UPC Engages with Prosecution History in Claim Interpretation

A recent decision from the Düsseldorf Local Division in UPC_CFI_351/2024 saw the Court consulted the prosecution history to resolve a question in claim interpretation. Most European courts do not rely on the prosecution history at all, such that prosecution history estoppel is not a recognised concept in Europe. This said, the UPC has already opined that comments made during prosecution may inform the courts of the state of mind of the person skilled in the art. On this occasion, whilst interpretation of the scope at the UPC generally focuses on the claim in light of the description and drawings, the Court was confronted with arguments by the defendant that, during prosecution, a claim term had been “redefined”. Specifically, the defendants argued that in the patentee’s response to the Communication under Rule 71(3) EPC, they had confirmed that “bottom side” was to be interpreted as “bottom plane”.

Based on the prosecution history, the Court denied that this was the case, noting that the patentee had in fact argued against such an interpretation of the term “bottom side”. As a result, the Court dismissed an added matter attack on the basis of the alleged redefinition and upheld the patent. Whilst this case clearly does not herald the advent of a file wrapper estoppel, it is nevertheless remarkable that the Court did not simply refer to the patent as granted to assess its validity but instead engaged with file wrapper estoppel-type arguments by the defendant – even if these were held to be without merit.