On 7 October 2026 the specialised patent court in The Hague found that Merck infringes one of Halozyme's MDASE European patents, EP 2,797,622 (EP622), and rejected Merck's argument that the patent is invalid. The court ordered MSD BV, Merck's central European marketing authorisation holder and worldwide packaging and distribution hub, to refrain from manufacturing, offering, placing on the market and using, or importing or stocking for those purposes, subcutaneous Keytruda (Keytruda SC) in Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands. The injunction also bars MSD BV from facilitating infringement by its affiliates, including by allowing use of its European marketing authorisation. According to reports, Merck said it strongly disagreed with the ruling and would seek to overturn it.
The ruling concerns only the subcutaneous formulation; Halozyme says the intravenous version of Keytruda is not covered by the patent or the injunction and remains available to patients.
Keytruda is one of the world's best-selling cancer drugs, which is why the commercial impact of the case is drawing attention. Nor is this the first round between the parties: on 4 December 2025 the Munich Regional Court granted a preliminary injunction against the launch of Keytruda SC in Germany based on the same EP622 patent, and Halozyme has also sued Merck in the US federal district court in New Jersey, alleging that the subcutaneous formulation marketed in the United States as QLEX infringes 15 of its patents.
J&C notes that for companies pursuing reformulation, new routes of administration or life-cycle management, third-party patents on excipients, delivery technology and formulation processes can block a launch just as much as the patents on the original drug; before launching a new formulation, they should run freedom-to-operate analyses market by market, assess the risk of injunctions and of the marketing authorisation being drawn in, and prepare invalidity defences, licence negotiations or alternatives in advance.
Source: ir.halozyme.com | gxpnews.net | www.prnewswire.com
