As I mentioned in my July 2013 post on the Nestec case at the EPO, in my view the only way to resolve the poisonous priority issue would be for a referral to be made to the EPO Enlarged Board. In the Nestec case, the issue unfortunately did not get to the stage of discussing partial priority because the patent was revoked on other grounds. It was, however, inevitable that the same issue would arise in another case, and the clear inconsistency between the Board of Appeal decisions in T 1222/11 and T 1877/08 (among others) about how to interpret G 2/98 would have to be resolved somehow. That case has now appeared.
In appeal proceedings for T 557/13 (Infineum), relating to EP0921183 (see the EP register here), the Board of Appeal have recently decided to refer one or more questions to the Enlarged Board of Appeal. As yet, the only indication of this is the minutes of the oral proceedings that were held on 17 December 2014, and no questions have yet been decided on, although there are some suggestions. The questions will, however, most certainly be about the extent to which partial priority can be claimed and what effect this has on priority applications becoming prior art under Article 54(3) EPC.
The appeal relates to a decision by the opposition division to revoke Infineum's patent (which resulted from a divisional application) based on the claims not being fully entitled to their priority and, as a result, the published parent application becoming Article 54(3) prior art. The opposition division cited G 2/98, and referred to the apparent requirement for the elements of a claim having to be "separable alternative embodiments" (see point 3.1.2 of the ground of the decision; my emphasis). Since this was not the case with claim 1 as granted, the OD decided that the claim was not entitled to priority for its entire scope and was only entitled to the application's filing date. T 1877/08 was cited in support, but the contrary decision in T 1222/11 was not published until the following year. During appeal proceedings, the proprietor made extensive arguments (see here for the grounds of appeal) about the poisonous priority issue, and why it should not happen, but did not refer to T 1222/11 until later on. They did, however, cite one of my posts (this one), which "discusses the issues at the heart of the case and highlighted some of the differing views prevalent among practitioners" (page 6 of the ground of appeal), and which apparently provided them with suggestions for a few helpful arguments.
T 1222/11 was first raised in the proprietor's further submissions in May 2014, together with some further articles on the issue. The Board of Appeal then issued a summons and, in their preliminary opinion, stated that "the issue of novelty apparently may hinge on the question of whether or not [...] the patent in suit can validly claim a right of priority as regards the use of the product of Example 1 as cold flow improver, considering in particular that said use is merely embraced by the more generic definition of the invention according to Claim 1 at issue, rather than being clearly defined as a distinct alternative of the invention defined in Claim 1" (point 4.2.2 of the provisional opinion dated 26 November 2014). The issue in question is therefore clearly one that would be decided differently, depending on whether the approach according to T 1222/11 or T 1877/08 is taken.
The proprietor has already suggested some questions that could form the basis for a referral:
Where a claim of a European patent or patent application encompasses more specific subject matter disclosed in an earlier application from which priority is claimed, for example because the claim in question contains generic term(s) or generic formula(e) encompassing both the subject matter disclosed in the priority application and alternative(s) thereto:
1. Is the expression "provided that it gives rise to the claiming of a limited number of clearly defined alternative subject matters" from Point 6.7 of Enlarged Board opinion G2/98 to be applied as the legal test for entitlement to partial priority under Article 88(2) and (3) EPC?
2. If the answer to 1 is 'yes', how is the test from Point 6.7 to be applied in this situation, and in particular, how is a claim containing generic term(s) or generic formula(e) to be interpreted as relating to a limited number of clearly-defined alternative subject matters?
3. If the answer to 1 is 'no', what is the legal test for partial priority of a claim containing generic term(s) or generic formula(e), and how is it to be applied to such a claim?
In the situation defined above, where:
(i) the European patent was, or the European patent application is, a divisional application ("Divisional") and the claim in question fails the legal test for partial priority as clarified above;
(ii) the parent European patent or patent application ("Parent") claims the same priority and, as published, discloses specific subject matter also disclosed in the priority application and encompassed by the claim of the Divisional; and
(iii) the Parent and Divisional designate the same EPC contracting states:
4. Does Article 76(1) EPC nevertheless prevent different effective dates being attributed to the claim of the Divisional and the priority-entitled specific subject matter in the Parent?
5. If the answer to 4 is 'no', is the term 'European patent applications' in Article 54(3) EPC to be interpreted as extending to the Parent application, thereby rendering the Divisional lacking in novelty over its Parent ?Answering these questions would resolve the issue, but we may have a little while to wait before we get the answer.
UPDATE 13 August 2015: The interlocutory decision in T 557/13 is now out. See my post on the subject here.