Halozyme Wins Injunction Stopping Manufacture and Sale of Merck's Keytruda SC in Multiple European Markets

SAN DIEGO, Oct. 7, 2026 /PRNewswire/ -- Halozyme Therapeutics, Inc. (Nasdaq: HALO) ("Halozyme" or the "Company") announced today that the specialized Dutch patent court of the Hague has found Merck to be infringing one of its MDASE patents, EP 2,797,622 (EP622) and ordered Merck's central European Market Authorization Holder and worldwide packaging and distribution hub MSD BV to refrain from manufacturing, having manufactured, offering, placing on the market and using, or importing or stocking for these purposes, Keytruda SC in Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands. The injunction also forbids MSD to facilitate infringement by its affiliates, including by allowing the use of its European Marketing Authorization. The court also rejected Merck's arguments that EP622 patent is invalid.

"We're very pleased the Dutch court recognized the validity and infringement of Halozyme's MDASE patent EP622 and granted an injunction halting Merck's launch of Keytruda SC in multiple European markets. The MDASE technology was developed through years of rigorous research to enable rapid, high-volume subcutaneous drug delivery," said Mark Snyder, Chief Legal Officer of Halozyme.

Importantly, patients who want to use Keytruda will still have access to the IV version of Keytruda, which is not covered by Halozyme's patent or the court's injunction order.

The Dutch proceedings are part of Halozyme's global enforcement of its MDASE™ patents against infringement by Merck's Keytruda SC. Halozyme previously sued Merck in Germany and was granted a preliminary injunction on December 4, 2025, stopping Merck's launch of Keytruda SC in Germany.

Halozyme has also sued Merck for patent infringement in U.S. federal district court in New Jersey. In that case, Halozyme alleges the subcutaneous formulation of Keytruda, which is being marketed in the U.S. as QLEX, infringes 15 patents that Halozyme filed beginning in 2011 to protect its MDASE™ technology. The patents at issue arise from Halozyme's extensive research into nearly 7,000 modifications to human hyaluronidases. Among their uses, these hyaluronidases pioneered by Halozyme provide a mechanism for the rapid SC administration of therapeutic drugs. Halozyme's comprehensive studies and innovations were a significant advancement to the field of human-derived hyaluronidases.

The MDASE™ patents are not included in Halozyme's ENHANZE^® licensing program and are distinct from its ENHANZE^® patents. Therefore, the outcome of the global enforcement of its MDASE™ patents against Merck will not impact the ability of any licensee to use ENHANZE^®, or the license fees for use of ENHANZE^® patents.

About Halozyme

Halozyme is a biopharmaceutical company advancing disruptive solutions to improve patient experiences and outcomes for emerging and established therapies. As the innovators of ENHANZE^® drug delivery technology with the proprietary enzyme rHuPH20, Halozyme's commercially-validated solution facilitates the subcutaneous delivery of injected drugs and fluids, reducing treatment burden and improving convenience. ENHANZE^® has touched more than one million patient lives through ten commercialized products across over 100 global markets and is licensed to leading pharmaceutical and biotechnology companies including Roche, Takeda, Pfizer, Janssen, AbbVie, Eli Lilly, Bristol-Myers Squibb, argenx, ViiV Healthcare, Chugai Pharmaceutical, Acumen Pharmaceuticals, Merus N.V., GSK, and Incyte.

Halozyme expanded its drug delivery technology portfolio to develop partner products using Hypercon™ and Surf Bio's hyperconcentration technology, recently renamed as Aerocon™. Hypercon™ is an innovative microparticle technology expected to set a new standard in hyperconcentration of drugs and biologics by reducing injection volume for the same dosage and enabling administration in at‑home and healthcare‑provider settings. Aerocon's polymer‑based hyperconcentration technology further broadens the range of biologics that can be delivered subcutaneously, meaningfully expanding the scope of opportunities across therapeutic modalities. Together, Hypercon™ and Aerocon™ complement ENHANZE^® by enabling creation and delivery of highly concentrated biologics. The Hypercon™ technology has been licensed to leading biopharmaceutical partners, including Janssen, Eli Lilly, argenx, Vertex Pharmaceuticals and Oruka Therapeutics.

