Claiming Priority at the EPO
10 March 2021
It is important to ensure that a patent application correctly claims priority. There have been a number of cases before the EPO where this has not been done and the priority date has been lost, resulting in the application being refused, or the granted patent being revoked, due to prior art published during the priority period becoming citable.
What is the issue?
The right to claim priority from a priority application (e.g., a US provisional application) belongs to the applicant(s) of the priority application or their successor in title (Article 4 of the Paris Convention and Article 87(1) EPC).
The applicant(s) of the subsequently filed priority-claiming application (e.g., a PCT application) must have the right to make the priority claim at the time of filing. The applicant(s) of the priority-claiming application have this right under the following circumstances:
- The applicant(s) of the priority-claiming application is/are the same as the applicant(s) on the priority application; or
- The applicant(s) of the priority application assigned the right to claim priority to the applicant(s) of the priority-claiming application before the priority-claiming application was filed.
Issues with Joint Applicants
When a priority application lists multiple parties as applicants (e.g., A and B), in the absence of any assignment of the right to claim priority to another party, both A and B must be listed as applicants on the priority-claiming application (see T382/07).
Furthermore, if A assigns the right to claim priority to C, and B assigns the right to claim priority to D, then both C and D must be indicated as the applicants on the priority-claiming application.
Issues with Employment Contracts
In the US, a priority application (e.g., a US provisional application) often lists the inventors as the applicants, whereas the priority-claiming PCT application lists the inventors’ employer as the applicant. In such a situation, it is necessary to demonstrate that the right to claim priority was, prior to filing the PCT application, assigned to the employer. The best way to demonstrate this is via a signed and dated assignment document; however, if such a document does not exist, the employment contract may be able to rescue the situation. In particular, if the employment contract states that the employee “hereby assigns all rights” relating to any invention made under the terms of their employment, it should be possible to successfully argue that the right to claim priority was assigned. Importantly, if the employment contract states that the employee “hereby agrees to assign all rights” relating to any invention, this is generally not considered to be sufficient to demonstrate that the rights have actually been assigned.
Of course, if the applicant(s) of the priority patent application (e.g., the inventor(s)) have signed an employment contract in which they “hereby assign all rights” to their employer, then the right to claim priority has passed to the employer, and the employer needs to be indicated as the applicant on the priority claiming application. Accordingly, there may be situations where the inventors are indicated as the applicants on the priority application and on the priority-claiming application, but, because of the employment contract, the right to claim priority did not belong to the inventors at the time the priority-claiming application was filed. This can result in the priority claim being lost.
Issues with PCT Applicants in Respect of the US Only
In some situations, a priority patent application (e.g., a US provisional application) will list the inventors as the applicants, whereas the priority-claiming PCT application lists the inventors as applicants in respect of the US only, and the employer as the applicant in respect of all other states. In the absence of the priority claim being assigned from the inventors to the applicant prior to the PCT filing date, will the indication of the inventors being applicants in respect of the US only be sufficient to establish that priority has been correctly claimed? This matter is currently being considered by the EPO Board of Appeal in two cases (T2749/18 and T1837/19), but a decision is not expected for a while.
Is Entitlement Relevant?
The question of who is entitled to the invention is irrelevant when determining who has the right to claim priority (see T 5/05). The right to claim priority belongs to the party or parties indicated as the applicant(s) on the priority application, irrespective of whether they are entitled to the invention or not.
What to do
When filing a priority-claiming application it is necessary to determine who has the right to claim priority. In the absence of any assignment (either an actual assignment or via the employment contract) the right will belong to the party or parties indicated as the applicant(s) on the priority application. The party or parties indicated as the applicant(s) on the priority application should therefore be indicated as the applicant(s) on the priority-claiming application.
When there is a clear assignment of the right to claim priority from the party or parties indicated as the applicant(s) on the priority application to another entity, that entity should be indicated as the applicant on the priority-claiming application.
When it is not clear whether the right to claim priority from the party or parties indicated as the applicant(s) on the priority application has passed to another entity, it is generally recommended to file the priority-claiming application listing the party or parties indicated as the applicant(s) on the priority application and the entity to which the right may have been transferred. Any necessary changes to the applicants to correctly reflect the ownership can be made subsequently, but on filing the priority-claiming application it is essential that all parties that have, or may have, the right to claim priority are listed as applicants.
Adrian Tombling
Life Sciences & Chemistry group
This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.
© Withers & Rogers LLP March 2021
