An EPO Case Law Round-Up: Added Matter


The EPO is well-known for its strict approach to assessing amendments under the added matter provision of Article 123 of the European Patent Convention. This often creates complex legal scenarios which do not exist in other territories, such as the United States.

Added matter is therefore a hot topic in both prosecution and opposition proceedings in Europe.

This article provides an overview of the most impactful EPO case law in this space, focussing on three key areas:

  1. Intermediate generalisations
  2. Treating the application as a ‘reservoir’
  3. Selections from lists

Whilst there is some overlap between these three areas, we will discuss them separately for ease.

1. Intermediate Generalisations

What does this mean? An intermediate generalisation refers to the situation where a feature is extracted in isolation from a combination of features (e.g. from an example), and added to a claim as an amendment. The amended claim forms an intermediate generalisation of subject-matter, and is generally not allowed under Article 123(2) EPC.

What is the historic guidance? Generally, these types of amendments have only been allowed where the isolated feature does not have any clearly recognisable functional or structural relationship with the original combination of features[1]. The common test used by the EPO when assessing these amendments, is whether the extracted feature is ‘inextricably linked’ with the combination of features in the original disclosure[2], i.e. incidental to the proper functioning of a specific embodiment[3], and that the overall disclosure must justify the generalising isolation of the feature and its introduction into the claim.

What is the case law saying now? There has not been much game-changing case law in this area, following an apparent consolidation by the Board in T 1906/11. Here, the EPO said that the most relevant question in the assessment of intermediate generalisations is whether a skilled person faced with the amended version of the application or patent would derive any additional technically relevant information over the disclosure of the original version. Only if this type of information is derived is there a contravention of Article 123(2) EPC. This was revisited in 2018 where it was confirmed that this information would be derived if the original disclosure conveyed the teaching, explicit or implicit, that all the features of that combination had to be present together in order for a specific technical effect to be obtained[4]. In this case, claiming only some of those features would present the skilled person with additional technical information.

2. Treating the application as a ‘reservoir’

What does this mean? This area of case law does not so much relate to a specific type of amendment, but is a common term used by the EPO when features disclosed in the original application as optional are combined to create a ‘new’ combination not originally disclosed in the application (i.e. a combination of features that is not “individualised” in the original application). This is particularly relevant if the features are described in relation to separate embodiments.

What is the historic guidance? The EPO considers that the content of the application as filed must not be treated as a ‘reservoir’ of features that applicants can pick and choose from to make an amendment[5]. In order to combine features, there must be a ‘pointer’ or ‘indication’ to the selection or combination of particular features, for example a disclosure that a feature is ‘preferred’[6]. The fact that a feature or combination is part of an experimental example can, in some instances, indicate that it is preferred[7].

The guidance is not always consistent. In T 1241/03, claims directed to a formulation comprising compounds in specific concentrations did not need to have literal basis in a single passage of the application as filed – here, basis was taken from different sections of the description. However, in T 1150/15, which related to the medical use of a compound defined by a Markush formula, the Board of Appeal did not take such a relaxed approach and rejected a combination of preferred sub-groups because there was no basis for the specific combination in one place. This interpretation appears strict, although a large number of elements did have to be combined to arrive at the claim scope.

What is the case law saying now? More recent case law has addressed this issue head-on, but unfortunately without consistency.

In T 1442/16, the Board held that features from different embodiments are not necessarily combinable, putting emphasis on the literal meaning of the word ‘embodiment’. Here, ‘embodiment’ was held to mean separate and non-combinable with other ‘embodiments’.

T 0524/17 provides a divergent view on this. In this case, the Board held that “the expression ‘embodiment’ does not relate to such a specific set of features, but rather refers to preferred features of the invention described therein…”. In the context of the case, the expression ‘in one embodiment’ was found to refer to a general teaching. In this case, features from separate embodiments could be combined.

It will be interesting to see what further case law arises on this point, in view of its significance to drafting a patent application.

3. Selections from lists

What does this mean? If an amendment involves more than one selection of features from a list (or from lists), the amendment may not meet the added matter requirements of the EPO. This is perhaps one of the more complicated and evolving areas of added matter case law – and a frustration for many applicants.

What is the historic guidance? A ‘selection’ generally refers to the isolation of a feature from an embodiment or list, where there is no ‘pointer’ to do so (see section 2 above). Amending a claim to include a feature involving a single ‘selection’ is generally considered acceptable, however EPO case law states that amending a claim to include one selection from a first list and another selection from a second list (a two-fold selection) is not permissible[8]. It is also not permissible to amend a claim to include two selections from the same list[9].

What is the case law saying now? Two back-to-back decisions from the EPO Board of Appeal looked at the situation where selections are made from a list of converging features, i.e. a list where each of the narrower elements is fully encompassed by all the preceding less preferred and broader options. Does the isolation of a feature from such a list constitute a selection? In T 2273/10, the Board considered there to be no basis in the application for arbitrarily combining most preferred elements with less preferred elements taken from a list of converging alternatives. The fact that some features were ‘preferred’ did not constitute a pointer to said features. This seemed to suggest that the EPO would treat a converging list in the same manner as a non-converging list. However, in another case T 2237/10, the Board said that such amendments could be allowable but only when the features incorporated into the claim were derived from the original dependent claims rather than from the description. This is because “the now-claimed combination was foreseen by means of dependent claims in the application as originally filed”.

The converging list scenario was re-visited very recently in T 1621/16. In this case, the Board held that selection from a convergent list is different in principle from selection from a non-convergent list. Similar to deleting items from a list (i.e. shrinking the list), selecting one item from a list of converging alternatives leads to subject-matter based on a more or less restricted version of that feature, and can therefore be allowable. However, the Board emphasised that selections from multiple convergent lists may not necessarily be allowable under Article 123(2) EPC. See our more detailed review on this case here.

Regardless of whether the lists are convergent or non-convergent, where there is an indication that a feature is ‘preferred’ the isolation of said feature may not be considered a ‘selection’ (as discussed above). In some situations, the fact that certain features are present in the experimental data of a patent or patent application can be used to illustrate that the features are preferred[10].


As is evident from the above, added matter case law at the EPO, even in just the three areas discussed, is complicated and constantly evolving. However, it is important to remember the over-riding “gold standard” for assessing added matter. The question being what a skilled person would “…derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing, from the whole of these documents as filed."[11]. Ultimately, regardless of the specific situation in question, this is the standard that must always be met.

If you have any questions on any aspects discussed in this article, please do not hesitate to contact us.

[1] T 1067/97

[2] T 0714/00

[3] T 1500/07

[4] T 0802/13

[5]T 0296/96

[5] T 0296/96

[6] T 0686/99 and T 1206/07

[7] T 0083/04 and T 0197/08

[8] T 0727/00

[9]T 1374/07

[10] T 0083/04 and T 0197/08

[11] G 2/10