Invalid claim to priority brings down Broad Institute’s original CRISPR patent at the EPO


Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a natural defence system used in bacteria which has been modified for use in genomic engineering and become one of biotech’s most lucrative technologies, predicted to be worth $2.3 billion by 2022.  CRISPR can be used to correct mutations at targeted DNA locations, providing the potential to modify the genome to correct genetic diseases.

Currently, there are two major parties at the forefront of patents regarding the use of CRISPR; The University of California, Berkeley and The Broad Institute.  These parties are involved in a long running dispute over who should have the benefit of the rights to the initial CRISPR technology.

In the US, The University of California first filed a provisional US application for the general use of CRISPR for targeted DNA modification. In the same year, The Broad Institute filed a provisional US application for the use of CRISPR for targeted DNA modification specifically in eukaryotic cells, but requested accelerated prosecution. As a result of accelerated prosecution, The Broad Institute was granted the first CRISPR patent in April 2014.  The University of California requested interference proceedings in the US, arguing that they were the first to invent the CRISPR tool.  However, the US Patent and Trademark Office ruled that each party claimed patentably distinct subject matter in the two patents and therefore, each party could be granted their own patent.  This means that companies working on CRISPR in the US could need a license from both The University of California and The Broad Institute, because the eukaryotic route looks the most commercially promising.

In Europe, the Broad Institute have a number of CRISPR patents in opposition.  The opposition division at the EPO announce their decision to revoke Broad Institute’s original CRISPR patent on 17 January 2018, based on a lack of novelty arising from an invalid priority claim.


The patent (EP2771468) claimed priority from twelve US provisional applications, which named the inventors as applicants.  However, when the PCT application was filed, it did not name all of the inventors/applicants of the provisional application as applicants of the PCT application.

According to Article 87(1) EPC, the right of priority belongs to”Any person who has duly filed…an application for a patent…or his successor in title”. In order for a patent to validly claim priority from a priority document, the applicant of the patent must be the same as the applicant of the priority document (or his successor in title), or, the right to claim to priority must be transferred from the applicant of the priority document to the applicant of the priority claiming applicationbeforethe latter is filed.

In accordance with established case law, if there are a number of applicants on the priority applications, then the right to priority belongs to all the applicants. Consequently, all of the applicants of the priority documents need to be named as applicants (or their successor in title) in the priority claiming application, or, they must transfer their rights to priority to the applicants named on the priority claiming application before the latter is filed.

In this case, the PCT application which led to the European patent was filed in the name of The Broad Institute, Massachusetts Institute of Technology, and The President and Fellows of Harvard College.  However, an inventor/applicant Luciano Marraffini named on a number of the US provisional applications, including the earliest two priority documents, was not named an applicant of the PCT application, nor was his successor in title; The Rockefeller University.

Therefore, the opponents argued that Luciano Marraffini did not transfer his right to claim priority to the applicants named on the PCT application; neither did his successor in title, and therefore the patent lacked a valid priority claim.  The patentee did not submit any evidence to dispute this but argued  that Luciano Marraffini did not make any contribution to the inventions in the earliest two priority applications and so had no priority right to transfer.  They argued that this matter should be considered under US law, and that the requirements of Article 87 EPC were fulfilled since all persons, who under US law are considered to have contributed to the same inventions disclosed in the first two priority documents were later claimed in the PCT application, were named as applicants in the PCT application.

In their preliminary opinion, the Opposition Division stated that the formal validity of the priority claim for the European patent must be assessed within the EPC legal framework.  They confirmed that the right to priority constitutes a legal right, which is independent of the right to entitlement.  In both the EPC and the Paris Convention, the decisive fact for a valid claim of priority is the status of the applicant, rather than the entitlement to the subject-matter of the first application.  They concluded that there was no evidence that the priority rights of Luciano Marrafini had been transferred into the PCT application before the PCT filing date, and therefore the right to claim priority from at least the earliest two priority documents was invalid.

The Opposition Division upheld their preliminary opinion. The European patent was found to lack a valid claim to priority, and therefore, the patent was found to lack novelty in light of a number of intervening documents.

We look forward to the publication of the full decision to determine whether the Opposition Division fully followed the reasoning in their preliminary opinion.

The Broad Institute has already announced via their website that they plan to appeal the decision to the Boards of Appeal at the EPO, stating that they consider the decision is “unrelated to the substantive merits of the CRISPR patent” and based on a formal technical requirement that they consider to be  inconsistent with the Paris Convention and other treaties “designed to harmonise the international patent process”.

Practice points

This case highlights the importance of ensuring that the claim to priority is valid, and that all necessary transfers of the applicant(s) priority rights have taken placebeforefiling a later priority-claiming application before the EPO (either a PCT application or a direct EP application).

On the one hand, if the Board of Appeal upholds the Opposition Division’s decision, this priority issue will likely impact a large number of the Broad Institute’s other CRISPR patents that have the same issue. On the other hand, if the Opposition Division’s decision is overturned, this will contradict established EPO case law on priority rights, which would likely impact many fields of technology, not just the world of biotech.  We are watching the appeal with interest.

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


Charlotte Teall and Kate Selwyn