EPO revokes CRISPR patent – a clear cut case of invalid priority?

On 17 January 2018, The EPO revoked one of the Broad Institute’s patents relating to a fundamental aspect of CRISPR technology. The opposition board upheld the EPO's preliminary opinion that the claims were invalid in view of an invalid priority claim. The EPO’s decision is not surprising, given the long-standing approach of the EPO to the primary issue in question, namely that the right to claim priority from an earlier application is afforded to the applicant of the earlier application, or his successor in title, and to no other party.

A decision to uphold the patent would have represented a fundamental change in how the EPO understands priority rights, and it is a sign of the importance of this technology that The Broad considers this a battle worth fighting.

Background

CRISPR-cas9 gene editing technology (CRISPR) provides a cheap, efficient and easy way to precisely modify genetic information. CRISPR has long been the subject of highly contentious patent battles in the US between the Broad Institute and the University of California (UC­), Berkeley. These battles continue to rage, and are likely to represent one of the last contentious cases of the pre-AIA first-to-invent system. A number of CRISPR patents have now been granted in Europe, opening up a new front in the CRISPR patent wars.

The patent

The patent in question EP 2771468 derives from a PCT application on 12 December 2013, claiming priority from 12 US provisional applications, the earliest of which was filed on 12 December 2012. The patent was granted on 11 February 2015 to three co-proprietors, The Broad Institute, MIT and Harvard College, with the following claim 1:

1. A non-naturally occurring or engineered composition comprising:

a Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR)-CRISPR associated (Cas) (CRISPRCas) system chimeric RNA (chiRNA) polynucleotide sequence, wherein the polynucleotide sequence comprises
(a) a guide sequence of between 10 - 30 nucleotides in length, capable of hybridizing to a target sequence in a eukaryotic cell,
(b) a tracr mate sequence, an
(c) a tracrRNA sequence

wherein (a), (b) and (c) are arranged in a 5’ to 3’ orientation,
wherein when transcribed, the tracr mate sequence hybridizes to the tracrRNA sequence and the guide sequence directs sequence-specific binding of a CRISPR complex to the target sequence,
wherein the CRISPR complex comprises a Type II Cas9 protein complexed with (1) the guide sequence that is hybridized to the target sequence, and (2) the tracr mate sequence that is hybridized to the tracrRNA sequence, wherein the tracrRNA sequence is 50 or more nucleotides in length.

Opposition proceedings

During the post grant opposition period, nine notices of opposition were submitted, by parties including CRISPR Therapeutics AG and Novozymes. The opponents requested revocation of the patent in its entirety on a number of grounds, including that the patent was not entitled to claim priority from at least two of the priority documents, including the earliest of the provisional applications US 2012/61736527.

A note on priority: requirements in Europe vs US

Article 87 EPC provides the conditions under which an applicant for an EP patent can claim priority from an earlier application, and mirrors Article 4(1) of the Paris Convention. According to Art. 87(1) EPC, any person who has filed a patent in a state a party to the Paris Convention, or his successor in title, shall enjoy such a priority right to the same invention for a subsequent application. Claiming priority to the earlier application provides the subsequent application with the same effective filing date as the earlier application. This means that disclosures between the filing dates of the earlier and subsequent application cannot be cited against the novelty or inventiveness of the subsequent application.

 It is a long-established principle of EP case law that, for a valid priority claim under Art. 87 EPC, the applicant of the subsequent application claiming priority, who is not the person who filed the earlier application, must be that persons successor in title when the subsequent application is filed. In practice, this means that an assignment from the applicant of an earlier application to his successor after the filing date of the subsequent application, is not sufficient for a valid priority claim under the EPC (T 577/11.3).

So what if an earlier application has more than one applicant? According to current EP case law, in the situation where an earlier application has joint applicants, the right to claim priority from the application is considered to belong simultaneously and jointly to the two applicants (who thus constitute a single legal entity). In practice, this means that the earlier application can only serve as a basis for claiming priority for the filing of a subsequent application that designates all applicants of the earlier application (T 788/05).

It is also possible to assign the right to claim priority from an application separately to the assignment of the application itself. Such an assignment must also take place before the filing of the subsequent application and the requirements for demonstrating such an assignment are stringent, as recently confirmed by the EPO technical Board of Appeal (T 1201/14, IPKat post).

