Attorney at Law & Partner
Attorney at Law & Partner
Attorney at Law
On 7 October 2026, the District Court of The Hague (the “Court”) handed down its decision in proceedings between Merck Sharp & Dohme B.V. (“MSD”) and Halozyme Inc. (“Halozyme”) concerning Halozyme’s EP 2 797 622 B1 (“EP 622”) for modified PH20 polypeptide variants. The Court rejected MSD’s invalidity and non-infringement arguments. It held that MSD’s subcutaneous formulation of the API pembrolizumab, marketed as Keytruda (“Keytruda SC”), containing the hyaluronidase enzyme berahyaluronidase alfa (“ALT-B4”), infringes EP 622. The Court granted Halozyme cross-border injunctions for the Dutch, Belgian, Danish, French, Irish, Italian, Swedish and Swiss parts of EP 622, subject to the condition that the respective foreign part of EP 622 remains valid.
EP 622 claims modified PH20 polypeptides meeting specified sequence and functional requirements, including increased stability in the presence of phenolic preservatives. PH20 hyaluronidase temporarily increases tissue permeability and enables medicines that were previously administered intravenously to be administered subcutaneously. MSD developed Keytruda SC, a subcutaneous formulation containing pembrolizumab as active substance and ALT-B4.
MSD requested a declaration of non-infringement and revocation of the Dutch part of EP 622. Halozyme counterclaimed for declarations of infringement and injunctions regarding the Dutch and, cross-border, seven foreign parts of EP 622, including an injunction for unlawfully facilitating infringement by its group companies.
The Court construed claim 1 as a product claim with functional features. Therefore, the relevant phenol-stability test had to be performed on the modified PH20 polypeptide as such, not on the final Keytruda SC formulation. It was irrelevant that Keytruda SC itself does not contain a phenolic preservative or makes use of ALT-B4’s phenol stability.
MSD’s invalidity attacks failed. The Court held EP 622 sufficiently disclosed, novel, inventive and not to contain added matter.
The Court found that ALT-B4 satisfies all features of claim 1 of EP 622, including the claimed amino-acid substitutions and the functional phenol-stability feature. Halozyme’s evidence sufficiently showed increased phenol stability; MSD’s counter-study tested co-formulations rather than ALT-B4 as such.
The Court rejected MSD’s argument that Keytruda SC falls outside the scope of EP 622 because it does not contain a phenolic preservative and therefore does not make use of ALT-B4’s increased phenol stability.
In Germany, validity proceedings are pending before the Bundespatentgericht, which has issued a preliminary opinion stating that the German part of EP 622 is valid. The Landgericht München has granted a PI against infringement of the German part of EP 622; MSD has appealed that decision. Parallel invalidity proceedings are pending in France, Denmark, Sweden and Switzerland. Proceedings concerning both invalidity and infringement of the UK part of EP 622 are pending before the High Court. Related proceedings concerning patents from the same patent family are also pending in the United States, Israel and Canada.
Referring to the CJEU decision in BSH Hausgeräte/Electrolux, the Court held that pending foreign invalidity proceedings do not automatically require a stay. The relevant question is whether there is a reasonable and non-negligible chance that foreign (parts of European) patent(s) will be invalidated. The Court saw no such chance: it had rejected MSD’s invalidity attacks against the Dutch part, the Bundespatentgericht had issued a positive preliminary validity opinion on the German part, and the Landgericht München had rejected MSD’s invalidity arguments in PI proceedings.
The Court also considered that MSD did not rely on any materially different invalidity arguments, prior art or evidence in said foreign proceedings. The Court ruled that the respective cross-border injunction lapses if the relevant national part is held invalid by the competent national court and revives if that finding is overturned on appeal.
The Court also considered whether MSD acted unlawfully by facilitating infringement through its central European marketing authorization (“MA”). It held that merely holding an MA is not an infringement, but involvement in infringement may amount to an unlawful act under Dutch law. The Court prohibited MSD from unlawfully facilitating infringement committed by MSD group companies, by making its MA for Keytruda SC available to them.
The decision confirms that a modified enzyme may infringe a product claim with functional features even if the marketed formulation does not itself contain the excipient or condition by which the claimed functional property is tested. The Court granted cross-border injunctions without staying the case despite parallel foreign invalidity proceedings, because it saw no reasonable chance of invalidation. Moreover, the decision underlines that a MA holder may act unlawfully if it intentionally facilitates infringing launches by affiliated companies.
Attorney at Law & Partner
Attorney at Law & Partner
Attorney at Law