Halozyme Secures Key Legal Victory Against Merck's Keytruda in Europe

Legal Victory for Halozyme Against Merck

On October 7, 2026, Halozyme Therapeutics, Inc. (Nasdaq: HALO) made headlines as the specialized Dutch patent court in The Hague ruled in favor of the company, blocking the manufacture and sale of Merck's Keytruda SC across numerous European markets. This landmark decision reinforces Halozyme's claims regarding the infringement of its MDASE patent, specifically EP 2,797,622 (EP622).

The ruling affects Merck's operations in key countries including Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland, and the Netherlands. The court's injunction prohibits Merck, through its central European Market Authorization Holder and packaging hub, MSD BV, from producing, marketing, or distributing Keytruda SC in these territories. Furthermore, it restricts MSD from aiding any affiliates that may contribute to this infringement.

Mark Snyder, Halozyme's Chief Legal Officer, expressed satisfaction with the court's ruling. He stated, "We're very pleased the Dutch court recognized the validity and infringement of Halozyme's MDASE patent EP622 and granted an injunction halting Merck's launch of Keytruda SC in multiple European markets." He highlighted that the MDASE technology has been meticulously developed for rapid and high-volume subcutaneous drug delivery, benefiting patients significantly.

Importantly, the court's decision allows patients to continue accessing Keytruda through its intravenous (IV) formulation, which remains unaffected by the injunction. This differentiation is stated to ensure that patients still receive necessary treatments, despite the restriction on the subcutaneous variant.

This Dutch ruling is a crucial component of Halozyme's global strategy of enforcing its MDASE patents against the production of Keytruda SC. The ongoing patent litigation against Merck extends beyond Europe, as Halozyme has previously taken legal action in Germany, where it secured a preliminary injunction halting the product launch in that region as well.

In the United States, the battle continues with Halozyme alleging that the subcutaneous formulation of Keytruda, marketed as QLEX, infringes on 15 patents related to MDASE technology, first filed in 2011. These patents are a result of extensive research on roughly 7,000 modifications of human hyaluronidases, showcasing Halozyme's commitment to innovation in the field.

The MDASE technology has cultivated advancements in the administration of therapeutic drugs, enabling rapid subcutaneous delivery, a feature that can significantly ease the treatment experience for patients.

Furthermore, it's important to note that the MDASE patents are distinct from Halozyme's ENHANZE® licensing program, meaning that the results of this legal enforcement will not affect existing licenses or fees associated with the ENHANZE® patents, thereby ensuring continuity for licensees in their operations.

About Halozyme

Halozyme is a pioneering biopharmaceutical company dedicated to enhancing patient experiences through innovative delivery systems. The company is recognized for its ENHANZE® drug delivery technology, which significantly simplifies administration processes for medications, ultimately improving patient compliance and comfort.

With over one million patients benefiting from its solutions across more than 100 markets, Halozyme has been instrumental in the commercialization of multiple therapeutic products developed in collaboration with leading pharmaceutical and biotechnology partners, such as Roche, Takeda, and AbbVie.

The company is also expanding its portfolio with the introduction of advanced technologies like Hypercon™ and Aerocon™. These innovations aim to redefine drug delivery standards by providing highly concentrated therapeutic options that can be administered in various settings, further broadening the scope of treatment options available to patients.

Headquartered in San Diego, California, Halozyme operates with a commitment to innovation at its core, continuously seeking enhancements in therapy delivery systems for better patient outcomes. For more information, interested parties are encouraged to visit their official website at www.halozyme.com and connect with them on LinkedIn.