Art. 123(2) EPC: A practical example
Art. 123(2) EPC: A practical example
During prosecution of a European patent application, any amendment to a patent claim is governed by article 123(2) of the European Patent Convention (EPC). This article applies both in the Examination phase of a European patent application, as well as in the opposition and/or appeal phase of a granted European patent. It furthermore applies to all sorts of amendments, including amending a claim by removing a feature; amending a claim by replacing a feature; amending a claim by adding a feature; amending a claim by adding a disclaimer; and amending the description. One could say that Art. 123(2) EPC is one of the most crucial articles of European patent law. Before assessing the novelty and inventive step of the proposed amended claim, the EPO typically first decides whether a proposed amendment is allowable under Art. 123(2) EPC.

The legal wording of Art. 123(2) EPC is rather short: “the European patent application or European patent may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed”. (emphasis added)

The EPO is usually very strict when it assesses the criterion of “extend beyond”, following the case law on the subject. I will explain a practical example of the amendment type “adding a feature to a claim”.

Intermediate generalization or basis in application as filed?
It is well established case law that when several features are disclosed in combination with each other in the application as filed it is not normally permitted to extract a subset of these features and add them to a claim, without also adding the other feature(s). This would be an “intermediate generalization”. While this criterion sounds quite simple, in practice it is not. So what does this legal wording mean in practice?
After the European Patent EP0622481B1 was granted an opposition was filed, followed by an appeal against the decision of the opposition decision: case T0025/03. During this appeal, the patentee wanted to amend granted claim 1 by adding a feature to the claim. The patentee argued that basis for this feature could be found in Figure 4 of the application, which is copied below in a simplified form:


The patentee wanted to limit the claim in such a way that it included the wording ‘decide whether condition A is met, by establishing that question 2 is answered in the affirmative and question 3 in the negative’.
According to the Board of Appeal, this was not allowed under Art. 123(2) EPC. According to Figure 4, first question 2 has to be answered in the affirmative, before question 3 is asked. This sequence for the questions was not reflected in the proposed amendment. Hence a feature, namely: the sequentiallity, which was disclosed in figure 4 in combination with the introduced features ‘decide whether condition A is met, by establishing that question 2 is answered in the affirmative and question 3 in the negative’ was not included in the proposed amendment. Therefore the proposed amendment was not allowable as it extended beyond the original disclosure.

As this limitation request was only filed at the very last minute as a last resort, during the oral hearing in front of the Board of Appeal, the non-allowance of this limitation ultimately led to a loss of the patent.

Take home message
This practical example teaches us that one has to be very careful when amending claims of European patents and European patent applications. Even though it might seem a formality, not complying with Art. 123(2) EPC can lead to a loss of a valuable patent.

Of course, every case is unique and many alternative scenarios can be taught of in which Art. 123(2) plays a role. Questions? Do not hesitate to contact me.