Merck's Keytruda SC Launch Halted in Germany Amid Patent Dispute with Halozyme

Merck & Co.'s plans to introduce a subcutaneous version of its blockbuster cancer drug Keytruda in Germany have hit a significant roadblock. A German court has granted Halozyme Therapeutics a preliminary injunction, ordering Merck to cease launch activities for Keytruda SC in the country due to alleged patent infringement.

Legal Battle Unfolds

The court's decision, announced on December 4, 2025, stems from Halozyme's claim that Merck's subcutaneous formulation infringes on European Patent No. 2 797 622, part of Halozyme's Mdase family of intellectual property. This technology, according to Halozyme's chief legal officer Mark Snyder, "was developed through years of rigorous research to enable rapid, high-volume subcutaneous drug delivery."

Merck, known as Merck Sharp & Dohme in Germany, strongly disagrees with the court's ruling. A company spokesperson stated, "We consider Halozyme's patent to be invalid globally and their allegation of infringement to be without merit." Merck has expressed confidence in its legal position and intends to appeal the decision.

Implications for Keytruda SC in Europe

The injunction comes less than a month after Keytruda SC received approval from the European Commission. While the intravenous version of Keytruda remains available in Germany, the court order requires Merck to halt all launch activities for the subcutaneous formulation that fall within the scope of the injunction.

This legal setback in Germany is part of a broader global dispute between Merck and Halozyme. The subcutaneous drug developer has pledged "global enforcement" of its Mdase patents, including a lawsuit filed in the United States District Court in New Jersey in April 2025.

Future Outlook and Potential Resolution

Despite the ongoing litigation, Merck successfully launched Keytruda Qlex, the subcutaneous version, in the United States following FDA approval in September 2025. The company's ability to navigate similar challenges in other markets remains to be seen.

Earlier in 2025, Halozyme CEO Helen Torley expressed hope for a potential licensing agreement with Merck, suggesting a "reasonable" royalty rate as a possible resolution. However, with both companies firmly entrenched in their positions, the path forward remains uncertain. As the pharmaceutical industry watches closely, the outcome of this dispute could have far-reaching implications for the development and commercialization of subcutaneous drug formulations.