Amending a patent application or a patent that has been granted, in such a way that it contains subject-matter which extends beyond the content of the application as originally filed, is a ground for revocation of said patent. This ground for revocation, which has not been explored a great deal in the past, has been dealt with in a case pitting Thermomix against Lidl.

In a previous Blog IP entry, we spoke of added matter as a ground for refusal of a patent application in the administrative jurisdiction (see here). As we indicated in that post, the amendment of a patent application during, in such a way that the subject-matter extends beyond the content of the application as filed, are also grounds for revocation of a patent that has already been granted. This is expressly established in article 102.1 c) of the Patents Law and article 138.1 c) of the European Patent Convention (EPC). It should be underscored that sections d) of those articles state that the patent may also be revoked where the protection conferred by the patent as granted has been extended.

The aim of “added matter” as a ground for revocation is to ensure the legal certainty of third parties and prevent the applicant improving its initial position by amending the application or granted patent. This is why it is extremely important for the application to be well drafted and complete from the outset.

Despite what its literal name may suggest, added matter does not only occur due to the addition of new features, but also as the result of the alteration or excision (i.e. deletion) of already disclosed features. This means that matter may be considered to have been added even if the scope of protection has not been extended. However, in practice, it is very difficult to assess, especially because of the lack of legal precedents in Spain and the absence of case law by the Supreme Court laying down the criteria that need to be followed in the assessment of whether an amendment involves the addition of subject-matter with respect to the application as originally filed.

However, the Madrid Provincial Appellate Court (judgment by Panel 28 no. 144/2013, of May 3, 2013) and Barcelona Provincial Appellate Court (judgment by Panel 15 no. 593/2019, of March 29, 2019) have based their judgments on various decisions by the European Patent Office when determining whether a specific amendment should be considered added matter as set out in article 123.2 EPC, from which the following general criteria transpire:

  • Adding matter is a factual question that needs to be addressed in view of the specific circumstances of each specific case.
  • In order to evaluate whether a limitation complies with the prohibition to add matter, the content of the original application as filed must be assessed. The content of the application as filed is determined by the information disclosed in the application as a whole, whereby it is necessary not just to bear in mind the claims but also the remaining parts of the application, the description and drawings. The content of the application must be interpreted in light of general common knowledge, i.e. the general knowledge of the expert skilled in the art at the time the application is filed.
  • An amendment is admissible if the subject-matter resulting from the amendment is directly and unambiguously derivable from the application as filed. This occurs where there is no doubt at all this subject-matter is disclosed in the application as filed (either explicitly or implicitly). Conversely, it is insufficient for the subject-matter of the patent resulting from the amendment to be consistent with the description of the application or to fall within the terms of a “plausible interpretation”.
  • It is necessary to differentiate between what is implicit in the application and what is obvious based on its content, both explicitly and implicitly. Amendments “that are obvious” do not meet the requirements established and infringe the added matter prohibition. Implicit means what an expert skilled in the art considers has necessarily been included in the application as a whole, even if it is not expressly indicated. That is, content that although not expressly mentioned in the application is clearly and unequivocally a result of what has been explicitly mentioned.

These guidelines may in principle seem very clear, but they are very difficult to apply to each specific case, as can be seen in the recent Thermomix® case pitting Vorwerk against Lidl in relation to the sale of their food processors. In this case, Barcelona Commercial Court number 5 concluded that there has been no added matter and confirmed the validity of Vorwerk’s patent.

However, the recent judgment by the Barcelona Provincial Appellate Court (judgment by panel 15 no. 14/2022, of January 13, 20200), did consider that Vorwerk’s Thermomix® patent violated the added matter prohibition. Indeed, the court reached the conclusion that during prosecution the applicant had introduced features that had not been disclosed in the initial application –either expressly or, in the court’s opinion, implicitly–. When comparing the patent application with claim 1 of the patent granted, it held that the initial application had not disclosed a weighing device controlled by an independent circuit on the same control board that controlled the stirring and heating functions, and that consequently an expert skilled in the art could not deduce this characteristic directly and unambiguously from the original application. In short, according to the court, by including this amendment during the processing, the expert skilled in the art was being given new information that was not contained in the application.

However, the court considered that there been no added subject matter through so-called “intermediate generalization”; that is, the prohibition on amended claims that are based on extracting a specific feature in isolation from an originally disclosed combination of features. Lidl underscored that during the patent validation process in Spain, a feature of the initial application had been deleted: the indication that the switch releases the current “at least for certain functions of the control board”, leading to an extension of subject-matter. However, according to the court, in light of the function of the switch contained in the description of the patent, no generalization had taken place.

In view of the above, the Barcelona Provincial Appellate court revoked Vorwerk’s patent, meaning that Lidl could not have infringed it. However, the judgment may be appealed before the Supreme Court.

Until relatively recently, added matter was a rara avis in patent litigation and very few proceedings involved an attempt to exploit this defect to revoke the patent. For several years now, parties are increasingly daring to bring this issue before the courts and we believe that the Thermomix® case could help to make this defense – which has for so long taken a back seat – more popular. In this context, it is extremely important for the Supreme Court to issue a decision on how rules regarding the addition of content should be applied in practice.


Cintia Bernhardt and Polina Shishkunova

Garrigues Intellectual Property Department