Dutch Court Grants Keytruda SC Injunction in Eight European Markets

A Dutch court granted Halozyme a Keytruda SC injunction against the subcutaneous form of pembrolizumab. The District Court of The Hague ruled that the product falls inside European patent EP 2 797 622. The judgment, issued on 7 October 2026 in case C/09/695432 / HA ZA 25-1075, orders MSD to halt manufacturing, offering, marketing and use of the product in Belgium, Denmark, France, Ireland, Italy, the Netherlands, Sweden and Switzerland. It also bars imports and stockpiling for those purposes. MSD must comply within seven days of service.

MSD filed first and asked the court to declare non-infringement and revoke the Dutch portion of the patent. Halozyme filed a counterclaim that sought a finding of infringement, an injunction and a ban on facilitation by group companies, in particular through the central European marketing authorisation. Halozyme succeeded on the substantive points, and the court directed MSD to pay the full costs of the case.

The patent at the centre of the case

EP 2 797 622 is titled “PH20 polypeptide variants, formulations and uses thereof”. It covers modified PH20 polypeptides that keep more enzymatic activity in the presence of a phenolic preservative than the unmodified enzyme. Halozyme’s Enhanze and MDASE platforms both rely on recombinant human PH20 hyaluronidase (rHuPH20). The enzyme temporarily increases tissue permeability and allows medicines that once required intravenous delivery to move to subcutaneous injection.

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The patent claims priority from 30 December 2011 and 1 November 2012, was granted on 12 October 2016 and runs until 27 December 2032. No opposition was filed at the European Patent Office. The patent remains in force in the Netherlands, Belgium, Switzerland, Germany, Denmark, Spain, France, the United Kingdom, Ireland, Italy and Sweden.

Claim 1 is the sole independent claim among the 19 claims. It requires a modified PH20 polypeptide with at least one amino acid replacement at one of 66 listed positions relative to SEQ ID NO:3, together with increased stability in the presence of a phenolic preservative shown by higher hyaluronidase activity than the unmodified polypeptide under the same conditions.

An injunction that crosses borders, with a condition attached

Halozyme sought relief in eight countries. MSD argued that there was no concrete threat of launch outside the Netherlands, that it had performed no reserved acts abroad and that the case should be stayed pending invalidity proceedings elsewhere in Europe. On the threat, the court found the evidence clear: MSD told the court in September 2025 that it intended to bring Keytruda SC to the Dutch market during 2026, and its Swedish and Danish affiliates placed the product on the market while the case was pending. As holder of the central marketing authorisation and the entity responsible for batch release, MSD was held to supply those affiliates and therefore to offer and market the product in the countries concerned.

The court refused to stay the proceedings. Applying the Court of Justice’s BSH/Electrolux ruling, it found no reasonable and non-negligible chance that another competent European court would invalidate the patent. It pointed to its own validity conclusion, the German Federal Patent Court’s preliminary view that the patent is valid and the Munich Regional Court’s rejection of the invalidity arguments in the German preliminary injunction proceedings. MSD did not identify different prior art or evidence being used elsewhere.

Because the judgment reaches patents outside the Netherlands, the court attached a condition to the cross-border parts of the relief. The declaration and the injunctions lose effect if the relevant national part of EP 2 797 622 is invalidated by the competent national court, and the injunction revives if the patent is later upheld on appeal. The court noted that this approach departs from the Dutch Supreme Court’s decision in Roche/Primus II, which predates BSH/Electrolux and which the court regarded as overtaken on this point and impractical because it would produce many stayed cases.

Keytruda SC injunction: what the court ordered

Source: Rechtbank Den Haag, judgment of 7 October 2026, case C/09/695432 / HA ZA 25-1075. The ruling is announced in the Halozyme press release of 7 October 2026.

The truthfulness finding, and what it did not change

One exchange drew a formal rebuke. In its defence of 8 April 2026, MSD described Halozyme’s suggestion that the MSD group intended to bring subcutaneous pembrolizumab to market in the other EU countries where the patent is in force as “unfounded and incorrect”. Less than a month later, MSD’s Swedish and Danish companies placed Keytruda SC on sale in those two countries. The court held that MSD had breached the duty to state the facts fully and truthfully under Article 21 of the Dutch Code of Civil Procedure. It attached no further consequence, because Halozyme had already obtained almost everything it sought and MSD had been ordered to pay costs at the highest indicative rate. The same treatment applied to MSD’s overrun of the word limit for written pleadings and its late productions.

The court also narrowed two of Halozyme’s requests. It refused the order as far as it concerned unlisted third parties, because Halozyme had not argued that anyone beyond the MSD group was involved, and it refused the facilitation ban for the Netherlands, because no other MSD company was shown to be involved in infringement there.

What the ruling means for access

The immediate effect is that patients in the eight countries retain access to intravenous Keytruda, which the patent does not cover, while the subcutaneous version remains off the market. For MSD the decision interrupts a launch that was central to extending the commercial life of its largest product. For Halozyme it is the second European court to side with it against MSD, after the German preliminary injunction granted in December 2025, and it clears the way for a damages claim: the court accepted that Halozyme has an interest in the declaration partly because it says it lost market share for Opdivo SC, the nivolumab product that Bristol Myers Squibb markets in Europe under licence from Halozyme, and because it may sue for compensation later.

The condition attached to the cross-border relief means the picture can change country by country. Invalidity proceedings are already under way in Denmark, Sweden and Switzerland, alongside the German case at the Federal Patent Court, an action in France and proceedings in the United Kingdom. Cases concerning patents from the same family are running in the United States, Israel and Canada. Any national court that invalidates its part of EP 2 797 622 will, from that moment, remove the injunction for that territory.