Dutch patent injunction extends across eight European countries

The District Court of The Hague granted cross-border relief to Halozyme Inc. after rejecting claims from a Dutch subsidiary within the Merck Sharp & Dohme Group (MSD) that Halozyme’s patent was not valid. The relief extends to Belgium, Denmark, France, Ireland, Italy, Sweden and Switzerland, as well as the Netherlands.

MSD markets the medicine Keytruda, one of the world's biggest-selling cancer drugs. The case before the Dutch court revolved around a new form of Keytruda (Keytruda SC), which enables the product to be administered via injection under a patient’s skin.

MSD has obtained authorisation to market Keytruda SC in the EU. It has subsidiaries across some member states for the purposes of exercising its marketing authorisation, while its US manufacturing licence lists a Dutch subsidiary as among the entities authorised to manufacture Keytruda SC. That company told the Dutch court that it intended to launch Keytruda SC in the Netherlands in 2026. The product has already been launched in Denmark and Sweden.

Halozyme has taken issue with MSD’s plans, arguing that MSD’s formulation for Keytruda SC infringes patent rights it owns. Halozyme has taken legal action before the courts in various jurisdictions – including in Germany, France and the UK, where it asserts European patent rights.

MSD initiated the Dutch proceedings, seeking a declaration of non-infringement (DNI) from the court. It further invited the court to find Halozyme’s European patent invalid. However, the court, which specialises in patent litigation, upheld counterclaims raised by Halozyme, rejected MSD’s DNI application, held Halozyme’s patent to be valid, and determined that there was sufficient evidence of an imminent infringement of the patent by MSD in eight European countries.

The Hague court rejected MSD’s arguments that it should stop short of issuing an interim order with cross-border effect because national courts in other European jurisdictions have yet to resolve the patent dispute over Keytruda SC.

The Dutch court cited landmark case law established by the Court of Justice of the EU (CJEU) in the case of BSH v Electrolux, which sets out when courts of member states have jurisdiction to determine claims of infringement of European patents in every country in which those patents apply. It considered the thresholds for acting in this way were met in this case.

The Hague court determined that there was no reasonable, non-negligible prospect that courts in the other seven countries would invalidate the patent. A preliminary opinion issued by a court in Germany, in which the court granted Halozyme a preliminary injunction and rejected MSD’s invalidity defence, was considered by the Dutch court in this regard.

It also expressly relied on Unified Patent Court and European Patent Office case law when interpreting the patent, with it being persuaded that the high degree of harmonisation of European patent law would mean Keytruda SC would be held as infringing in the other countries that Halozyme’s European patent has been validated.

The fact MSD’s Dutch subsidiary operates as a manufacturing and distribution hub and holds marketing authorisation rights also supported the finding that it was involved in infringing activities extending beyond the Netherlands, justifying cross-border injunctive relief, the court considered.

The application of the interim order to Belgium, Denmark, France, Ireland, Italy, Sweden and Switzerland will cease to have effect if the competent national court in those jurisdictions declares Halozyme’s European patent as invalid, though the Dutch order would be reinstated in effect in those countries if the patent is later upheld on appeal. Revocation actions remain pending in, among others, Denmark, Sweden and Switzerland.

Marthe Riewald, a life sciences patent litigation expert at Pinsent Masons, said: “The judgment is notable for its application of the CJEU’s decision in BSH v Electrolux. The Hague court expressly recognised that earlier Dutch Supreme Court case law must be revisited in light of that ruling, illustrating the far-reaching impact of BSH on cross-border patent enforcement strategies in Europe.”

Carly van der Beek, an expert in medicines regulation at Pinsent Masons, said: “For life sciences businesses, the decision highlights how regulatory and operational structures may influence jurisdictional risk. The court attached significance not only to manufacturing and distribution activities in the Netherlands, but also to the holding and exercise of marketing authorisation rights when assessing whether cross-border relief was justified.”