Merus and Halozyme Enter Global Collaboration and License Agreement to Develop Subcutaneous Formulation of Petosemtamab

Rhea-AI Summary

Merus (Nasdaq: MRUS) and Halozyme (Nasdaq: HALO) announced a global non-exclusive collaboration and license agreement on November 17, 2025 to develop a subcutaneous formulation of petosemtamab using Halozyme's ENHANZE® drug delivery technology.

Merus licensed ENHANZE® for development and potential commercialization of petosemtamab, an EGFR x LGR5 bispecific antibody that is in clinical studies for multiple solid tumors including recurrent/metastatic head and neck squamous cell carcinoma (r/m HNSCC). Terms include an upfront payment, potential commercial and sales-based milestone payments, and low‑mid single digit royalties on net sales of the ENHANZE®-formulated product.

Insights

Biotech Partnerships Strategist

Merus and Halozyme partnered to pursue a subcutaneous form of petosemtamab, potentially easing administration and commercial rollout.

Merus licensed Halozyme's ENHANZE® platform to develop and potentially commercialize a subcutaneous version of petosemtamab, an EGFR x LGR5 bispecific antibody, expanding formulation options for an intravenously dosed oncology candidate. The agreement includes an upfront payment, future commercial/milestone payments, and royalties described as up to low-mid single digit% on net sales of the ENHANZE-formulated product.

This deal changes the product's route‑of‑administration economics and patient experience by enabling outpatient or clinic-based dosing and potentially lowering infusion infrastructure needs. Key dependencies include successful formulation work, comparable pharmacokinetics and safety for the subcutaneous route, and regulatory acceptance of the new formulation for the same indications.

Watch for formulation and clinical bridging data, regulatory filing steps, and any disclosure of the upfront and milestone economics; these items will clarify commercial value and timeline. Expect preliminary formulation or bridging data within typical formulation-development windows, with commercial impacts realized only if regulatory approvals permit substitution or separate approval for the subcutaneous presentation.

SAN DIEGO and UTRECHT, The Netherlands and CAMBRIDGE, Mass., Nov. 17, 2025 /PRNewswire/ -- Merus N.V. (Nasdaq: MRUS) ("Merus"), an oncology company developing innovative, full-length multispecific antibodies and antibody drug conjugates (Biclonics^®, Triclonics^® and ADClonics^®), and Halozyme Therapeutics, Inc. (Nasdaq: HALO) ("Halozyme"), a leader in subcutaneous drug delivery solutions, today announced they have entered into a global non-exclusive collaboration and license agreement. Under the collaboration, Merus has licensed Halozyme's ENHANZE^® drug delivery technology, for the development and potential commercialization of subcutaneous administration of petosemtamab, an EGFR x LGR5 bispecific antibody.

"Petosemtamab continues to show encouraging results in the clinical studies across numerous solid tumor cancers and has the potential to become a first and best in class treatment in head and neck cancer and beyond. We are proud to collaborate with Halozyme and look forward to working closely with their team on a subcutaneous administration," said Peter Silverman, Chief Operating Officer, General Counsel of Merus.

"We are excited to collaborate with Merus to advance treatment options for patients with r/m HNSCC and other potential indications," said Dr. Helen Torley, President and Chief Executive Officer of Halozyme. "This collaboration represents a new opportunity for our ENHANZE^® technology to improve treatment efficiency and enhance the patient treatment experience. Together, we aim to accelerate innovation for patients and healthcare providers."

Under the terms of the agreement, Merus will make an upfront payment to Halozyme, and potential future milestone payments related to commercial and sales attainment, if approved. Halozyme will also be entitled to up to low-mid single digit royalties on net sales of petosemtamab formulated with the ENHANZE^® technology during the royalty term.

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 is used to facilitate the subcutaneous delivery of injected drugs and fluids, with the goal of improving the patient experience with rapid subcutaneous delivery and reduced treatment burden. Having touched one million patient lives in post-marketing use in ten commercialized products in at least one major region and across more than 100 global markets, Halozyme has licensed its ENHANZE^® technology to leading pharmaceutical and biotechnology companies including Roche, Takeda, Pfizer, Janssen, AbbVie, Eli Lilly, Bristol-Myers Squibb, argenx, ViiV Healthcare, Chugai Pharmaceutical and Acumen Pharmaceuticals.

Halozyme also develops, manufactures and commercializes, for itself or with partners, drug-device combination products using its advanced auto-injector technologies that are designed to provide commercial or functional advantages such as improved convenience, reliability and tolerability, and enhanced patient comfort and adherence. The Company has two commercial proprietary products, Hylenex^® and XYOSTED^®, partnered commercial products and ongoing product development programs with Teva Pharmaceuticals and McDermott Laboratories Limited, an affiliate of Viatris Inc.

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

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

Ab out Merus N.V.

Merus is an oncology company developing innovative full-length human bispecific and trispecific antibody therapeutics, referred to as Multiclonics^®. Multiclonics^® are manufactured using industry standard processes and have been observed in preclinical and clinical studies to have several of the same features of conventional human monoclonal antibodies, such as long half-life and low immunogenicity. For additional information, please visit Merus' website and LinkedIn.