The US has less stringent priority requirements. In the US, in order to result in a valid priority claim, an earlier and subsequent applicant claiming priority must have at least one joint inventor in common (MPEP § 213.02). Consequently, when a US provisional application is filed in the name of the inventors, with assignment from the inventor to the owner after the filing date, there is no requirement in the US for the assignment to occur before the filing of a subsequent PCT application claiming priority from the provisional.

Overturning EPO case law on priority -
a mountain to climb?

An invalid priority claim for the CRISPR patent?

The Broad Institute and its co-proprietors have fallen foul of the trap opened up by the difference in the US and Europen requirements for a valid priority claim. In their grounds of opposition, the opponents all argued that the EP 2771468 priority claims to the US provisionals US and 2012/61736527 and US 2013/61748427 (P1 and P2 in the opposition proceedings) were invalid, on the grounds that one or more of the applicants of P1 and P2, or their successors in title, were not listed as applicants for the PCT application from which EP 2771468 was derived.

As matter of objective fact, it appears that the opponents observation is correct. The priority documents listed Luciano Marraffini of Rockefeller University as an applicant. Marraffini does not appear as an applicant on the PCT application forming the basis of EP 2771468, and no evidence was submitted to proceedings that Marraffini had assigned his rights to The Broad Institute before the filing date of the PCT application.

In response, the proprietors argued that the EPO case law is not in line with the principles of the right to claim priority under Article 87 EPC and the Paris Convention.

Luciano Marraffini

A key aspect of the proprietors' arguments in response to the objection was that the right to claim priority under Article 87 EPC should be interpreted according to national law. In their written reply to the notice of opposition, The Broad argued that each of P1 and P2 disclosed more than 1 invention (as is common in US provisional applications). Under US law, they observed that it is a requirement for all the inventors that contributed to the subject matter of the invention(s) disclosed anywhere in a provisional application (whether the description, drawings or claims) are named as applicants. They further observed that to be named as an inventor on a patent application, one has to be the inventor or have derived the right from the inventor, and that under US law an inventor can only assign rights to inventions, and the right to claim priority from such inventions, to which she/he has contributed.

Therefore, it was argued, only the inventor-applicants with the right to claim priority from the subject matter of P1 and P2 to which the subsequent PCT application was directed, were listed on the PCT application. Marraffini, the Broad argued, did not have the right to the invention to which the PCT application was directed and therefore was not listed as an applicant for the PCT application.

To complicate matters further, whilst opposition proceedings were progressing before the EPO, The Broad Institute and the Rockefeller University were locked in a patent dispute over whether Luciano Marraffini should be included as an inventor on the patent. This issue was settled following arbitration on January 15th 2018 (i.e. two days before proceedings) and it was agreed that Luciano Marraffini of the Rockefeller would not be named on the patent. A press release to this fact was submitted during oral proceedings itself (although this was rejected by the Opposition Division for having been filed late).

To support their position, the Broad submitted declarations from such eminent figures as Lord Hoffman.

The Decision

In oral proceedings, the EPO upheld its preliminary opinion that the priority claim was invalid, and that disclosures between the filing date of the US provisionals and the filing date of the PCT application were citeable against the claims. In their preliminary opinion, the EPO emphasized that “in both the EPC and the Paris Convention systems the decisive fact for a valid claim of priority is the status of the applicant, rather than the substantial entitlement to the subject matter of the first application” (EPO's own emphasis).

Those of us not lucky enough to attend the public proceedings await publication of the decision. However, it seems the priority issue was dealt with even more swiftly than expected, given that the scheduled four days of argument were completed in a day and a half.

Appeal

It is testament to the value of the CRISPR technology, that The Broad has already filed a notice of appeal against the decision. A hint as to the grounds under which they will appeal may be found in the Broad’s press release. They appear to accept that the EPO’s decision was in line with the EPO’s own “formal requirements”, but argue that these requirements are inconsistent with the principles of priority provided by the Paris Convention and Article 84 EPC. The Broad Institute proclaims themselves confident that “the EPO will, on appeal, harmonize the EPO procedures to be consistent with international treaties and compatible with the fundamental principles of the Paris Convention”.

This Kat admires The Broad’s optimism!

Author: Rose Hughes