BioMarin Licenses Subcutaneous Fabry ERT from GC, Hanmi

BioMarin has signed an exclusive worldwide licence (excluding Korea) for HM15421/GC1134A, a long-acting subcutaneous enzyme replacement therapy (ERT) for Fabry disease, from GC Biopharma and Hanmi Pharm, in a deal worth up to $475m. Announced on 29 October 2026, the agreement delivers a potentially first-in-class subcutaneous ERT candidate into BioMarin’s rare disease pipeline and extends the company’s commercial strategy following its $4.8bn Amicus Therapeutics acquisition earlier in 2026.

The deal pays $70m upfront, up to $405m in development and commercial milestones shared by GC Biopharma and Hanmi Pharm, and tiered royalties on net sales. GC Biopharma and Hanmi retain commercialisation rights in Korea. HM15421/GC1134A is a long-acting recombinant α-Gal A enzyme replacement therapy delivered subcutaneously and engineered for extended half-life and improved stability. Fabry disease is an X-linked lysosomal storage disorder caused by GLA variants that reduce α-Gal A activity, leading to the buildup of globotriaosylceramide (GL-3), associated with pain, kidney failure and elevated cardiovascular risk. The asset holds FDA orphan drug designation from 2024.

A Phase 1/2 open-label, nonrandomised proof-of-concept study (NCT06858397), sponsored by GC Biopharma with Hanmi as collaborator, plans to enrol 18 adults across low, mid and high subcutaneous dose cohorts, with safety as the primary endpoint over 48 weeks. Following completion, BioMarin will take over development, manufacturing and commercialisation outside Korea. BioMarin CEO Alexander Hardy positioned the candidate as potentially offering a new way of treating Fabry disease. The deal expands BioMarin’s rare disease pipeline following the Amicus acquisition, which brought oral migalastat (Galafold) into the portfolio for Fabry patients whose GLA mutations are amenable to the pharmacological chaperone approach. A subcutaneous ERT would address the substantial subset of Fabry patients whose mutations do not respond to oral migalastat, extending the addressable patient population. No clinical efficacy or safety data have yet been reported; efficacy signals to date come from preclinical studies.

The commercial signal is a maturing Fabry disease therapeutic category where a potentially first-in-class subcutaneous ERT could reshape patient treatment experience against incumbent intravenous ERT standards and complement the oral chaperone pathway. Phase 1/2 safety readout is the next critical milestone. Expect sustained BioMarin pipeline expansion through 2027 and continued focus on rare disease delivery mechanism differentiation.

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