GenSci Secures Up to $1.365B in Global ex-China Licensing Deal for GS-098(YB-101) with RTW Investments

· GenSci to receive $70 million non-refundable upfront payment, a $50 million near-term development milestone, and further development, regulatory and commercial milestone payments in a total deal value up to $1.365 billion with tiered double-digit royalties on future net sales in licensed territories; GenSci retains the rights for development and commercialization of GS-098 in China

· Yarrow Bioscience, Inc. to receive exclusive global ex-China rights to develop and commercialize GS-098 (YB-101) for Graves' disease (GD) and thyroid eye disease (TED)

Shanghai, China and New York, United States – December 15, 2025 – Shanghai Scizeng Medical Technology Co., LTD, a subsidiary of Changchun GeneScience Pharmaceutical Co., Ltd. ("GenSci"), RTW Investments, LP ("RTW"), and Yarrow Bioscience, Inc. ("Yarrow") announced an exclusive global ex-China license agreement for GS-098. GS-098, which will be continued as YB-101 outside of China, is a clinical-stage, first-in-class, humanized monoclonal antibody targeting the thyroid-stimulating hormone receptor (TSHR) for the treatment of Graves' disease (GD) and thyroid eye disease (TED).  

Under the terms of the agreement, Yarrow receives exclusive global ex-China rights to develop, manufacture, and commercialize GS-098 (YB-101) for GD and TED. GenSci retains rights for development and commercialization in China. GenSci will receive a $70 million non-refundable upfront payment, a $50 million near-term development milestone, and further development, regulatory and commercial milestone payments in a total deal value up to $1.365 billion with tiered double-digit royalties on future net sales in licensed territories. 

Thyroid diseases have been a significant and expanding therapeutic area in the world. According to a report by Market Research Future (MRFR), the market size for GD is estimated to expand from $3.76 billion in 2025 to $6.04 billion by 2035. Meanwhile, the TED market size is projected to reach $2.67 billion in 2025 and is predicted to reach $5.45 billion by 2033 at a compound annual growth rate (CAGR) of 9.34%. 

"This landmark partnership with RTW Investments and Yarrow Bioscience, Inc. is a strategic step in our vision of becoming a global pharma innovator. GS-098, originated from our Shanghai R&D center, is a first-in-class molecule and has demonstrated the best-in-class potential," said Dr. Lei Jin, Founder, General Manager & Chief Scientist of GenSci and General Manager of Changchun High-Tech Industry Group. "Our partners RTW Investments and Yarrow Bioscience, Inc. have demonstrated exceptional expertise and experience in developing innovative drugs in the field of immunology and shown great commitment and passion to develop GS-098 in the ex-China territory. We believe that our combined expertise and resources will bring this breakthrough medicine to the Graves' Disease and Thyroid Eye Disease patients speedily and worldwide.” 

"This collaboration represents a tremendous opportunity for Yarrow and GenSci to advance GS-098 (YB-101) toward meaningful clinical milestones in both Graves' disease and thyroid eye disease," said Rebecca Frey, Pharm.D., President and Chief Executive Officer of Yarrow Bioscience. "Patients suffering from these debilitating autoimmune conditions continue to face substantial unmet needs. YB-101's highly targeted, TSHR-directed mechanism of action has the potential to transform the treatment landscape, and we look forward to working closely with GenSci to bring this promising therapy to patients worldwide." 

"Our partnership with GenSci reflects RTW's commitment to advancing high-impact science through long-term, collaborative company creation," said Peter Fong, Partner and President at RTW Investments, LP. "We are dedicated to building world-class biotechnology companies, and Yarrow represents a model example of this mission in action. Rebecca and the Yarrow leadership team bring exceptional scientific and operational expertise, and we look forward to working closely with them to advance GS-098 (YB-101) and realize its full potential for patients."