Recent UPC CoA ruling will lead to more file wrapper arguments even though it clearly wasn’t intended to strengthen them

Context: In an Alexion v. Amgen decision (December 23, 2024 ip fray article), the Unified Patent Court’s (UPC) Court of Appeal (CoA) opened the door — but far from the floodgates — to the equivalent of prosecution disclaimer arguments. The tone was different from the “couldn’t care less” attitude often displayed by German national courts when such arguments were raised.

Headnote 2:

The patent claim must be interpreted from the perspective of the person skilled in the art. The applicant’s assertions during the grant proceedings, and in particular the TBA’s [Technical Board of Appeal of the European Patent Office (EPO)] endorsement thereof, can be seen as an indication of the view of the person skilled in the art at the filing date.

Para. 42:

Moreover, in the proceedings before the TBA, Alexion submitted that the position of the three respective CDR sequences in SEQ ID NO:4 is sufficiently distant from the N-terminal signal peptide to dissuade the skilled person from doubting that this longer light chain would also 13 bind to C5 as required by the patent claims. This argument was accepted by the TBA, which accordingly concluded that the claimed antibody was sufficiently disclosed in the patent (T 1515/20, par. 35 and 36). This confirms that it is not sufficiently certain for the average skilled person that the longer light chain was an error.

What’s new: The CoA has not provided a new headnote on the admissibility of file wrapper arguments. But certain aspects of a recent decision will lead practitioners to raise even more such arguments in UPC cases going forward, not only because they want to win but simply because they owe it to their clients not to leave any reasonably identifiable stone unturned. Let’s look at what the CoA really said, what it clearly intended, and what will foreseeably happen until there is further guidance.