Merus Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding our belief that petosemtamab' results in the clinical studies of numerous solid tumor cancers; petosemtamab's potential to become a first and best in class treatment in head and neck cancer and beyond; the future performance under the global non-exclusive collaboration and license agreement with Halozyme and development of subcutaneous administration of petosemtamab; the timing of such development; the opportunity of the ENHANZE^® technology to improve treatment efficiency and enhance the patient treatment experience; the potential future milestone payments or royalties related to commercial and sales attainment, if approved; the clinical development of our clinical candidates, including petosemtamab, future clinical trial results or interim data, clinical activity and safety profile, and development plans in the on-going trials. These forward-looking statements are based on management's current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: our need for additional funding, which may not be available and which may require us to restrict our operations or require us to relinquish rights to our technologies or antibody candidates; potential delays in regulatory approval, which would impact our ability to commercialize our product candidates and affect our ability to generate revenue; the lengthy and expensive process of clinical drug development, which has an uncertain outcome; the unpredictable nature of our early stage development efforts for marketable drugs; potential delays in enrollment of patients, which could affect the receipt of necessary regulatory approvals; our reliance on third parties to conduct our clinical trials and the potential for those third parties to not perform satisfactorily; impacts of the volatility in the global economy, including global instability, including the ongoing conflicts in Europe and the Middle East; we may not identify suitable Biclonics^® or bispecific antibody candidates under our collaborations or our collaborators may fail to perform adequately under our collaborations; our reliance on third parties to manufacture our product candidates, which may delay, prevent or impair our development and commercialization efforts; protection of our proprietary technology; our patents may be found invalid, unenforceable, circumvented by competitors and our patent applications may be found not to comply with the rules and regulations of patentability; we may fail to prevail in potential lawsuits for infringement of third-party intellectual property; and our registered or unregistered trademarks or trade names may be challenged, infringed, circumvented or declared generic or determined to be infringing on other marks.

These and other important factors discussed under the caption "Risk Factors" in our Quarterly Report on Form 10-Q for the period ended September 30, 2025, filed with the Securities and Exchange Commission, or SEC, on October 31, 2025, and our other reports filed with the SEC, could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management's estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change, except as required under applicable law. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release.

Multiclonics^®, Biclonics^®, Triclonics^®, and ADClonics^® are registered trademarks of Merus N.V. 

Halozyme Forward-Looking Statements

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 ENHANZE^®, the possible method of action of ENHANZE^®, its potential application to aid in the dispersion and absorption of other injected therapeutic drugs and statements concerning certain other potential benefits of ENHANZE^® including facilitating more rapid delivery and administration of larger volumes of injectable medications through subcutaneous delivery and potentially lowering the treatment burden and improving the treatment experience for patients. These forward-looking statements also include statements regarding the product development and commercialization efforts of Halozyme's ENHANZE^® partner (including the potential regulatory approval and launch of ENHANZE^® products as a result of such efforts and the potential future market opportunity for such products) and Halozyme's potential receipt of an upfront payment and payments associated with achievement of certain development, regulatory and sales-based milestones, and royalties on sales of commercialized products. These forward-looking statements involve risks and uncertainties 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 "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, including risks and uncertainties concerning whether development, regulatory and sales-based milestones will be achieved, uncertainties concerning whether collaborative products are ultimately developed, approved or commercialized and the potential future market for such products, unexpected expenditures and costs, unexpected results or delays in development and regulatory review, unexpected regulatory approval requirements, unexpected adverse events or patient outcomes and competitive conditions. These and other factors that may result in differences 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.

Investor and Media Inquiries

Sherri Spear
Merus N.V.
SVP Investor Relations and Strategic Communications
617-821-3246
s.spear@merus.nl 

Kathleen Farren
Merus N.V.
Director Investor Relations and Corporate Communications
617-230-4165
k.farren@merus.nl 

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

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SOURCE Halozyme Therapeutics, Inc.

FAQ

What did Halozyme and Merus announce on November 17, 2025 regarding HALO and MRUS?

They announced a global non-exclusive collaboration and license to use Halozyme's ENHANZE® technology to develop a subcutaneous formulation of petosemtamab.

How will Halozyme be paid under the HALO license with Merus for petosemtamab?

Merus will make an upfront payment, potential future commercial and sales-based milestone payments, and pay up to low‑mid single digit royalties on net sales of the formulated product.

What is petosemtamab and which indications are mentioned in the Merus–Halozyme deal?

Petosemtamab is an EGFR x LGR5 bispecific antibody in clinical studies for numerous solid tumors, including recurrent/metastatic head and neck squamous cell carcinoma (r/m HNSCC).

Is the Halozyme ENHANZE® license exclusive for petosemtamab under the agreement?

No, the agreement is described as a global non-exclusive collaboration and license.

What potential patient benefit does the HALO and Merus collaboration aim to deliver for HALO shareholders?

The collaboration aims to enable subcutaneous administration of petosemtamab, which could improve treatment efficiency and the patient treatment experience if developed and approved.