In recent years the issues of poisonous priority, poisonous divisonals and partial priority have increasingly arisen during the prosecution of European patent applications and before the UK courts, such as in the 2013 Nestec v Dualit judgement from the High Court (see here). The issue has now been referred to the Enlarged Board of Appeal at the European Patent Office as G1/15 and, therefore, some form of clarification can be expected within the next year or so. The Enlarged Board of Appeal have provided third parties with the opportunity to provide comments on the matter by 1 March 2016.
Stay of proceedings
The President of the EPO has announced the stay of all proceedings before EPO examining and opposition divisions that depend entirely upon the outcome of the decision of the Enlarged Board of Appeal. The examining and opposition divisions are to inform all parties in such proceedings and withdraw any communications setting time limits for response.
Proceedings to be stayed are those in which:
- An invention to which a claim is directed is not novel and/or inventive in the light of the prior art (including applications belonging to the same family, and the application from which priority is claimed), if the claim is not entitled to partial priority;
- The claim in question encompasses, without spelling them out, alternative embodiments having all the features of the claim (known as a generic “OR”-claim), i.e. is directed to subject-matter defined by one or more generic expressions, such as a chemical formula, a continuous range of numerical values or a functional definition;
- The priority document discloses only one or more (specific) embodiments covered by the claim in question (i.e. the claim is a generalisation of the disclosure of the priority document), but not the subject-matter of the entire claim itself; and
- The outcome of the proceedings depends entirely on how the Enlarged Board answers the points of law referred to it.
Please contact your usual Boult Wade Tennant adviser if you think that one of your applications should be stayed.
Poisonous and partial priority
The basic concept of poisonous priority is that a first filed European application “A” can be used to destroy the novelty of a second European application “B”, which claims priority from application A. The situation arises if the claims of application B are broader than the subject matter disclosed in application A. Application B may therefore have an invalid priority claim to application A. If application A publishes, it may become novelty-destroying prior art against application B. The issue can also arise with a divisional applications derived from application B, as if the divisional application contains broad claims and is found to have no valid priority claim to application A then both application A and B could be cited as prior art against the divisional application.
Partial priority was set out in detail in the Enlarged Board of Appeal decision G 2/98. As an example, application A discloses subject matter X and application B discloses subject matter X+Y. If the claim of application B is set out as “X OR Y” then the claim will have partial priority from application A; it can enjoy priority to application A for feature X but no priority for feature Y. If the claim of application B is set out as “X AND Y” then the claim will not have priority; application A did not disclose X and Y together so the first time this was disclosed was upon filing of application B.
G1/ 15: The referred questions
The questions have been formulated to directly address some of the issues raised in G 2/98 and the link between partial and poisonous priority. In particular, the issue at hand is where the claim of a divisional of application B contained a generic expression and the subject matter of application A contained a specific alternative within the generic expression. However, the claim does not explicitly define the alternatives in an “OR” statement so it is difficult to define the alternate subject matters within the generic expression. Should the claim of the divisional of application B enjoy partial priority from application A? Can application B be cited as novelty destroying prior art against the divisional application (i.e. “poisonous divisionals”).
The Board of Appeal thought that there had been a non-uniform approach to the application of G 2/98 and therefore that the following questions needed to be answered by the Enlarged Board of Appeal:
- 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?
- If the answer is yes, subject to certain conditions, is the proviso “provided that it gives rise to the claiming of a limited number of clearly defined alternative subject-matters” in point 6.7 of G 2/98 to be taken as the legal test for assessing entitlement to partial priority for a generic “OR”-claim?
- If the answer to question 2 is yes, how are the criteria “limited number” and “clearly defined alternative subject- matters” to be interpreted and applied?
- If the answer to question 2 is no, how is entitlement to partial priority to be assessed for a generic “OR”-claim?
- If an affirmative answer is given to question 1, may subject-matter disclosed in a parent or divisional application of a European patent application be cited as state of the art under Article 54(3) EPC against subject-matter disclosed in the priority document and encompassed as an alternative in a generic “OR”-claim of the said European patent application or of the patent granted thereon?
Please contact your usual Boult Wade Tennant adviser should you have any questions.