the Rockefeller would not be named on the patent.

The Board of Appeal did not agree with the approach taken by The Broad. It considered the Paris Convention as directly applicable US law, but could not find sufficient evidence to suggest that The Broad was right in the interpretation of its provision form a US patent law perspective. The European Patent Convention requires the EPO to assess priority entitlement. The Board of Appeal held that the EPO’s interpretation of the Paris Convention (which is backed by over 100 years of national case law) and the corresponding provisions of the European Patent Convention do not entail an inventorship assessment. In its view and in line with established European practice, priority entitlement had to be assessed on a purely formal basis. This means that all applicants of the first application, or their successors in title, have to be named as applicants on the subsequent second application in order for the priority claim of the second application to be valid (referred to as the “all applicants approach” by the EPO). Accordingly, since there was no transfer of rights in the priority year from Professor Marraffini to the PCT applicants, either Professor Marraffini or his successor in title should still have been named as an applicant when the PCT application was filed.

In short, to The Broad’s detriment, the Board of Appeal upheld established practice at the EPO. Applicants must fulfil chain of title requirements for a valid priority claim:

  • If priority is claimed from a first application with multiple applicants, make sure that all applicants have assigned their rights to the PCT applicant(s) before the PCT application is filed; and
  • If an applicant on the first application has not transferred his or her or its rights prior to the PCT conversion deadline, name him or her or it (where the applicant is an organisation) as a co-applicant on the PCT application.

The PCT Joint-applicants approach – a form of welcome relief?

As alluded to above, a central part of assessing priority entitlement at the EPO is whether the applicant of a subsequent second application is the applicant of the first application from which priority is claimed, or a successor in title. To establish whether the applicant of the second application is the successor in title, the EPO considers the validity of the transfer of the priority right under the national law of the assignment. This has meant that the EPO has had to take a view on points of contract law of various foreign countries.

This approach poses two problems for the EPO – firstly, the side issue around priority entitlement increases the cost and time required to resolve opposition proceedings, and secondly, the EPO is required to judge issues of national law, which is something that does not fit easily within its remit. It is particularly complicated with regard to applications emanating from the USA, where both state and federal law can play a role in assessing the validity of transfer of the right to claim priority from a first application.

As a result, over the past few years we have seen the rise of an alternative approach which, in a way, allows the EPO to side-step this analysis in cases that result from PCT applications with US-based inventors who previously filed a US provisional application as the first application from which a subsequent PCT application claims priority. This alternative approach is known as the “PCT joint-applicants” approach. Under this approach the EPO considers a PCT application as a single (unitary) item rather than an administrative convenience representing a bundle of different patent applications. Accordingly, a US inventor who is named as applicant with respect to the US designation only is viewed as having jointly filed the PCT application together with the corporate applicant named for all other designations. As a consequence, no evidence of transfer of the priority right from the US inventor to the corporate PCT applicant within the priority year is required to confirm priority entitlement.

In short, the PCT joint-applicants approach enables the EPO to consider there to be a common applicant for both the earlier and the later application, even though the common applicant is not an applicant for the EP application that derives from the PCT application. It is worthwhile noting that this approach unfortunately could not have saved The Broad’s CRISPR patent, since Professor Marraffini had never been named as an inventor and applicant on the underlying PCT application.

The PCT joint-applicants approach has been endorsed by a number of opposition divisions at the EPO. Whilst these decisions are not binding, we are aware of one or two (binding) Board of Appeal decisions on the PCT joint-applicants approach there are due to issue early next year – so watch this space.

Requesting correction of the applicant to safeguard the right to claim priority

It’s a fact of life that people sometimes make mistakes – after all that’s the reason why pencils have erasers at the end. When filing a subsequent, priority-claiming application such as a PCT application the incorrect applicant can sometimes be named on the PCT Request form.

For example, a mistake can be made on filing the PCT:

  • If the provisional applicant’s priority rights (or entire rights) were assigned before the PCT filing date, but the PCT application was still filed in the name of the assignor (i.e. the applicant listed on the USPTO filing receipt / inventor), and not in the name of the new owner of the rights, the assignee; or
  • If the provisional applicant’s priority rights (or entire rights) were not actually assigned to the proposed assignee before the PCT filing date, but the PCT application was still filed in the name of the proposed assignee (who didn’t yet actually have the rights).

Such mistakes can sometimes be corrected. To safeguard the right to claim priority, any correction needs to have retroactive effect back to the moment the PCT application was filed – a form of “administrative time travel” if you will. The effect of a retroactive correction (such as via Rule 91 PCT at WIPO or via Rule 139 at the EPO) is that the PCT application is deemed to have always been filed in the correct applicant’s name (at least the EP part of the PCT application, if the correction is made at the EPO). This ability to “time travel” means that if the correction is allowed, as far as the patent office is concerned the mistake was never made. Accordingly, if the error under normal circumstances could have resulted in a loss of priority entitlement at the EPO, the correction should therefore have fixed this problem.

A full discussion of how one would actually go about correcting the applicant as a possible remedy for a priority problem will be discussed in a future article.

Practical considerations

  • If an applicant(s) listed on a first application (e.g. on the filing receipt of the US provisional) and the applicant(s) on a proposed subsequent application (e.g. PCT) are not identical, make sure that all rights (or at least the right to claim priority) have been transferred by a written assignment before the subsequent application is filed.
  • If an applicant on the first application has not transferred his/her/its rights prior to the PCT conversion deadline, name that applicant as a co-applicant on the PCT application.
  • Retroactive correction of an applicant can be used in some circumstances to safeguard a priority claim at the EPO.
  • If the priority entitlement of your patent is being challenged:
    • check whether any assignments were executed before the filing date of the priority-claiming application that could have assigned rights to the subsequent applicant;
    • check any contracts of employment, invention agreements, collaboration agreements or intra-group agreements, to see if they impact on the ownership of priority rights; and
    • check whether the PCT Joint-Applicants approach could provide a possible solution.

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