LD Milan: The UPC takes a fresh look at prosecution history estoppel (UPC CFI 727/2024, UPC CFI 493/2025)

In this matter, Local Division Milan had to construe features defining, inter alia, positioning means in an opened state of a centring device for an injection-moulding or die-casting forming tool. The claimant advocated a broad interpretation according to which an entire intermediate phase during which the transition from the opened state to the closed state takes place should be regarded as part of the “opened state”. The defendants put forward a narrower interpretation, involving a second rolling body row touching an edge.

Crucially, during EPO prosecution the Claimant had submitted that it was “essential” or “decisive” (in the German original: “entscheidend”) that the second rolling body row abuts the edge. The communication of intention to grant the patent came in response to this submission. On this basis, the Local Division did not follow the broad interpretation of the claimant.

In more detail, the Local Division indicated that, “in view of legal certainty, the complete turnaround in the statements made by the applicant/proprietor must be taken into account”. Later in the section 4 – claim construction, the Decision reads that “The applicant’s assertions during the grant proceedings can be seen as an indication of the view of the person skilled in the art at the filing date” and that “Although statements made by the patent proprietor during examination proceedings before the EPO are not binding, they may nevertheless provide further guidance on interpretation as they reflect the possible opinion of the person skilled in the art”.

This decision appears to move European practice closer to a form of file-wrapper estoppel familiar from US law. Traditionally, European courts have given limited weight to statements made by a patent proprietor during examination and have not treated them as binding for claim interpretation. Here, however, while confirming that such statements are not binding, the Division relied on them as the main guidance for construing the claim.

The Decision seems to go beyond the earlier decision of Court of Appeal on Estoppel Alexion Pharmaceuticals v Samsung Bioepis (UPC_CoA_402/2024 and UPC_CoA_405/2024, 20 December 2024), which had already considered that statements made during prosecution could be used as an indication of the view of the person skilled in the art at the filing date.

It will be interesting to see if the Court of Appeal follows this view. In such a case, it will become (even more) critical to avoid statements during prosecution which narrow the claims.