The filing of a patent application gives rise to two different rights, namely the right derived from the application in question (ownership), and the right of priority, i.e. the right to claim the priority of a first application in a second patent application that must be filed within a certain period of time, which in the case of patents is of 12 months.
For priority to be valid, essentially two conditions must be met: the second patent application must relate to the same invention and the applicant must either be the same or have acquired the right of priority. Although the second condition (same applicant or applicant entitled to priority) seems an easy formality to fulfil, it actually has its difficulties and requires special attention from applicants.
It is common for the ownership of the first application to be transferred before the second application has been filed. By way of example, it is relatively common, particularly in applications filed in the USA, for the applicants (owners) of the first application to include the inventors and for them to assign ownership to a third party, such as a company, organisation or university. However, the transfer of ownership does not automatically imply a transfer of the right of priority. In particular, the European Patent Office (EPO) applies very strict rules to determine whether, at the time of filing the second application, the applicant is the same or has acquired the right of priority.
For the priority to be valid, the applicant on the filing date of the patent application must be the same as that of the priority application. If it is not, the subsequent applicant must have acquired, on the same date, the right of priority through an assignment agreement with the original applicant.
The assignment of priority must be made in the proper form, which means that it must be made by each and every original applicant and as clearly as possible, ideally by means of a written contract. And not all the evidence that is submitted to prove the assignment of the right of priority will serve the purpose.
In the EPO practice, if not all applicants for the first application are applicants for the second application, and if the former ones do not expressly assign the right of priority to the latter when and as they should, the priority is not valid and this can lead to the loss of the European patent because the defect in the right of priority cannot be remedied. Moreover, the right of priority cannot be assigned a posteriori or retroactively.
This was the case of European patent application No. EP13818570, European national phase of an international PCT application, concerning CRISPR-Cas9 technology in the name of several applicants (The Broad Institute, MIT, Harvard College), which was refused by the EPO due to lack of novelty, motivated in turn by the loss of the right of priority because it had not been assigned at the right time.
This European patent application claimed the priority of a number of provisional applications filed in the United States in the name of several applicants, including the inventors.
In this regard, we recall that the filing date of a European patent application as a national phase of a PCT international application is the filing date of the PCT. Thus, if the PCT international application validly claims a priority, then the effective date of the European patent application, for the purposes of determining its novelty and inventive step, is the priority date. But if the priority is not valid, the effective date is the filing date of the PCT international application.
In the case of the CRISPR-Cas9 patent application, not all the applicants of the provisional applications filed in the United States, which included the inventors, were among the applicants of the PCT international application (The Broad Institute, MIT, Harvard College). In this case, the absent applicants should have assigned to the latter, at the time the PCT international application was filed, not only their right of ownership but also their right of priority, which they did not do.
Since there was no assignment of the right of priority by the absent applicants in the second application, the EPO considered that the priority claim was invalid. Therefore, the EPO considered as the effective date of the European patent application to be the filing date of the PCT application and not the priority date.
The tragedy of the situation is that between the (invalid) priority date and the filing date of the PCT application, the inventors had disclosed the invention, so the EPO revoked the European patent for lack of novelty.
The case had a particular resonance because it concerned a patent on a technology with great economic relevance, related to a molecular tool that allows editing or correcting the genome of a cell and which led to the award of a Nobel prize (granted, by the way, to a different research team from those who lost this European patent due to a defect in priority).
The relevant decision (decision T 0844/18), dated 16 January 2020, can be found in the following link:
Another similar case is that of European patent application No. EP09719907, also a national phase of an international PCT application, on behalf of the Canadian university “The University of Western Ontario”, whose main claim was refused by the EPO for lack of inventive step, due to the fact that priority was lost because it was not assigned in the correct form.
That application claimed the priority of two US provisional applications, filed in the name of three inventors.
During its processing, the EPO requested proof of the assignment of the inventors’ right of priority to the university, and the university submitted only the application documents filed in the US, which included a box relating to “Assignee information”, where the university in question was listed.
The EPO pointed out that this brief information did not demonstrate an assignment of the inventors’ right of priority in favour of the university at the time the PCT was filed. In any event, according to the EPO’s criteria, this document indicated an assignment of ownership, but not an assignment of the right of priority, which are different things. Indeed, an original applicant automatically owns both rights (ownership and priority), but an assignment of ownership does not automatically imply an assignment of the right of priority.
In rejecting the priority claim, the EPO therefore considered that the effective date of the European patent application was the filing date of the PCT international application and not the priority date.
With the misfortune that between the (invalid) priority date and the filing date of the PCT international application, a document was published which, due to the loss of priority, became part of the prior art. This caused the EPO to reject the main claim of the European patent application for lack of inventive step in respect of this document.
Here is the relevant decision (decision T 0407/15) of 27 October 2020:
These cases prove that the correct assignment of the right of priority of a patent is of crucial importance for the prosecution of a European patent application.
Failure to assign the right of priority at the proper time and in the proper manner is an error that cannot be remedied which, together with the disclosure of certain information between what should have been the priority date and the actual filing date, results in the loss of the patent.
Utmost care is a priority when we talk about the right of priority.
By María Ceballos (IP Attorney and Lawyer), Isabela Robledo McClymont (Lawyer) and Robert Roser (IP Attorney and European Patent Attorney) at CURELL SUÑOL SLP