Halozyme Wins Preliminary Injunction Against Merck's Keytruda SC in Germany

Rhea-AI Summary

Halozyme (NASDAQ: HALO) said a German court granted a preliminary injunction on Dec 4, 2025 ordering Merck to stop distributing and offering Keytruda SC in Germany for activity that would infringe European Patent No. 2 797 622 (EP 622) covering Halozyme's MDASE technology.

The order halts Merck's German launch activities within the injunction's scope; the decision is appealable and separate nullity proceedings filed by Merck in Aug 2025 are pending. Halozyme said Keytruda IV remains available and reiterated ongoing U.S. litigation alleging U.S. subcutaneous Keytruda (marketed as QLEX) infringes multiple MDASE patents.

Positive

• German court granted a preliminary injunction halting Keytruda SC launch
• Injunction cites imminent infringement of European Patent No. 2 797 622
• U.S. litigation alleges QLEX infringes 15 Halozyme MDASE patents

Negative

• Court decision is appealable, leaving outcome uncertain
• Nullity proceedings against EP 622 are pending since August 2025
• Injunction applies only to Germany; Keytruda IV remains available

Key Figures

European patent number EP 2 797 622 MDASE patent cited in German preliminary injunction

Patents alleged infringed 15 patents U.S. lawsuit over Keytruda SC (QLEX) subcutaneous formulation

Patent filing start 2011 Year Halozyme began filing MDASE technology patents

Hyaluronidase modifications Nearly 7,000 modifications Research underpinning MDASE human hyaluronidase platform

Pre-news price change -2.83% Move in 24h before injunction headline

52-week range $46.26–$79.50 Pre-news trading range; current price 18.7% below high

Market cap $7.82B Equity value before German injunction news

200-day MA $63.07 Shares trading modestly above this level pre-news

Market Reality Check

$64.66 Last Close

Volume Volume 2.72M is 3% above the 20-day average (2.64M) normal

Technical Trading 2.5% above 200-day MA ($64.66 vs. $63.07) and 18.7% below 52-week high

Peers on Argus

Before this news, HALO was down 2.83% while key biotech peers in its sector snapshot (e.g., MRNA +4.7%, ROIV +2.42%, RVMD +2.83%) mostly traded higher, indicating stock-specific pressure rather than a sector-wide move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Nov 25	Conference participation	Neutral	-1.6%	Announcement of participation and webcast at Evercore healthcare investor conference.
Nov 18	Acquisition deal	Positive	-0.7%	Completion of Elektrofi acquisition adding Hypercon formulation platform and milestones.
Nov 17	New collaboration	Positive	+0.8%	Global ENHANZE license deal with Merus for subcutaneous petosemtamab.
Nov 07	FDA approval-linked	Positive	-0.2%	FDA approval of DARZALEX Faspro with ENHANZE for high-risk smoldering myeloma.
Nov 06	Convertible notes	Neutral	-0.2%	Pricing of 2031 and 2032 convertible notes to refinance debt and fund general uses.

Pattern Detected

Recent history shows several positive strategic or regulatory updates followed by flat-to-negative price reactions, suggesting a tendency for the stock to underperform around ostensibly favorable news.

Recent Company History

Over the last month, Halozyme reported stronger Q3 results on Nov 3, amended its credit facility and launched new convertibles, and later completed a $1.5B note financing. It also gained an FDA approval-linked ENHANZE® milestone on Nov 7, announced a new ENHANZE® collaboration with Merus on Nov 17, and closed the Elektrofi acquisition on Nov 18. Despite generally positive strategic progress, 24-hour price moves around these events were mostly modest and often negative, similar to the pre-news -2.83% move today.

Regulatory & Risk Context

Short Interest

10.11%

0% 15% 30%+

moderate

Short interest at 10.11% of float with 5.74 days to cover suggests a moderately crowded short position that could amplify reactions to material legal or patent developments, in either direction.

Market Pulse Summary

This announcement highlights a preliminary injunction from a German court blocking Merck’s Keytruda SC launch activities that allegedly infringe Halozyme’s MDASE™ patent EP 2 797 622, while leaving IV Keytruda unaffected. It fits into Halozyme’s broader patent-enforcement campaign, including a U.S. suit over 15 MDASE-related patents. The news underlines the strategic importance of Halozyme’s subcutaneous delivery IP, but also the ongoing appeal and nullity proceedings that could affect the durability of this legal position.

