Merck faces European court injunction over Keytruda SC

Merck faces a commercial setback in Europe after Halozyme Therapeutics won a patent infringement injunction targeting the subcutaneous formulation of Keytruda, known as Keytruda SC. The specialized Dutch patent court in The Hague ruled that Merck infringed Halozyme's MDASE patent EP 2,797,622 and rejected Merck's arguments that the patent was invalid.

The court ordered Merck subsidiary MSD BV to stop manufacturing, offering, placing on the market, using, importing, or stocking Keytruda SC. The injunction applies to eight European markets: Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland, and the Netherlands. MSD is also barred from facilitating infringement by its affiliates, including through the use of its European Marketing Authorization.

Patients will continue to have access to the intravenous formulation of Keytruda, which is not covered by the patent or the court order. The Dutch decision follows an earlier preliminary injunction Halozyme secured in Germany on December 4, 2025, which halted the launch of Keytruda SC there.

Merck also faces ongoing legal challenges in the United States. Halozyme filed a patent infringement lawsuit against Merck in the U.S. federal district court in New Jersey, alleging that the subcutaneous formulation, marketed domestically as QLEX, infringes 15 patents filed since 2011.