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UPC Court of Appeal issues important decision on language of proceedings

Posted on 29 April 2024

The Court of Appeal has set out the factors to be considered when deciding on a request to change the language of UPC proceedings. In this significant decision in the case of 10x Genomics v Curio Bioscience, the Court of Appeal agreed with Curio Bioscience that the language of the proceedings before the Düsseldorf Local Division should be changed from German to English.

In reaching its conclusion, the Court set out the relevant (as well as less relevant or irrelevant) factors when making such a determination. Given the approach taken by the Court of Appeal, it seems likely that there will be a further shift towards proceedings being conducted in English. As at 29 March 2024, the latest statistics from the UPC were already showing that English made up 45% of the language of first instance proceedings, with German at 47%.


10x Genomics has brought infringement proceedings against Curio Bioscience before the Düsseldorf Local Division, and sought provisional measures, relating to English language patent EP 2 697 391. The proceedings were issued in German. Under Article 49(5) of the UPC Agreement, the President of the Court of First Instance may, on grounds of fairness and taking into account all relevant circumstances, including the parties' positions, in particular the Defendant's position, decide that the language of the patent should instead be used for the proceedings.

Curio Bioscience applied for a change of language of the proceedings from German to English but this was rejected by the President of the Court of First Instance. The application for provisional measures was accordingly heard in German, and Curio Bioscience appealed to the Court of Appeal in relation to the decision on language.


Whilst the President of the Court of First Instance had a margin of discretion when assessing fairness, the Court of Appeal overturned the decision not to change the language of the proceedings from German to English.

In doing so, it has set out the relevant circumstances that should be taken into account. In particular, it noted that Art. 49(5) UPC Agreement provides that the position of the Defendant should in particular be taken into account and, where the balance of interests is equal, is decisive.

Factors to be considered are as follows:

Relevant circumstances relating to the specific case

  • The language mostly used in the field of technology.
  • The language the evidence (including the prior art) is primarily written in.
  • How a change of language will affect the course of the proceedings and may lead to a delay, especially in relation to the urgency of the case (whilst delay is generally disadvantageous to a Claimant, it can be extra burdensome for a Defendant to defend itself, particularly in summary proceedings, in a different language).

Relevant circumstances relating to the parties

  • The nationality or domicile of the parties.
  • The size of the parties relative to each other (e.g. multinational vs small company with limited resources).
  • Where the balance of interests is equal, the Defendant's position is decisive. This is because a Claimant bringing proceedings in a Division with several designated languages can choose the language of the proceedings, as well as choosing where to bring its action and when (and indeed how long to spend on preparing its case). Further, a patentee Claimant will have chosen the language of the patent when filing the application, and should be aware that this will dictate the language of EPO proceedings (with the same point applying where a patent has been acquired). The language of the patent is also of importance in issues of claim construction.

Circumstances that are generally irrelevant

  • Whether a representative has specific language skills. If the language of the proceedings is not the language of a party, this is not compensated by the fact that its representative is proficient in that language.
  • Nationality of judges hearing a case.  

Applying these factors in this case, the assessment came out as follows:

  • Factors of considerable weight: Both companies are US companies, the language of the underlying technology field is English, the infringement evidence is almost exclusively in English, and the majority of the defence evidence is also in English. 
  • Non-decisive factors: that Curio Bioscience is (as asserted) an SME, though the Court noted it was evident it was a smaller company and therefore the disadvantage of the language being different was a heavier burden.
  • Facts of less or no relevance: the fact that 20% of EU citizens speak German natively and 10% as a foreign language; the fact that Curio Bioscience as a US based company is familiar with the German language; the language qualifications of the parties representatives and of the judges (all of whom also speak English).

Finally, whilst a change of language would entail additional work which could delay the proceedings (given the application for provisional measure had already been heard), it could be provided (and indeed an order was subsequently made to this effect) that the Court could make its order and deliver its decision in German, alongside a certified translation into English.

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