BioMarin Enters Into Exclusive Worldwide License Agreement With GC Biopharma and Hanmi Pharm for Investigational Next-Generation Enzyme Replacement Therapy, Adding a Second Potential Treatment for Fabry Disease

Agreement grants BioMarin worldwide rights (excluding Korea) to HM15421/GC1134A, a long-acting, subcutaneous, clinical-stage enzyme replacement therapy for Fabry disease

BioMarin will make an upfront payment of $70 million; GC and Hanmi will be jointly eligible to receive additional payments upon certain development and commercial milestones, and tiered royalties on net sales of HM15421/GC1134A

SAN RAFAEL, Calif., Oct. 29, 2026 /PRNewswire/ -- BioMarin Pharmaceutical Inc. (Nasdaq: BMRN) today announced it has entered into an exclusive worldwide license agreement with GC Biopharma Corp. and Hanmi Pharm Co., Ltd. to develop and commercialize HM15421/GC1134A, an investigational long-acting enzyme replacement therapy for Fabry disease.

HM15421/GC1134A is a human recombinant alpha-galactosidase A (a-Gal A) enzyme therapy currently being studied in a Phase 1/2 clinical trial in people living with Fabry disease and has the potential to be the first subcutaneous enzyme replacement therapy for Fabry disease.

"This agreement reflects our growing commitment to the Fabry community, building on the acquisition of Amicus earlier this year," said Alexander Hardy, President and Chief Executive Officer of BioMarin. "HM15421/GC1134A has the potential to offer a new way of treating Fabry disease, and we believe it could be an important option for patients. As we continue to add to our clinical portfolio, both through internal research and external programs, HM15421/GC1134A is an excellent fit and could allow us to reach a new generation of patients with Fabry beyond those with mutations amenable to treatment with GALAFOLD."

Under the terms of the agreement, BioMarin will make an upfront payment of $70 million. GC and Hanmi are also jointly eligible to receive up to an additional $405 million upon the completion of certain development and commercial milestones, and tiered royalties.

In preclinical studies, HM15421/GC1134A demonstrated differentiated efficacy across key measures, including renal function, vascular health and peripheral nervous system outcomes. The candidate received Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) in 2024. Following the ongoing Phase 1/2 study, BioMarin will assume sole responsibility for all subsequent clinical development, manufacturing and commercialization of HM15421/GC1134A outside of Korea. GC and Hanmi will retain commercialization rights for HM15421/GC1134A in Korea.

About Fabry Disease
Fabry disease is a lysosomal storage disorder caused by inherited genetic changes in the GLA gene, which hampers activity of the enzyme alpha-galactosidase A (a-Gal A). Reduced a-Gal A activity leads to lysosomal accumulation of globotriaosylceramide (GL-3), which is believed to cause the various symptoms of Fabry disease, including pain, kidney failure and increased risk of heart attack and stroke. The symptoms can be severe, differ from person to person, and begin at an early age.

About HM15421/GC1134A
HM15421/GC1134A is an investigational, long-acting enzyme replacement therapy for Fabry disease, a rare, X-linked lysosomal storage disorder caused by deficient alpha-galactosidase A activity. HM15421/GC1134A is designed to extend half-life and improve stability relative to currently available enzyme replacement therapies, supporting subcutaneous dosing. HM15421/GC1134A is currently being evaluated in a Phase 1/2 clinical trial.

About BioMarin
BioMarin is a leading, global rare disease biotechnology company focused on delivering medicines for people living with genetically defined conditions. Founded in 1997, the San Rafael, California-based company has a proven track record of innovation, with nine commercial therapies and a strong clinical and preclinical pipeline. Using a distinctive approach to drug discovery and development, BioMarin seeks to unleash the full potential of genetic science by pursuing category-defining medicines that have a profound impact on patients. To learn more, please visit www.biomarin.com.

Forward-Looking Statements
This press release contains forward-looking statements about the business prospects of BioMarin Pharmaceutical Inc. (BioMarin), including without limitation, statements about: the plans and expectations regarding the exclusive worldwide license agreement with GC Biopharma Corp. and Hanmi Pharm Co., Ltd. to develop and commercialize HM15421/GC1134A for Fabry disease; expectations regarding HM15421/GC1134A, including commercial prospects, potential benefits of HM15421/GC1134A for patients with Fabry disease, and the potential to be the first subcutaneous treatment for Fabry disease; and prospects and timing of actions relating to preclinical and clinical studies and approvals. These forward-looking statements are predictions and involve risks and uncertainties such that actual results may differ materially from these statements. These risks and uncertainties include, among others, results and timing of current and planned preclinical studies and clinical trials and the release of data from those trials; any potential adverse events observed in the continuing monitoring of the patients in the clinical trials; the content and timing of decisions by the U.S. Food and Drug Administration, the European Medicines Agency, the European Commission and other regulatory authorities; and those factors detailed in BioMarin's filings with the Securities and Exchange Commission, including, without limitation, the factors contained under the caption "Risk Factors" in BioMarin's Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, as such factors may be updated by any subsequent reports. Investors are urged not to place undue reliance on forward-looking statements, which speak only as of the date hereof. BioMarin is under no obligation, and expressly disclaims any obligation to update or alter any forward-looking statement, whether as a result of new information, future events or otherwise.

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SOURCE BioMarin Pharmaceutical Inc.