Balancing Disclosure Of Infringement And Exposure Of Trade Secrets - A UPC LD’s Three-step Approach

The Düsseldorf Local Division (LD) of the UPC has established a three-step framework for determining the scope of disclosure where confidential information is balanced against the applicant's need to assess patent infringement. 

In doing so it ordered the disclosure of the expert's detailed description of the inspected hydrogen production installations to the applicant, subject to specific redactions of confidential information and with access restricted to named individuals on the applicant's side (a confidentiality club).

Topsoe A/S v SYPOX GmbH and another (UPC_CFI_1696/2025, Düsseldorf LD, 21.08.2026) involved a patent for hydrogen production by steam methane reforming EP3802413. The headnotes provided by the court in this decision set out the three-step test:

"...the following assessment must be carried out to determine the scope of the disclosure of the detailed description to the applicant: 

1. The first step is to establish whether the information or evidence constitutes or contains trade secrets, personal data relating to third parties, or other confidential information. 
2. If this is the case, as a second step, this information must be redacted if it is irrelevant to the question of patent infringement or acts of use.
3. Where confidential information relates to the question of infringement and/or acts of use, a decision must be made on a case-by-case basis, as to whether it should be disclosed to the applicant, who would then be obliged to maintain confidentiality vis à-vis third parties, or whether the applicant’s access to such information should be restricted to a specific group of persons (third step)."

The Düsseldorf LD confirmed it had already set out this three-step test in Bekaert Binjiang Steel Cord Co. & Ltd. v. Siltronic AG and another (UPC_CFI_539/2024, 19.11.2025). In that case the outcome of the application of these principles was that price information and quantity information were held to be trade secrets and thus should be redacted alongside the confidential bank details of customers. It was considered that price and quantity information could be subject to disclosure if the patentee was successful in the main proceedings.

However, in Topsoe the Düsseldorf  LD went further, providing specific guidance on the interpretation of the second step with regard to the relevance of confidential information to the question of patent infringement (the second step, at b above):

• Information which the expert has actually relied on in his detailed description when examining patent infringement is generally considered relevant. It is for the respondent, who invokes the need for redaction, to demonstrate that this is not the case for certain information in exceptional circumstances. In doing so, the respondent may not rely on the argument that the patent infringement could have been adequately assessed on the basis of other information. 
• Where, on the other hand, the matter concerns information which the expert did not rely on when examining the question of infringement, it is for the applicant to demonstrate its relevance. If the expert has quoted extensively from documents when drawing up the detailed description, and the applicant nevertheless seeks disclosure of these documents as well, the applicant must also explain why the remaining content of these documents is significant in addition to the detailed description. 
• The relevance of certain information to patent infringement may also arise from the fact that, whilst such information is not directly necessary for determining whether the subject-matter falls within the scope of the patent claim, it is necessary for understanding the explanations as a whole.

Although this approach is the Düsseldorf LD's own and is not harmonised through a Court of Appeal decision, it provides a useful guide for patentees in framing their arguments for disclosure of information on alleged infringements and for defendants to argue for ring-fencing of information they regard as a trade secret and are keen to protect from exposure to competitors or any third parties.