G1/26 – How does G1/24 apply to added matter under Article 123(2) EPC?

The Board of Appeal in case T0873/24 has made a new referral to the Enlarged Board of Appeal (EBA). The EBA is the European Patent Office’s highest authority on important matters of law relating to the European Patent Convention (EPC). The new referral, under reference G1/26, follows on from decision G1/24 and seeks to clarify whether the description of a European Patent application can be used to interpret the features of a claim when considering added matter under Article 123(2) EPC.

Article 123(2) EPC states that a European patent application may not be amended such this it contains subject matter which extends beyond the scope of the original application. Practice in this area is very strict, requiring that any amendment made must be directly and unambiguously derivable from the application as filed. G1/24 ruled that the description must always be consulted when interpreting claims. G1/26 seeks to ask how this applies when considering added matter.

The case in point in T0873/24 concerned a coated steel strip. The claims defined the steel in terms of the amount of titanium present and also the ratio of the amount of titanium to nitrogen present. The amount of titanium was expressed in the claims as a weight percentage however, the Ti:N ratio was unitless. According to the opponent, as the Ti:N ratio was not expressed in terms of a weight percentage, it did not exclude a ratio expressed in other ways, as a molar ratio for example. The Patentee referred to the description and took the position only a ratio in terms of weight percentages made technical sense. The extent to which the description can be used to interpret the claims was thus critical. Case Law following G1/24 was analysed and identified three possible interpretations:

i) The description should be used only to define the skilled person and the extent of their common general knowledge. Here, the fact that the claim did not express any units for the Ti:N ratio meant that the skilled person could interpret the claim as referring to a weight ratio or a molar ratio. In this case, because the description did not support a molar ratio, an objection under Article 123(2) EPC would arise.

ii) The description should not be used to either broaden or limit the scope of the claims. Interpreting the Ti:N ratio to be exclusively a weight ratio would be a limitation and so not permitted. As with case i), the ratio in the claim may then be either a weight ratio or a molar ratio. The latter, again not finding any basis in the original application, would give rise to an objection under Article 123(2) EPC.

iii) A ‘holistic’ approach should be taken based on the application as a whole. Under this approach, claims may be interpreted broadly or restrictively, as appropriate. The only mention of a Ti:N ratio in the application was a ratio expressed in weight percentages so this could be the only possible interpretation of the claim. In this case, Article 123(2) EPC would be met.

The referring Board reasoned that as the fate of the patent depended on which of the three interpretations was correct, it was appropriate to refer the case to the EBA. Three questions on the substance of the case were referred:

2 (a) Does the fact that the claims are the starting point and the basis for assessing the patentability of an invention generally preclude a feature which is only disclosed in the description or the drawings of a patent from being read into the meaning of a granted claim, in particular if this leads to a restrictive reading of terms used in the claim?

2 (b) If the answer to question 2(a) is no: is claim interpretation the result of both reading the claims and consulting the description and drawings as a unitary process and does the claim being the starting point and the basis for assessing the patentability rule out only those interpretations which can be derived from the patent as a whole but would clearly contradict the general technical understanding of the terms used in the claim?

3(a) When assessing compliance with Article 123 (2) EPC, must a term used in a claim be assessed against all interpretations that make technical sense to the skilled reader on the basis of the claim alone?

3 (b) If the answer to question 3(a) is no: is it sufficient that only the interpretations of the subject-matter of the claim established against the background of the patent specification as a whole are directly and unambiguously derivable from the application as filed?     

The referring Board also made comments concerning the admissibility of the referral per se. The EBA are not obliged to accept a referral and conventionally, have only accepted requests where the answers to the referred questions are determinative to the fate of the patent in suit. In the case of T0873/24 there were more than 100 auxiliary requests, many of which were not considered at all by the opposition division. The Board acknowledged that even with the EBA’s answers to questions 2(a), 2(b), 3(a) and 3(b), it was not impossible that the patent could nevertheless fall for lack of inventive step but argued that for reasons of procedural efficiency, the EBA’s input at this stage was essential. An initial question was thus asked:

May a decision be considered to be "required" for the purposes of Article 112(1) EPC, if the referring Board demonstrates that the point of law in question arises out of the context of the case pending before it and, in the circumstances of the proceedings, it is reasonable for the Board to examine it and decide on it next?

We await to hear whether the EBA will decide to accept the referral under G1/26. If they do, it will be interesting to see how the case law develops following G1/24.

Our Patent attorneys here at Mathisen and Macara have extensive experience of representing clients before the European Patent Office and would be delighted to answer any questions you have about this article, or any other aspects of European patent practice.