Sunstar Engineering v CeraCon (UPC_CFI_745/2024)
Decision date:
08 August 2025
Osborne Clarke summary
- In this case, the Mannheim LD refused CeraCon leave to amend its revocation counterclaim under Rule 263 RoP to introduce new prior art. The application was made two months after its counterclaim, coinciding with the deadline for the defence to counterclaim. Thus judge-rapporteur held that it was too late. CeraCon's claim that the new prior art was a very strong novelty attack was irrelevant. As the judge-rapporteur refused CeraCon's request, it submitted a request for a review of the judge-rapporteur's decision by the panel.
- The Mannheim LD upheld the judge-rapporteur's decision. Where a prior art document "can be easily found applying an [sic] usual search method", there must be special circumstances to justify leave to amend. None were present here, and the panel was unconvinced that CeraCon had acted with reasonable diligence. Indeed, CeraCon admitted that its search string identified the prior art and it must have been overlooked by the search providers. The panel decided that admitting the new prior art at this stage would "unreasonably hinder" the patentee's defence to revocation and would delay the trial.
- The panel was not swayed by the argument that the new prior art was highly relevant, being largely identical to the patent in suit. CeraCon argued that it was clear beyond doubt that the patent was invalid, and thus it was in the interests of the public and procedural economy to admit it, rather than require separate proceedings. The panel rejected these arguments, noting that any "unacceptable hardship" could be avoided by suspending the infringement proceedings or rendering a conditional decision, pending a separate revocation action.
Issue
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