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Permissible Amendment of the Action During Appeal and Obligation to Bear Costs in the Event of Equivalent Patent Infringement Despite Winning the Case

As the Düsseldorf Higher Regional Court has stated in a recent decision (decision of March 18, 2021 – 2 U 18/19) in accordance with its previous ruling practice, there are no concerns regarding the admissibility of the amendment of the application bylimiting the action to theinfringement of the patent-in-suit, which in the meantime has been maintained only with limited scope.

According to the Düsseldorf Higher Regional Court, this does not constitute an amendment of the action pursuant to § 263 German Code of Civil Procedure, but it is at most a limitation of the claim pursuant to § 264 no. 2 German Code of Civil Procedure, which is also admissible without further ado in the appeal proceedings. § 533 German Code of Civil Procedure does not apply in this respect. The plaintiff continues to base its action on the same facts of life and the same property right.

The Düsseldorf Higher Regional Court partially amended the first instance judgement and – while rejecting the further appeal – affirmed an infringement of the patent in suit under affirmation of the requirements of equivalence. However, after the plaintiff had for the first time in the appeal proceedings substantiated the requirement of equivalence, and thus in the result was also able to convince the appeal court, they were nevertheless obliged to bear the costs incurred by the appeal proceedings.


The admissibility of the amendment of the action in the appeal instance, following nullity proceedings or voluntary limitation that have been concluded in the meantime, is to be welcomed from the patent proprietor’s point of view.

In order to avoid a negative decision on costs, the amount of which may well be considerable depending on the amount in dispute, it should be noted, however, that in cases of possible equivalent patent infringement, substantiated submissions on the prerequisites of equivalence (if applicable also by submitting private expert opinions) should already be made in the first instance.

Our blog contributions shall provide an overview with regard to legal topics, legislation and case law and are supposed to provide some general information rather than constituting any specific advice. Please do not hesitate to contact Maiwald and in particular the authors of the particular contributions if have any questions on the addressed topics or on other legal issues.

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Dr. Christian Meyer



Certified IP Lawyer

UPC Representative