Halozyme also develops, manufactures and commercializes drug-device combination products using advanced auto-injector technologies designed to improve convenience, reliability and tolerability, enhancing patient comfort and adherence. The Company has two proprietary commercial products, Hylenex^® and XYOSTED^®, partnered commercial products and ongoing development programs with Teva Pharmaceuticals and McDermott Laboratories Limited, an affiliate of Viatris Inc.

Halozyme is headquartered in San Diego, CA, with offices in Ewing, NJ; Minnetonka, MN; and Boston, MA. Minnetonka is also the site of its operations facility.

For more information, visit www.halozyme.com and connect with us on LinkedIn.

Safe Harbor Statement

In addition to historical information, the statements set forth above include forward-looking statements including, without limitation, statements concerning the possible activity, benefits and attributes of Halozyme's ENHANZE^® and MDASE™ drug delivery technologies, the possible method of action of these technologies, their potential application to aid in the dispersion and absorption of other injected therapeutic drugs, and statements concerning certain other potential benefits of these technologies including facilitating more rapid delivery of high-volume injectable medications through subcutaneous delivery and potentially easing the treatment burden for patients and improving patient outcomes. These forward-looking statements include statements with respect to the decision of a Dutch court to order MSD BV to refrain from manufacturing, having manufactured, offering, placing on the market and using, or importing or stocking for these purposes, Keytruda SC in Belgium, Denmark, France, Ireland, Italy, Sweden, Switzerland and the Netherlands, and forbidding MSD BV to facilitate infringement by its affiliates, including by allowing the use of its European Marketing Authorization, the decision of a German court to issue a preliminary injunction ordering Merck to refrain from distributing and offering Keytruda SC in Germany, and statements with respect to the strength and validity of Halozyme's intellectual property. These forward-looking statements also include statements with respect to Halozyme's patent infringement suit against Merck Sharp & Dohme LLC, to enforce Halozyme's patent rights, including Halozyme's allegation that Merck's SC Keytruda infringes multiple Halozyme patents and Halozyme's belief that the outcome of the lawsuit will not impact its ENHANZE^® licensing program or the revenues Halozyme receives from ENHANZE^® licensees. These forward-looking statements involve risks and uncertainties beyond Halozyme's control that could cause actual results to differ materially from those in the forward-looking statements. The forward-looking statements are typically, but not always, identified through use of the words "expect," "believe," "enable," "may," "will," "could," "intends," "estimate," "anticipate," "plan," "predict," "probable," "potential," "possible," "should," "continue," and other words of similar meaning. Actual results could differ materially from the expectations contained in forward-looking statements as a result of several factors and Halozyme can offer no assurance with respect to such forward-looking statements and cautions the reader not to place undue reliance on these forward-looking statements. In particular, there can be no assurance as to developments related to the litigation referred to in this press release, the outcome of the litigation or any remedies that could be awarded in connection with the litigation. Actual results could also differ materially from expectations contained in this press release as a result of other risks and uncertainties including those related to future decisions by Dutch courts with respect to the decisions of the Dutch court referred to in this press release, the courts in Germany with respect to the preliminary injunction referred to in this press release, the strength, enforceability and validity of our patents, future revenues and the cost of litigation. These and other factors that may result in material differences from the forward-looking statements contained in this press release are discussed in greater detail in Halozyme's most recent Annual and Quarterly Reports filed with the Securities and Exchange Commission. Except as required by law, Halozyme undertakes no duty to update forward-looking statements to reflect events after the date of this release.

Contact:

Tram Bui
VP, Investor Relations and Corporate Communications
609-333-7668
[email protected] 

SOURCE Halozyme Therapeutics, Inc.