Merck Rises as Keytruda Space Research Seeks New Orbital Home

A Dutch patent court has ruled in favor of Halozyme Therapeutics, finding that Merck's subcutaneous formulation of Keytruda infringes one of Halozyme's MDASE patents covering technology used to deliver drugs through subcutaneous injection. The ruling orders Merck to stop manufacturing and selling Keytruda SC in Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands, and bars Merck from letting its affiliates continue selling the drug in those markets, including through its European marketing authorization. The order does not affect the intravenous version of Keytruda, which remains available to patients because it is not covered by Halozyme's patent or the injunction. It marks the second legal victory for Halozyme over Keytruda SC, following a December 2025 German preliminary injunction that stopped Merck from distributing or offering the drug in Germany, and Halozyme has also filed a separate U.S. patent infringement lawsuit alleging that Keytruda SC, marketed as Keytruda Qlex, infringes 15 of its MDASE patents. Merck said it strongly disagrees with the Dutch decision, considers Halozyme's patent invalid globally and the infringement allegation without merit, and is evaluating its next steps. The ruling is a setback for Merck as it seeks to expand Keytruda's use ahead of the loss of U.S. patent protection for the original formulation, with biosimilar competition potentially beginning in December 2028; the IV and SC versions together generate nearly half of Merck's topline. Halozyme said the MDASE technology in the Merck dispute is separate from its ENHANZE technology and licensing program, which is a major source of royalty revenue and has been used in 10 commercialized products across more than 100 markets, including Johnson & Johnson's Darzalex and argenx's Vyvgart. Halozyme shares have surged 65% year to date compared with the industry's 1% growth.