Sunstar Engineering Europe v CeraCon (CFI, 8 August 2025)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By order of 8 August 2025 (UPC_CFI_745/2024 and counterclaim UPC_CFI_200/2025), the Mannheim Local Division (Presiding Judge Tochtermann, Judge Böttcher as judge rapporteur, Judge Bessaud and technically qualified Judge Gaillarde) rejected CeraCon’s request for review of the judge rapporteur’s order of 6 June 2025, which had refused leave to add to its counterclaim for revocation of EP 4 108 413 a lack of novelty attack based on EP 3 868 480 A1. The order matters to any defendant who comes across prior art late: diligence is shown through the initial search.

Question

Could the judge rapporteur refuse, under Rule 263 RoP, the addition of prior art found by chance two months after the counterclaim was filed?

Decision

The panel holds that the impugned order applied the correct standards: Rule 263 RoP confers a discretion, which also governs amendment of a counterclaim, and requires the parties’ interests to be weighed against the public interest in efficient proceedings. Where prior art could have been found by a usual search, special circumstances are needed to justify a late amendment. CeraCon merely substitutes its own balancing for that of the judge rapporteur. The amendment is in any event excluded under Rule 263.2(a) RoP: CeraCon has not shown reasonable diligence, since the search string it relied on did not bring EP’480 into the search report and no explanation was given for the search provider’s omission. Any hardship can be dealt with through a stay or a conditional decision (Rule 118.2 RoP).

Key points for practice

• Practical point: a defendant seeking to add prior art must be able to explain why its initial search did not reveal it, a chance discovery is not enough.

Provisions applied

Rules of Procedure

Rules 25.1, 118.2, 263 and 333

Case law cited

TGI Sport Suomi Oy v AIM Sport Development AG, Court of Appeal, 11 April 2025 (UPC_CoA_169/2025)

Prepared by Dhenne Avocats from the official decision, consulted on 10 October 2026. The database is updated every week, on Friday. Only the official text is authoritative.