Halozyme Therapeutics HALO announced that a Dutch patent court has issued a ruling in its favor in a patent dispute with Merck MRK over Keytruda’s subcutaneous (SC) formulation.
The court found that Merck’s Keytruda SC infringes one of Halozyme’s MDASE patents, which covers technology used to deliver drugs through SC injection. The ruling orders Merck to stop manufacturing and selling Keytruda SC in Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands. It also prevents Merck from allowing its affiliates to continue selling the drug in these markets, including through the use of its European marketing authorization.
However, the court order does not affect the intravenous (IV) version of Keytruda. Patients will continue to have access to Keytruda IV because it is not covered by Halozyme’s patent or the court’s injunction.
This is not the first legal victory Halozyme has secured against Merck over Keytruda SC. In December 2025, a German court granted Halozyme a preliminary injunction that stopped Merck from distributing or offering Keytruda SC in Germany. HALO has also filed a separate patent infringement lawsuit against MRK in the United States, alleging that Keytruda SC, marketed as Keytruda Qlex, infringes 15 of its MDASE patents.
MRK Seeks to Fight the Ruling
Merck strongly disagrees with the Dutch court’s decision, according to Reuters. It considers Halozyme’s patent to be invalid globally and said its infringement allegation is without merit. Merck is evaluating its next steps.
The ruling is nevertheless an important setback for Merck as it seeks to expand the use of Keytruda. The SC version is intended to help extend Keytruda’s commercial opportunity as Merck approaches the loss of U.S. patent protection for the original formulation, with biosimilar competition potentially beginning in December 2028. Currently, the IV and SC versions together generate nearly half of Merck’s topline, making Keytruda an important part of the company’s strategy to preserve and extend the franchise.
For Halozyme, the widening restrictions on Keytruda SC could provide greater leverage in its broader patent dispute with Merck. While the latest ruling does not guarantee a financial benefit for HALO, additional court wins could strengthen its position in any future licensing or settlement discussions with Merck.
Year to date, the company’s shares have surged 65% compared with the industry’s 1% growth.
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The Dispute Does Not Affect HALO’s ENHANZE Business
Halozyme stated that the MDASE technology involved in the Merck dispute is separate from its ENHANZE technology and licensing program. This is particularly important for investors, given that ENHANZE is a major source of the company’s royalty revenues.
Halozyme has collaboration agreements with large pharma companies, like J&J JNJ and argenx ARGX, among others, which use its ENHANZE technology to develop SC formulations of their various approved drugs.
J&J uses the technology to administer the multiple myeloma therapy Darzalex (marketed as Darzalex Faspro/SC). On the other hand, argenx uses the same to deliver the generalized myasthenia gravis therapy Vyvgart, marketed as Vyvgart Hytrulo.
Per Halozyme, ENHANZE has been used in 10 commercialized products across more than 100 markets, while its growing number of partnerships provides further opportunities for milestone payments and royalties as new programs advance toward commercialization.
Halozyme Therapeutics, Inc. Price
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HALO’s Zacks Rank
Halozyme currently carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.
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