Yarrow lands $1.37B China biotech deal, betting on first-in-class TSHR antibody for thyroid disease
U.S.-based Yarrow Bioscience has secured its lead asset through a potential $1.37 billion licensing deal with China’s GenSci Pharmaceutical, picking up ex-China rights to a first-in-class antibody targeting autoimmune thyroid disease as it charts a broader expansion beyond its early platform roots.
The agreement announced this Monday grants GenSci subsidiary Shanghai Scizeng Medical Technology $70 million upfront and $50 million in near-term development milestones. Additional development, regulatory, and commercial milestones could increase the total deal value to $1.365 billion, with tiered double-digit royalties on future sales outside of China.
The asset, GS-098 to be renamed YB-101 by Yarrow, is a monoclonal antibody designed to block activation of the thyroid-stimulating hormone receptor (TSHR), a central driver of Graves’ disease and thyroid eye disease (TED). By preventing autoantibody-induced signaling, the drug aims to suppress excess thyroid hormone production, limit thyroid cell proliferation, reduce inflammatory pathways linked to hyperthyroidism and orbital disease.
GS-098 is already clinically enabled. GenSci received regulatory clearance in both the U.S. and China in August 2024 to begin trials in thyroid eye disease, followed by authorization in October 2025 to initiate studies in Graves’ disease in China, providing Yarrow with a development-ready entry point rather than a preclinical reset.
The deal marks a strategic pivot into autoimmune endocrinology with a differentiated mechanism. CEO Rebecca Frey framed the program as a potential disease-modifier, arguing that TSHR blockade could meaningfully reshape treatment paradigms in conditions long dominated by symptomatic management and steroids.
TSHR has emerged as a high-interest target across biotech, driven by the commercial success of Amgen’s Tepezza in thyroid eye disease and the search for next-generation options with broader utility and improved safety. Several U.S. startups, including Ollin Biosciences, Crinetics, Merida Therapeutics, and Septerna, are pursuing TSHR-related strategies, though most remain in preclinical development.
The deal broadens the China-to-West licensing wave, as established Chinese pharma groups increasingly monetize innovative pipelines globally. GenSci’s parent, Changchun High-Tech, joins peers such as Fosun, Hengrui, and Sino Biopharma in leveraging domestic R&D to strike multibillion-dollar international partnerships.
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As year-end dealmaking accelerates, Yarrow’s move underscores investors’ willingness to back focused biotechs with late-enabling assets, particularly in autoimmune disease, where first-in-class biology and clear regulatory paths continue to command premium valuations.
