At the end of 2023, the Enlarged Board of Appeal (EBA) at the EPO issued its decision on consolidated cases G1/22 and G2/22 concerning the legal right to claim priority. Recent Board of Appeal decisions following G1/22 and G2/22 confirm that the EPO has relaxed its stance and is now taking a much more patentee-friendly approach to assessing the priority claim in Europe. It is now the EPO’s assumption that the priority claim is valid unless evidence to the contrary is provided.
Background
Historically, the EPO has taken a very strict approach concerning the legal right to claim priority.
The EPO previously required all applicants named on a priority application, or their successors in title, to be named as applicants on the subsequent application claiming priority. This is known as the “all applicants approach”.
A transfer of the right to claim priority was only considered to be valid if it was effected prior to the filing of the application claiming priority. Retroactive assignments concerning the priority claim were not accepted, even if they were deemed valid under national law.
Famously, a key CRISPR patent owned by the Broad Institute was revoked in 2020 at the EPO under the “all applicants approach”. In this case, Dr. Marrafini was named as one of the applicants/inventors on the priority document, but neither Dr Marrafini nor his successor in title (Rockefeller University) were named as an applicant on the subsequent priority claiming PCT application. The patentee could not demonstrate that there was a transfer of the priority right to the other applicants named on the PCT application prior to the filing date of such PCT application. Therefore, the Board of Appeal at the EPO found the priority claim to be invalid. This led to relevant intervening prior art being cited against the claims, ultimately destroying the novelty of the claims and the patent was revoked.
Due to the EPO’s strong stance concerning the “all applicants approach”, the legal right to claim priority has been a hot area of attack for opponents during opposition proceedings at the EPO. Generally, if the applicants named on a priority application are different to the applicants named on the claiming priority and this has been challenged by the opponent, the onus has been on the patentee to confirm that there was a valid transfer of the priority claim prior to the filing of the application claiming priority, otherwise, the priority claim was not deemed valid.
Questions concerning the EPO’s approach to assessing the legal right to claim priority were referred to the EBA. These questions arose due to first-instance proceedings where the priority claim was found to be invalid because the inventor/applicant of the US priority application was only named as an applicant of the PCT application for the US only. The inventor/applicant was not named as an applicant for the remaining PCT contracting states and there was no transfer of the priority right from the inventor/applicant to the applicant named in the remaining PCT contracting states. Therefore, the common applicant was only effective for the US only. This is known as the “PCT joint applicants’ approach”.
Decision
The EBA considered the following questions in G1/22 and G2/22:
- Does the EPC confer jurisdiction on the EPO to determine whether a party validly claims to be a successor in title as referred to in Article 87(1)(b) EPC?
If question I is answered in the affirmative:
- Can a party B rely on the priority right claimed in a PCT application to claim priority rights under Article 87(1) EPC, in the case where:
- a PCT application designates party A as applicant for the US only and party B as applicant for other designated States, including regional European patent protections and
- the PCT application claims priority from an earlier patent application that designates party A as the applicant and
- the priority claimed in the PCT application is in compliance with Article 4 of the Paris Convention?
For the first question, the EBA confirmed that the EPO has the jurisdiction to decide whether a party is entitled to claim priority.
The EBA also surprisingly held that there is a strong rebuttable presumption that an applicant of a European patent application is entitled to claim priority. This has effectively shifted the burden of proof to the opponent to prove that the priority claim is invalid, which is effectively a reversal of the EPO’s approach.
The EBA also held that the EPO should “adapt itself to the lowest standards established under national laws and accept informal or tacit transfers of priority rights under almost any circumstances”. This confirms that the EPO should not have higher standards than at a national law level.
For the second question, the EBA held “The rebuttable presumption also applies in situations where the European patent application derives from a PCT application and/or where the priority applicant(s) are not identical with the subsequent applicant(s)”.
The EBA confirmed “In a situation where a PCT application is jointly filed by parties A and B, (i) designating party A for one or more designated States and party B for one or more other designated States, and (ii) claiming priority from an earlier patent application designating party A as the applicant, the joint filing implies an agreement between parties A and B allowing party B to rely on the priority unless there are substantial factual indications to the contrary”. Therefore, the EBA held that in the “PCT joint applicant’s” approach, there was an implicit agreement between the parties conferring the right to claim priority, absent indications to the contrary.
Practical implications
Before G1/22 and G2/22, the burden of proof was on the patentee to demonstrate that they were entitled to claim priority. However, the burden of proof has now been reversed to be on the opponent. Therefore, G1/22 is good news for patentees because it is now presumed that the priority claim is valid.
On the other hand, G1/22 and G2/22 makes an opposition relying on an invalid priority claim more difficult for the opponent. Opponents can no longer raise speculative doubts concerning the validity of the priority claim. Instead, opponents must now “demonstrate that specific facts support serious doubts about the subsequent applicant’s entitlement to priority”. This is likely to be much more difficult because such documents required to challenge the validity of a priority claim are most likely to be internal, possibly confidential, documents that may be difficult for an opponent to access. The high burden for an opponent to challenge the validity of the priority claim was confirmed in the recent Board of Appeal decision T 0419/16, where it was found that the opponent had “no substantial factual indications” to challenge the validity of the priority claim, and thus the priority claim was assumed to be valid.
Moreover, G1/22 and G2/22 appear to confirm that the EPO should accept retroactive transfers of the right to claim priority, if such a transfer is valid under the national law in question. However, it has yet to be seen how such a scenario would play out at the EPO, so we do not recommend relying on this approach to “fix” the priority claim.
Going forward, the “PCT joint applicants” approach, where the applicants are in common for the US only, appears to provide a valid priority claim in Europe, so long as there is no evidence to the contrary.
G1/22 and G2/22 do not explicitly address the common scenario where the applicants between the priority applicant and the priority claiming applicant are not in common for any state (not even the US) – which was the scenario for the Broad Institute’s key patent family discussed above.
However, in this scenario, the rebuttal scenario (in the patentee’s favour) would apply. This was confirmed early in 2024, where oral proceedings before the Board of Appeal were held on further patents held by the Broad Institute relating to the CRISPR/Cas9 system. These patents were initially revoked by the opposition division due to a lack of valid priority claim. However, in the appeal proceedings, the Board of Appeal sided with the patentee and found that Rockefeller had implied consent in claiming priority and therefore met the rebuttable presumption in G1/22 and G2/22, despite the opponent attempting to file evidence to the contrary.
Therefore, in summary, it appears that the EPO has now shifted towards a patentee-friendly approach regarding the priority claim. We are eagerly awaiting further case law to confirm what evidence the EPO considers to be “sufficient” to rebut the priority entitlement to provide further clarity for opponents.
