EPO’s Technical Board of Appeal upholds decision to revoke key CRISPR/Cas9 patent


The EPO’s Technical Board of Appeal has upheld the decision of the Opposition Division to revoke The Broad Institute, Inc., Massachusetts Institute of Technology, and President and Fellows of Harvard College’s patent relating to CRISPR/Cas9 technology (EP2771468).

While the decision may perhaps be unsurprising given the amount of case law that supports the actions of the Opposition Division, the decision confirms the requirements for a priority claim to be deemed valid in Europe. A summary of the facts of the case and the relevant law is provided below.


In Europe, the right to claim priority from an earlier application is dealt with under Article 4(A) of the Paris Convention and Article 87 of the European Patent Convention.

Briefly, these legal texts state that “any person who has duly filed […] an application for a patent […], or his successor in title, shall enjoy, for the purposes of filing a European patent application for the same invention, a right of priority during a period of twelve months from the date of filing of the first application.”

EPO case law has interpreted the term “any person” to relate to all applicants named on the priority application meaning that a priority claim is only valid if all the applicants of the priority application (or their successor in title) are named on the priority-claiming European application at the time of filing. Examples of valid priority claims and the transactions involved are illustrated below:

If the priority requirements are met, the effective filing date of the European patent application is the same as the earlier-filed priority application. Therefore, any disclosure occurring after the priority date will not be citeable against the European patent application.

The decision of the Opposition Division (see our full report here)

The Opposition Division declared that the priority claim was invalid because one of the applicants named on some of the earliest priority documents was not also named on the PCT application from which the European application was derived. The below figure shows why the priority claim was deemed invalid.

The loss of priority meant that the European patent was not entitled to the earlier date of the priority applications causing a document published after the priority date to become citeable. This document was novelty-destroying causing the Opposition Division to revoke EP2771468.

The appeal

The patent proprietors appealed the decision of the Opposition Division to revoke EP2771468.

The patent proprietors presented three main arguments, namely that:

  1. The EPO was not competent to assess entitlement to claim priority and that this should be dealt with in national courts.
  2. “any person” in Article 87(1) EPC should be interpreted to mean “at least one” instead of “all”.
  3. National law of the territory of the priority application should dictate the interpretation of “any person”.

After a four day hearing, including some speculation of a referral to the EPO’s Enlarged Board of Appeal, the Technical Board of Appeal decided that they were competent to assess entitlement to claim priority, that priority rights cannot be divided or separated into multiple priority rights and so “any person” must be interpreted as all applicants and that reference to national law was not necessary to interpret the phrase “any person who has duly filed”. In short, the Board disagreed with all three of the proprietor’s arguments.

Therefore, the Board of Appeal dismissed the appeal and the decision to revoke EP2771468 has become final.


While we are awaiting issuance of the written decision, the result serves as an important reminder that, for a priority claim to be valid in Europe, applicants named on the priority application, or their successor in title, must also be named when filing the later priority-claiming application.

If you would like any advice on ensuring your portfolio complies with the European rules on priority rights, please contact your usual Forresters attorney.