In a decision delivered today the European Patent Office revoked a patent relating to CRISPR-Cas9 genome editing technology which had been granted to the Broad Institute, MIT and Harvard University.

This marks the latest development in a series of patent battles being waged over this revolutionary (and highly lucrative) technology. An earlier US decision involving the Broad Institute was reported by us here.

The Broad Institute's patent EP2771468 claimed priority from twelve US provisional applications, some of which had been filed under the old US "first-to-invent" rules and which therefore named the inventors as patent applicants.  Subsequently, an international patent application was filed naming the Broad, MIT and Harvard as applicants. The EPO granted a patent based on that international application.

In its decision, the EPO's Opposition Division held that the right to claim priority in respect of four of the provisional applications had not been properly assigned from the inventors to the named applicants. As a result of this finding, the claims were found to lack novelty over a number of documents which became relevant as prior art due to the lack of priority entitlement.

The Broad Institute has already released a statement highlighting its intention to appeal the decision. In the view of the Broad institute, the question of entitlement to priority should be assessed under US law (i.e. the law governing the country of filing of the priority and international applications), not under EPO rules. The Broad Institute argues that the EPO's approach to priority is inconsistent with the Paris Convention and other international treaties aimed at harmonising patent law worldwide.

If, as expected, the Broad Institute files an appeal, this will have suspensive effect and the Opposition Division's decision will not become final unless the EPO's Technical Board of Appeal confirms it. It is therefore clear that this story has a way to go before it reaches its conclusion.

If the EPO Board of Appeal overturns the decision of the Opposition Division and sides with the Broad Institute on the question of priority, this will mark a radical departure from decades of jurisprudence on a fundamental concept in patent law. Such a decision would have significant repercussions for all technical fields, not just biotechnology. The Appeal will therefore be of landmark importance and is sure to be watched closely by patent practitioners around the world.