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[17/06/2026]

Following on from the landmark decision G 1/24, which confirms that the description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention, the question arises as to whether this approach is also appropriate to assess the admissibility of amendments (under Articles 123(2) and 76(1) EPC).

The EPO consistently applies the ‘Gold Standard’ defined in decision G 2/10:  An amendment is regarded as introducing subject-matter which extends beyond the content of the application as filed and, consequently, as inadmissible, if the overall change in the content of the application (whether by way of addition, alteration or excision) results in the skilled person being presented with information which is not directly and unambiguously derivable from that previously presented by the application, even when account is taken of matter which is implicit to a person skilled in the art.

However, it is still necessary to interpret this ‘information presented to a skilled person’: an amendment to the claims might be considered to cover embodiments that have no basis in the application as filed, or, conversely, to be implicitly limited when read in the light of the description.

In the case that led to the referral (T 873/24), a ratio was indeed added without specifying its unit, even though the description clearly defines that it is a ratio by weight.

In its referring decision of 3 June 2026, the Technical Board of Appeal identifies three divergent approaches in case law:

1/ “consulting the description only to define the skilled person”

2/ “no broadening or limitation of claims based on the patent specification”

3/ “holistic approach”

According to the first two approaches, the amendment would lead to an extension of the subject-matter in breach of Article 123(2) EPC, whereas according to the third approach, the amendment would be allowed.

Consequently, the Board of Appeal has decided to refer the matter to the Enlarged Board of Appeal, and submits the following questions:

1. 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?

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?

In essence, if the Enlarged Board of Appeal considers the referral admissible, it shall decide on whether, when assessing the scope of the subject-matter, all possible interpretations of a term should be taken into account, or only those arising from the application as a whole.

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