Hologic v Siemens Healthineers (CFI, 21 May 2025)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By order of 21 May 2025, the Düsseldorf Local Division dismissed Siemens’ application for security for costs against Hologic, a US company suing it for infringement of EP 2 352 431 B1 (UPC_CFI_758/2024, with the counterclaim for revocation UPC_CFI_259/2025). The order confirms that a counterclaimant may seek security, but makes clear that difficulty of enforcement abroad must be proven, including the content of the foreign law.

Question

Does Hologic’s domicile in the United States (Massachusetts) make enforcement of a costs order unduly burdensome, so as to justify security of EUR 600,000 per proceeding?

Decision

The Division first held the application admissible: Rule 158.1 is not confined to the defendant in the main action, which disposed of Hologic’s objection to a counterclaimant applying. On the merits, the applicant need not show that enforcement is impossible, only that it would be unduly burdensome, but the burden is on the applicant, who must establish the foreign law and how it is applied. Siemens had offered only argument on Massachusetts law, with no evidence, so the application failed. The Division added that US courts routinely recognise and enforce foreign judgments. It left open the calculation of the amount, while doubting that two ceilings could be applied cumulatively.

Key points for practice

• Security for costs may be sought by a defendant who brings a counterclaim for revocation, including in respect of that counterclaim.
• Practical point: an application based on the absence of a recognition treaty must be supported by evidence of the foreign law and practice, bare assertions will not do.

Provisions applied

Agreement on a Unified Patent Court

Art. 69(4)

Rules of Procedure

Rule 158.1

Case law cited

Munich Local Division, 23 April 2024, UPC_CFI_514/2023, Court of Appeal, 17 September 2024, UPC_CoA_218/2024, Aarke v SodaStream Industries, 29 November 2024, Düsseldorf Local Division, 3 December 2024, UPC_CFI_140/2024

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.