Marks first ENHANZE^®agreement to include ADC targets

Collaboration also includes option for additional future targets

First clinical trial projected to initiate in 2026

SAN DIEGO, May 7, 2026 /PRNewswire/ -- Halozyme Therapeutics, Inc. (NASDAQ:HALO) ("Halozyme" or the "Company") today announced the Company entered into a global collaboration and license agreement with GSK. Under the collaboration, GSK has licensed Halozyme's ENHANZE^® drug delivery technology for the development and potential commercialization of subcutaneous administration of multiple oncology targets, including antibody drug conjugates (ADCs), as well as an option for additional future drug targets.

"We are excited to work with GSK to advance development of several oncology therapeutics. This agreement also marks our first collaboration on subcutaneous delivery of ADCs, where we believe subcutaneous delivery with ENHANZE may meaningfully improve the benefit–risk profile," said Dr. Helen Torley, President and Chief Executive Officer of Halozyme. "This collaboration reflects the continued recognition of ENHANZE as the gold standard for rapid, large-volume subcutaneous delivery, and underscores the value it provides to a growing number of leading pharmaceutical and biotechnology companies. Extending use of ENHANZE with ADCs represents a meaningful expansion of our potential addressable market, positions us at the forefront of a rapidly growing therapeutic class and reinforces the durability of our high-margin royalty revenue business."

"Novel approaches are required to reduce treatment burden for patients with cancer and help access easier forms of treatment," said Eric Richards, SVP Head of Medicine Development Leaders Oncology, GSK. "We see significant potential for subcutaneous formulations of several promising cancer targets, including ADCs, with ENHANZE and look forward to progressing the first clinical program."

GSK will make an upfront payment to Halozyme and potential future milestone payments. Halozyme will also be entitled to royalties on net sales of products that incorporate ENHANZE^®.

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. and Skye Bioscience.

Halozyme expanded its drug delivery technology portfolio to develop partner products using Hypercon™ and Surf Bio's hyperconcentration technology. 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. The addition of Surf Bio'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 Surf Bio's technology 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.

Forward Looking Statements

In addition to historical information, the statements set forth above include forward-looking statements including, without limitation, statements concerning royalty revenue growth, margins and durability, potential new partnerships and innovations, 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, easing treatment access and improving the treatment experience for patients. These forward-looking statements also include statements regarding the product development and commercialization efforts of GSK (including the potential advancement and timing of the initiation of the clinical program, regulatory approval and launch as a result of such efforts and the potential future market opportunity for such products) and Halozyme's potential receipt of payments associated with achievement of certain 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 "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, 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 levels of revenue growth, 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.

Contacts:

Tram Bui

VP, Investor Relations and Corporate Communications

609-333-7668

tbui@halozyme.com

Sydney Charlton

Teneo

917-972-8407

sydney.charlton@teneo.com

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SOURCE Halozyme Therapeutics, Inc.

Halozyme Announces Global Collaboration and License Agreement with GSK to Develop Subcutaneous Formulations of Multiple Promising Oncology Targets