Halozyme Strengthens Subcutaneous Leadership Through Major European Patent Victory and Expanded argenx Partnership

Halozyme Therapeutics is solidifying its footprint in the subcutaneous drug delivery sector through a pair of high-impact milestones. In a span of just 24 hours, the company secured a major legal victory restricting Merck’s Keytruda SC across multiple European markets and broadened its strategic licensing collaboration with argenx.

Dutch Court Rules in Favor of Halozyme in Keytruda SC Patent Battle

On October 7, 2026, a specialized Dutch patent court in The Hague ruled that Merck infringed upon Halozyme’s MDASE patent (EP 2,797,622). The court ordered Merck’s European packaging and distribution hub, MSD BV, to halt the manufacturing, distribution, marketing, and importing of Keytruda SC across key European jurisdictions, including:

Belgium
Denmark
France
Ireland
Italy
Sweden
Switzerland
The Netherlands

The court explicitly dismissed Merck’s counterarguments challenging the patent’s validity. Halozyme clarified that the injunction targets only the subcutaneous formulation and does not impact patients’ access to the intravenous (IV) version of Keytruda. This decision builds on prior enforcement momentum, following a preliminary injunction granted in Germany in December 2025 and ongoing litigation in the United States. Halozyme also emphasized that the MDASE patents under litigation are separate from its core ENHANZE licensing portfolio, ensuring licensee operations remain unaffected.

Broadening the argenx Collaboration

In tandem with its legal enforcement efforts, Halozyme announced an expansion of its global partnership with argenx on October 6, 2026. Under the revised agreement, argenx gains exclusive access to Halozyme’s ENHANZE technology for two additional targets, growing the total number of exclusive targets under the collaboration from six to eight.

Building on the success of VYVGART Hytrulo—which provides alternative subcutaneous administration options for patients suffering from chronic inflammatory demyelinating polyneuropathy and myasthenia gravis—the expanded scope positions Halozyme to earn further milestone payments and royalty revenues on future commercial net sales.

Driving Industry Shift Toward Subcutaneous Delivery

Powered by its proprietary recombinant human hyaluronidase enzyme, rHuPH20, Halozyme’s ENHANZE technology has already facilitated subcutaneous delivery across 10 commercialized products in over 100 markets, touching more than one million patients. Together, these recent developments underscore a dual-pronged corporate strategy: fiercely protecting proprietary intellectual property while simultaneously expanding collaborative pipelines to transform patient treatment experiences.