The problem, put simply, is that if a European application claims an invention more broadly than is disclosed in a priority application, can partial priority be allowed for what is disclosed in the priority application. If not, then the priority application, if it also publishes as a European application, becomes A54(3) prior art and knocks out the claimed invention. If partial priority is allowed, then the problem goes away (for reasons given here). The Enlarged Board in G 2/98 set out a proviso regarding when partial priority would be allowed under A88(2), which was only if it gave rise to a "limited number of clearly defined alternative subject-matters" (point 6.7). The meaning of this has been argued over for the past few years and a referral was made in August 2015 to the Enlarged Board in T 557/13, which asked the following question:
1. Where a claim of a European patent application or patent encompasses alternative subject-matters by virtue of one or more generic expressions or otherwise (generic "OR"-claim), may entitlement to partial priority be refused under the EPC for that claim in respect of alternative subject-matter disclosed (in an enabling manner) for the first time, directly, or at least implicitly, and unambiguously, in the priority document?The referral, which was numbered G 1/15, generated a lot of interest, as evidenced by the number of amicus briefs filed, as well as the number of comments received on this blog. Most of the briefs recommended a 'no' answer to question 1, which would cause the problem to go away. Following a hearing in June last year, the Enlarged Board issued an order that gave the following answer to the question:
Under the EPC, entitlement to partial priority may not be refused for a claim encompassing alternative subject-matter by virtue of one or more generic expressions or otherwise (generic "OR"-claim) provided that said alternative subject-matter has been disclosed for the first time, directly, or at least implicitly, unambiguously and in an enabling manner in the priority document. No other substantive conditions or limitations apply in this respect.As far as I could see, this made the problem go away. There would no longer be any issue over partial priority and possible collisions between a priority document and a European application. Simply answering the question, however, was not the full story. The Enlarged Board has now issued their full reasoned decision, which has just appeared on the EP register here.
The decision goes over all of the arguments put forward along the way, which regular readers will already be well aware of (see the links above to previous posts). What the key question concentrates on is what was meant in G 2/98 by "a limited number of clearly defined alternative subject-matters", and how this could be aligned with the EPC and with the famous FICPI Memorandum that apparently expressed the legislative intent behind A88(2). I have tried to make it clear on this blog that the examples in the Memorandum must be consistent with any interpretation of A88(2), and partial priority should be assessed accordingly. Others, including the respondent in G 1/15 have effectively argued that this does not need to be the case.
The reasoning in G 1/15, as you would expect, starts from basic principles of priority, and develops towards the principles of partial and multiple priorities, leading up to the Memorandum, which defined examples where multiple priorities should be allowed in a single claim. The Enlarged Board thankfully make it quite clear that the Memorandum is indeed consistent with A88 and the Paris Convention, and then lead up to the inevitable consequence that the proviso in G 2/98 "cannot be construed as implying a further limitation of the right of priority" (point 5.3). This is enough in itself to reach a 'no' answer to question 1, but the Enlarged Board go on to lay out in clear terms how partial priority should be assessed. This is laid out at the end of the reasons for the decision, at points 6.4 to 6.7, which state:
In assessing whether a subject-matter within a generic "OR" claim may enjoy partial priority, the first step is to determine the subject-matter disclosed in the priority document that is relevant, i.e. relevant in respect of prior art disclosed in the priority interval. This is to be done in accordance with the disclosure test laid down in the conclusion of G 2/98 and on the basis of explanations put forward by the applicant or patent proprietor to support his claim to priority, in order to show what the skilled person would have been able to derive from the priority document. The next step is to examine whether this subject-matter is encompassed by the claim of the application or patent claiming said priority. If the answer is yes, the claim is de facto conceptually divided into two parts, the first corresponding to the invention disclosed directly and unambiguously in the priority document, the second being the remaining part of the subsequent generic "OR"—claim not enjoying this priority but itself giving rise to a right to priority, as laid down in Article 88(3) EPC.Just to make it clear, here is a simple flowchart I have created that defines the process to follow when considering whether partial priority should be allowed.
This also corresponds, logically and exactly, to the scheme described in the Memorandum (see point 5.2 above): "If a first priority document discloses a feature A, and a second priority document discloses a feature B for use as an alternative to feature A, then a claim of the application directed to A or B will in fact consist of two distinct parts A and B respectively, each complete in itself...", and further: "... it would be appropriate to claim a partial priority in situations corresponding to the "OR"-situation under "Multiple Priorities", the European patent application itself taking the place of the second priority document".
The task of determining what is the relevant disclosure of the priority document taken as a whole, and whether that subject—matter is encompassed by the claim in the subsequent application, is common practice in the EPO and among practitioners of the European patent system and as such should not pose any additional difficulty. Nor does it create uncertainty for third parties, as argued by the respondent and in some amicus curiae briefs. Although it can be a demanding intellectual exercise, the decisions reached in cases T 665/00, T 135/01, T 571/10 and T 1222/11 all show that it can be carried out without any need for additional tests or steps.
From this analysis it follows that the assessment of entitlement to partial priority right does not show that any additional requirements are needed.