A Short Guide: Priority Entitlement at the EPO

Article 87 EPC

Priority right

(1) Any person who has duly filed, in or for (a) any State party to the Paris Convention for the Protection of Industrial Property or (b) any Member of the World Trade Organization, an application for a patent, a utility model or a utility certificate, or his successor in title, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application.

Article 87 EPC is based on Article 4A of the Paris Convention:

(1) Any person who has duly filed an application for a patent, or for the registration of a utility model, or of an industrial design, or of a trademark, in one of the countries of the Union, or his successor in title, shall enjoy, for the purpose of filing in the other countries, a right of priority during the periods hereinafter fixed.

Invalidity of a priority claim of a patent on the grounds that, at the filing date of the patent, the applicant did not have the right to claim priority, has become a concern for patentees as well as an opportunity for opponents at the EPO in recent years. This short guide aims to summarise the EPO’s current practice as well as provide some best-practice points for guarding against loss of priority in this way.

Importantly, only in the case that the validity of a priority claim is objected to (due to the presence of an intermediate document relevant for the assessment of novelty or inventive step) will the EPO assess whether the earlier application (or the priority right as such) has been transferred before the filing date of the later [European/ PCT] application.

The priority right

The filing of a first application in or for a state party to the Paris Convention creates two distinguishable rights for an applicant. The first is the right to the grant of a patent from that application, having effect in that state. The second is the right to claim priority from that application in a later application in or for a state that recognises the earlier application as giving rise to a right of priority.

EPO Boards of Appeal have found that priority rights are assignable independently of the corresponding patent application, and furthermore their assignment may be restricted to specific countries (T62/05, T205/14).

As such, irrespective of whether the earlier application itself is being assigned, an assignment should refer to the earlier application by its official number and explicitly state that the right to claim priority from that application is assigned, as well as the right to be granted a patent for that invention in the states covered by the later application e.g. PCT contracting states.

Assignment before filing the later application

EPO Guidelines for Examination A III 6.1 state that the transfer of the application (or of the priority right as such) must have taken place before the filing date of the later application. An assignment from the applicant of an earlier application to his successor after the filing date of the later application, is not sufficient for a valid priority claim under the EPC (T577/11). Proof of this transfer can however be filed later.

Effective transfer under national law

The transfer of the application (or of the priority right as such) must be a transfer valid under the relevant national provisions (T1008/96). According to the EPO Guidelines and case law, the assessment implicitly requires establishing which law is applicable to determine the validity of a transfer, what the requirements of said law are, and whether these requirements have been fulfilled in the particular case in question. The choice of the applicable national law depends on the circumstances of the particular case. For example, in T205/14, the Board considered both the law of the country where the earlier applications were filed and the law governing the relations between the parties to the transfer of the right of priority and concluded that, in that case, the former was the law determining the transfer.

Standard and burden of proof

It is not settled whether the EPO will require the same standard of proof as that required for assignments (i.e. in writing and signed by both parties to the transaction) since there are conflicting decisions (e.g. T62/05 and J19/87) on this point. Where possible, it is therefore advisable to adopt a cautious approach. As to the question of the burden of proof, if entitlement to priority is challenged, the successor in title has to prove his entitlement to that right (T205/14).

The named applicant

Omitting applicants

It is existing EPO practice that an earlier application can only serve as a basis for claiming priority for the filing of a later application if the later application designates all applicants of the earlier application or their successor(s) in title (the so-called “same applicant” test- T788/05 and UK decision Edwards Lifesciences AG v Cook Biotech Inc [2009] EWHC 1443 (Pat)).

This practice was very recently confirmed in EPO Appeal decision number T844/18, relating to The Broad Institute’s CRISPR European patent (EP2771468), based on a PCT filing (WO 2014204729) claiming priority from a number of earlier US provisional applications. This issue arose because one of the US provisional applications named an inventor-applicant and neither he nor his successor in title was named as an applicant for the PCT application. In the Opposition proceedings involving 9 opponents (reduced to 7 at Appeal), it was alleged that by application of the “same-applicant” test, the priority claim was invalid. If correct, this had the consequence that certain intervening documents became citeable, which were not disputed to be novelty destroying. At first instance, The EP patent was revoked by the EPO Opposition Division.

The Broad Institute appealed the decision on the basis of three main legal arguments:

• the EPO does not have jurisdiction to examine who has the right to claim priority
• the construction of “any person” within Article 4A(1) of the Paris Convention and Art. 87(1) EPC means, in the context of a group of co-applicants, “any one of” those co-applicants
• the national law of the territory of the earlier filing should govern who is "any person" who has duly filed the application within Art. 4A(1) of the Paris Convention and Art. 87(1) of the EPC

The Oral proceedings were held in January 2020, focussing on this specific legal point. Despite some early signs that the Board of Appeal might refer the matter to the Enlarged Board of Appeal, ultimately they followed current EPO practice and upheld the decision of the Opposition Division.

Adding applicants

In the case of joint applicants filing the later European patent application, existing EPO practice is that it is sufficient if one of the applicants on the later application is the applicant or successor in title to the applicant of the previous application (the so-called “co-applicant approach” or “joint applicant approach”- see UK decision KCI Licensing Inc v Smith & Nephew plc [2010] EWHC 1487 (Pat)). The “joint-applicant approach” to priority also derives from T 1933/12 (German language; 21 February 2014; Board of Appeal 3.2.08). The Board reasoned that Article 87(1) EPC does not prevent an applicant for an earlier application sharing their right to priority with a co-applicant for a later application claiming priority from that earlier application.

Two recent Opposition Division decisions from October 2018 and April 2019 have applied the existing “joint-applicants approach” to a new context, namely the situation where the inventors are named as the applicants on a US application and a PCT application is filed claiming priority from the US application naming the US inventors as inventor-applicant for the US only and a different applicant for the remaining designated states. The decisions relate to GSK’s European patent EP1965823 and AbbVie’s European patent EP2940044. In applying this approach, these Opposition Divisions appear to consider that EPO practice allows the priority right owning applicant on the earlier US application (i.e. the inventors) to introduce the priority right into the PCT application by being the US-only applicant, whereby the right has full effect for the PCT application as a whole.

This is not the approach that has been taken by the Board in e.g. T 205/14 and T 517/14 in which, in an analogous situation, the Board required evidence of a transfer of the right to priority to the ‘additional’ PCT applicant from the inventor-applicants of the priority applications. Clarification is required from the pending appeals relating to the GSK and AbbVie cases.

In the GSK case, the Opposition Division did note however that the “joint-applicants approach” may not be applicable in very specific cases if, for example, (i) there is an indication that the inventors i.e. the applicants for the US only, may not even have been aware of the filing of the international application, or (ii) if the right of priority devolved from the inventors to the employer by operation of law once the invention was conceived and the priority application filed (since the inventors would no longer own the priority right and could not therefore introduce it into the PCT application).

It will therefore be interesting to follow the GSK and AbbVie Appeals.

Best-practice points

An assignment should:

• refer to the earlier application by its official number
• explicitly state that the right to claim priority from that application is assigned, as well as the right to be granted a patent for that invention in the states covered by the later application e.g. PCT contracting states
• be dated before the filing date of the later European application
• fulfill the requirements of the law in the country where the earlier application was filed and the law governing the relations between the parties to the transfer
• be in writing and signed by both parties to the transaction

The later application should:

• name all applicants of the earlier application or their successor(s) in title
• name the above as applicants for the EP designation if the later application is a PCT application.