On 14 July 2026 The District Court of The Hague published its judgment dismissing Halozyme’s application for a preliminary injunction (PI) to prevent MSD from marketing Keytruda SC™ (pembrolizumab and berahyaluronidase alfa) in Denmark and Sweden pending the outcome of substantive proceedings.
In the substantive proceedings, MSD is seeking a declaration of non-infringement and the revocation of the Dutch part of Halozyme’s European patent EP 2792622 (EP622), which expires on 27 December 2032. EP622 relates to recombinant human modified PH20 hyaluronidase (rHUPH20) polypeptides. Halozyme has cross-claimed for infringement of EP622, seeking cross-border injunctions covering all countries where the patent is in force, except Germany (where a PI is already in place). The oral hearing in the substantive proceeding is scheduled for 31 July 2026.
The preliminary injunction application arose from a statement that MSD made in its reply to Halozyme’s cross-claim. In that statement, MSD claimed that Halozyme’s suggestion that MSD intended to bring Keytruda SC™ to market “as quickly as possible” in the relevant EU countries was “unfounded and incorrect”. Halozyme argued that this was a “binding undertaking” or at least created a legitimate expectation that MSD would not launch Keytruda SC™ in those countries before the conclusion of the main proceedings. Halozyme argued this undertaking or expectation was breached by MSD’s subsequent conduct in listing Keytruda SC™ in the Swedish and Danish national pricing databases.
In deciding the PI application in favour of MSD, the Court found that MSD’s statement in its pleadings did not create an enforceable undertaking and Halozyme could not reasonably have interpreted the statement as a declaration of MSD’s intent without further verification.
MSD and Halozyme are also in dispute elsewhere over patents to Halozyme’s MDASE™ subcutaneous delivery technology. In December 2025, the Munich Regional Court granted a PI to Halozyme, preventing MSD from distributing and offering for sale in Germany Keytruda SC™, based on a finding of the Court that there was imminent infringement of EP622. In April 2024, Halozyme sued MSD in the US, alleging that MSD’s subcutaneous Keytruda® (Keytruda Qlex®) infringes 15 patents. MSD has successfully invalidated claims of 4 of Halozyme’s US patents before the Patent Trial and Appeal Board (PTAB) and has a further 13 petitions pending before PTAB.
While there are no reports of biosimilar subcutaneous pembrolizumab development to date, there are multiple pembrolizumab biosimilars approved or in development. Pembrolizumab biosimilars have reportedly been launched in Paraguay (by Bioeticos in August 2025) and approved in Vietnam (by Biocad in November 2025) and Jordan (by Sana Pharma in February 2026). Pembrolizumab biosimilars are also in clinical trials including by Formycon, Samsung Bioepis, Amgen, mAbxience, Sandoz, Celltrion, Bio-Thera, Shanghai Henlius, BioNTech, Qilu Pharmaceutical and Enzene.