Key Terms

preliminary injunction regulatory

"a German court has granted its request for a preliminary injunction ordering Merck"

A preliminary injunction is a court order that temporarily stops a party from taking certain actions while a legal case is ongoing. It’s like a warning sign that prevents someone from moving forward with plans that could cause harm or unfair advantage until the court makes a final decision. For investors, it signals that there may be unresolved legal issues affecting the parties involved, which can impact a company's operations or value.

nullity proceedings regulatory

"Separate nullity proceedings against this patent initiated by Merck in August 2025"

Nullity proceedings are legal processes used to declare a contract or agreement invalid and without legal effect, as if it never existed. They are important to investors because they can determine whether a financial arrangement or corporate action is legally binding, potentially affecting the validity of investments or transactions. Think of it as a court ruling that cancels a deal, making it as if it never happened.

subcutaneous medical

"subcutaneous formulation of Keytruda, which is being marketed in the U.S. as QLEX"

Subcutaneous means situated or applied just beneath the skin. In finance, the term can describe processes or investments that are hidden or not immediately visible, much like something placed under the skin that isn't easily seen from the outside. Recognizing subcutaneous activities helps investors understand underlying factors that may influence markets or asset values over time.

AI-generated analysis. Not financial advice.

SAN DIEGO, Dec. 4, 2025 /PRNewswire/ -- Halozyme Therapeutics, Inc. (NASDAQ: HALO) (Halozyme), announced today that a German court has granted its request for a preliminary injunction ordering Merck to refrain from distributing and offering Keytruda SC in Germany.

The Munich Regional Court's 7th Civil Division found that there is imminent infringement for Keytruda SC in Germany regarding one of Halozyme's MDASE™ patents in Europe, European Patent No. 2 797 622 (EP 622). As a consequence, Merck's launch activities for Keytruda SC in Germany that are within the scope of the order must be halted. Although the preliminary injunction decision is appealable, Halozyme believes the order will withstand attack if appealed. Separate nullity proceedings against this patent initiated by Merck in August 2025 are pending before the German Federal Patent Court.

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

"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. 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. "We are committed to vigorously defending and enforcing our MDASE patents and are confident that we will prevail at trial."

The German proceedings are part of Halozyme's global enforcement of its MDASE™ patents against infringement by Merck's Keytruda SC. 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 infringement lawsuit against Merck will not impact ENHANZE^®, the ability of any licensee to use ENHANZE^®, or revenues Halozyme receives from ENHANZE^® licensees.

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, and Merus N.V.

Halozyme is also developing Hypercon™ to expand the breadth of its drug delivery technology portfolio. Hypercon™ is an innovative microparticle technology that is expected to set a new standard in hyper concentration of drugs and biologics that can reduce the injection volume for the same dosage and expands opportunities for at-home and health care provider administration. The addition of Hypercon™ enhances our ability to transform the patient treatment experience by enabling the creation and delivery of highly concentrated biologics, substantially broadening the scope of therapeutics that can be delivered subcutaneously. The Hypercon™ technology has been licensed to leading biopharmaceutical partners, including Johnson & Johnson, Eli Lilly, and argenx.

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 and Twitter.

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 the Munich Regional Court's 7th Civil Division to issue a preliminary injunction against Keytruda SC in Germany, any appeal of the preliminary injunction, nullity proceedings, 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, Corp., 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 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.

Contacts:

Tram Bui
VP, Investor Relations and Corporate Communications
609-359-3016
tbui@halozyme.com

Paul Gallagher
Teneo
917-573-5051
paul.gallagher@teneo.com

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SOURCE Halozyme Therapeutics, Inc.

FAQ

What did Halozyme announce on Dec 4, 2025 about Keytruda SC (HALO)?

A German court granted a preliminary injunction ordering Merck to stop distributing Keytruda SC in Germany for activity that would infringe EP 622.

Does the German injunction stop Keytruda IV use in Germany (HALO)?

No; the announcement says Keytruda IV is not covered by Halozyme's patent or the court's injunction.

Is the Munich injunction final or appealable for HALO vs Merck?

The injunction is appealable and Halozyme noted separate nullity proceedings are pending since August 2025.

How does the German ruling relate to Halozyme's U.S. lawsuit (HALO)?

Halozyme also sued in New Jersey, alleging the U.S. subcutaneous product QLEX infringes 15 MDASE patents.

Which patent did the Munich court find at risk of imminent infringement (HALO)?

The court cited European Patent No. 2 797 622 (EP 622) covering Halozyme's MDASE technology.