Biopharma company Halozyme Therapeutics has scored a major legal victory in Europe after a German court ordered pharma MNC Merck to stop distributing and offering the subcutaneous form of Keytruda (Keytruda SC) in Germany.

The Munich Regional Court’s 7th Civil Division found “imminent infringement” of one of Halozyme’s European MDASE patents — EP 2 797 622 — and granted a preliminary injunction that forces Merck to halt launch activities for Keytruda SC in the country.

While Merck can appeal, Halozyme said it expects the order to hold. Merck’s separate attempt to invalidate the patent, filed in August 2025, is still pending before the German Federal Patent Court.

Patients will continue to have access to the IV formulation of Keytruda, which is not covered by Halozyme’s patent or the injunction.

“We are very pleased the German court followed our arguments on the validity and infringement of one of our European MDASE patents and granted a preliminary injunction against Merck's imminent infringement of our patent," said Mark Snyder, chief legal officer of Halozyme.

"The MDASE technology was developed through years of rigorous research to enable rapid, high-volume subcutaneous drug delivery. We are committed to vigorously defending and enforcing our MDASE patents and are confident that we will prevail at trial.”

The German case is just one front in Halozyme’s global campaign to enforce its MDASE patent portfolio against Merck’s SC formulation of Keytruda.

In the US, Halozyme is suing Merck in federal court in New Jersey, alleging that the American version of Keytruda SC — marketed as QLEX — infringes 15 patents tied to Halozyme’s decade-long research program involving nearly 7,000 modifications to human hyaluronidases. These enzymes enable rapid subcutaneous administration of therapeutic drugs and represent a significant scientific advance for the field.

Halozyme emphasized that the MDASE patents at issue are separate from its ENHANZE platform and licensing program, meaning the Merck litigation has no impact on ENHANZE partnerships or revenue.