Dutch court bars MSD's subcutaneous Keytruda from eight European markets

A specialised Dutch patent court in The Hague has ruled that MSD's subcutaneous Keytruda infringes Halozyme's European patent EP 2,797,622 (EP622), and has ordered MSD BV to stop making, offering, importing or stocking the product in eight European markets¹. Halozyme announced the decision on 7 October 2026¹.

What the court decided

The order covers Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands¹. It is aimed at MSD BV, which Halozyme describes as Merck's central European marketing authorisation holder and its worldwide packaging and distribution hub¹. The injunction also bars MSD BV from helping affiliates infringe, including by letting them use its European marketing authorisation¹. The court dismissed MSD's argument that EP622 is invalid¹.

The patent belongs to Halozyme's MDASE family, which covers modified human hyaluronidases used to make large volumes of drug deliverable under the skin². The dispute centres on berahyaluronidase alfa, the enzyme in Keytruda SC that was developed by Alteogen and allows larger volumes to be absorbed through the skin². Halozyme says the MDASE patents stem from work on nearly 7,000 modifications to human hyaluronidases¹.

The intravenous form of Keytruda is outside both the patent and the order, so patients can still receive it¹. "We're very pleased the Dutch court recognized the validity and infringement of Halozyme's MDASE patent EP622," said Mark Snyder, Halozyme's chief legal officer¹.

This is the second European setback for the product. A German court granted Halozyme a preliminary injunction on 4 December 2025 that stopped the launch of Keytruda SC in Germany¹. Halozyme is also suing in the US federal district court in New Jersey, where it alleges that the subcutaneous product, sold in the US as Qlex, infringes 15 patents it began filing in 2011¹.

What it means for the market

The ruling matters because of what Keytruda SC is meant to do for MSD. In the second quarter of 2026 the subcutaneous form brought in $463 million of total Keytruda sales of $8.4 billion². It still trails the intravenous version, but it is expected to be a major factor in limiting the effect of biosimilar competition once the original formulation begins to lose patent protection from 2028². Blocking it across much of western Europe, on top of Germany, narrows the markets where MSD can move patients onto the new form before that date.

For hospitals and oncology services in the affected countries, the immediate effect is that the intravenous product remains the only Keytruda they can use¹. For other companies with subcutaneous biologics, Halozyme draws a line between MDASE and its separate Enhanze licensing programme. It says the MDASE patents are not part of Enhanze and that the Merck litigation will not affect any licensee's right to use Enhanze or the fees they pay¹. Halozyme says Enhanze is used in ten commercialised products across more than 100 markets, with licensees including Roche, Takeda, Pfizer, AbbVie, Eli Lilly and Bristol-Myers Squibb¹.

Caveats

The account of the judgment comes from Halozyme's own statement and one trade report built on it¹². Neither source sets out MSD's response or whether it will appeal, and Halozyme's release flags uncertainty over future decisions by the Dutch and German courts¹. The US case remains open, and its outcome is not yet known¹.