CeraCon v Sunstar Engineering (CoA, 2 September 2025)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By an order of 2 September 2025 (UPC_CoA_807/2025, APL_35616/2025), the standing judge of the Court of Appeal denied CeraCon’s request for discretionary review of the Mannheim Local Division’s order of 8 August 2025, which had refused it leave to add a new novelty attack to its counterclaim for revocation of Sunstar Engineering’s patent EP 4 108 413. The order confirms that a lack of reasonable diligence is enough to exclude an amendment under Rule 263, and that a deficient prior art search by a service provider does not excuse the party.

Question

Was the division manifestly wrong in the exercise of its discretion when it refused a new novelty attack based on Art. 54(3) EPC prior art that CeraCon’s search provider had failed to identify?

Decision

No. Leave is refused unless the applicant shows both that the amendment could not have been made earlier with reasonable diligence and that it will not unreasonably hinder the other party. Failure on diligence is sufficient (paragraphs 8 and 9). CeraCon admitted that its service provider had not found EP 3 868 480, later discovered by a patent attorney in an unrelated search, although the same search string returned it as the fifth hit (paragraph 11). Without a convincing explanation, the division did not exceed its discretion, and its order did not offend fairness, proportionality or procedural efficiency (paragraphs 12 and 13).

Key points for practice

• Practical point: a party seeking to add late prior art must explain precisely why the initial search did not reveal it, a failure by its search provider is attributed to the party.

Provisions applied

Rules of Procedure

Rules 220.3, 263 and 333

European Patent Convention

Art. 54(3)

Case law cited

No UPC decision is cited.

Related decisions

• CeraCon, 8 August 2025, order of the Mannheim Local Division panel subject to the review request.
• CeraCon, 6 June 2025, judge-rapporteur’s order initially refusing the amendment.

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.