G 1/22 & G 2/22 – substantial changes to assessment of priority claim validity at the EPO

The EPO’s Enlarged Board of Appeal has published its much-awaited decision on G 1/22 and G 2/22 regarding the validity of priority claims.

As a brief introduction to the matter at hand, the decision relates to consolidated cases T 1513/17 and T 2719/19 concerning the same proprietor – Alexion Pharmaceuticals, Inc. (‘Alexion’). In both cases, the Opposition Division had found the priority claims for the patents in question to be invalid. This resulted in the patents being revoked during opposition proceedings on the grounds that they lacked novelty over intervening prior art.

In both cases, priority was claimed to a US provisional patent application filed in the name of three inventors. However, the subsequent PCT applications (from which the European applications were derived) named the three inventors as applicants for the USA only. For all other designated states, Alexion and the University of Western Ontario (‘UWO’) were the named applicants.

During the opposition proceedings, the opponents had successfully argued that the European applications’ priority claims to the US provisional application were invalid, as only one of the three inventors had assigned their priority right to Alexion and UWO prior to the filing of the PCT. Alexion appealed these findings.

The Technical Board of Appeal decided to refer the following questions to the Enlarged Board:

I. 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?

II. If question I is answered to the affirmative Can a party B validly rely on the priority right claimed in a PCT-application for the purpose of claiming priority rights under Article 87(1) EPC in the case where:

  1. 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 protection and
  2. the PCT-application claims priority from an earlier patent application that designates party A as the applicant and
  3. the priority claimed in the PCT-application is in compliance with Article 4 of the Paris Convention?

The answers from the Enlarged Board were:

“I. The European Patent Office is competent to assess whether a party is entitled to claim priority under Article 87(1) EPC.

There is a rebuttable presumption under the autonomous law of the EPC that the applicant claiming priority in accordance with Article 88(1) EPC and the corresponding Implementing Regulations is entitled to claim priority.

II. 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).

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”.

With regard to question I, the answer is relatively straightforward and perhaps not surprising. In short – yes – the EPO is competent to assess whether a party is entitled to claim priority under Article 87(1) EPC. In their reasoning (85), the EPO noted that “[s]ince the creation, the existence and the effects of the priority right are governed only by the EPC (and by the Paris Convention through its relationship with the EPC), priority rights are autonomous rights under the EPC and should be assessed only in the context of the EPC, regardless of any national laws”.

However, in their decision making and in answering question II, the Enlarged Board found that there is a “rebuttable presumption” that the applicant claiming priority is entitled to said priority. In the PCT situation discussed above, it was held “the joint filing implies an agreement between parties A and B” whereby party B can rely on the priority, even if party A had not formally assigned the priority right beforehand, “unless there are substantial factual indications to the contrary”.

This decision represents a substantial change over the previously well-established case law. In T 205/14, the board had found that an equally high standard of proof as that required by Article 72 EPC (“An assignment of a European patent application shall be made in writing and shall require the signature of the parties to the contract”) was required to establish transfer of priority right. T 1201/14 had gone further still, with the board stating that proof of a valid transfer of the right of priority must be “beyond reasonable doubt” (rather than proof based on the “balance of probabilities”, as relied upon in T 205/14).

The new finding of a rebuttable presumption of valid priority will likely have a significant effect on opposition proceedings like those discussed above. The need to provide specific and substantial facts will make it difficult for opponents to attack the validity of priority claims under similar circumstances going forward. The burden that this decision places on the opponent will likely mean that these arguments will be off limits for all but the most tenuous priority claims.

The order from G 1/22 and G 2/22 changes the practice of the EPO on validly claiming priority and may come as a relief to some applicants. We welcome this shift to a more pragmatic assessment of entitlement to priority.

To continue the conversation please contact the author, or your usual Barker Brettell patent attorney.