GenSci, RTW Investments, and Yarrow Bioscience Enter Strategic Global Partnership to Advance First-in-Class Anti-TSHR Antibody for Graves’ Disease and Thyroid Eye Disease
SHANGHAI & NEW YORK Shanghai Scizeng Medical Technology Co LTD, a subsidiary of Changchun GeneScience Pharmaceutical (“GenSci”), together with RTW Investments, LP (“RTW”) and Yarrow Bioscience, Inc.Yarrowtoday announced a landmark strategic collaboration centered on the global ex-China development and commercialization of GS-098 (also known as YB-101), a clinical-stage, first-in-class monoclonal antibody designed to treat Graves’ disease (GD) and thyroid eye disease (TED).
The partnership brings together GenSci’s established innovation capabilities and deep expertise in endocrinology with RTW’s life-cycle investment leadership and Yarrow’s focused mission to develop transformative therapies for autoimmune thyroid disorders. Collectively, the collaboration aims to build a leading, U.S.-based biotechnology company dedicated to addressing significant unmet medical needs among patients suffering from autoimmune and endocrine diseases.
A Strategic Alliance With Global Ambitions
Under the terms of the agreement, Yarrow Bioscience has been granted exclusive global rights outside of China to develop, manufacture, and commercialize GS-098 (YB-101) for the treatment of Graves’ disease and thyroid eye disease. GenSci will retain full rights for the development and commercialization of GS-098 within China, ensuring continued leadership in its domestic market while expanding the therapy’s global reach through its partners.
As part of the transaction, GenSci will receive a $70 million non-refundable upfront payment, along with a $50 million near-term development milestone. In addition, GenSci is eligible to receive further development, regulatory, and commercial milestone payments, bringing the total potential deal value to up to $1.365 billion. The agreement also includes tiered double-digit royalties on future net sales in licensed territories.
This comprehensive financial and operational structure reflects strong confidence in the scientific potential of GS-098 and underscores the shared commitment of all parties to advancing the therapy toward regulatory approval and broad patient access.
GS-098 (YB-101): A Targeted Approach to Autoimmune Thyroid Disease
GS-098, which will continue development under the name YB-101 outside of China, is a humanized monoclonal antibody targeting the thyroid-stimulating hormone receptor (TSHR). TSHR plays a central role in the pathophysiology of Graves’ disease and thyroid eye disease, where pathogenic autoantibodies abnormally activate the receptor, driving excessive thyroid hormone production and inflammatory orbital tissue changes.
By selectively binding to TSHR, YB-101 is designed to block autoantibody-induced receptor activation, thereby inhibiting the underlying biological mechanisms responsible for hyperthyroidism and orbitopathy. This targeted mode of action differentiates YB-101 from existing therapeutic approaches that often rely on systemic immunosuppression or symptomatic management.
The precision of YB-101’s mechanism has the potential to deliver meaningful clinical benefits while minimizing off-target effects and avoiding broad immune suppression, which is particularly important for patients requiring long-term disease management.
Addressing Significant Unmet Needs in Graves’ Disease and TED
Graves’ disease is the most common cause of hyperthyroidism worldwide, affecting millions of individuals and often resulting in debilitating symptoms such as weight loss, tremors, heat intolerance, and cardiovascular complications. Thyroid eye disease, a frequent and severe manifestation of Graves’ disease, can lead to eye bulging, double vision, pain, inflammation, and in severe cases, permanent vision loss.
Despite the prevalence and severity of these conditions, treatment options remain limited. Many current therapies do not directly address the root autoimmune drivers of disease and may be associated with substantial side effects or invasive interventions.
The development of YB-101 represents a significant step toward disease-modifying therapy in autoimmune thyroid disorders, offering the potential to redefine treatment standards for patients who currently face few effective options.
Building a U.S.-Based Biotech Platform
Yarrow Bioscience was established with the singular mission of developing innovative therapies for autoimmune thyroid diseases. Backed by RTW Investments, a leading global life sciences investment firm based in New York, Yarrow is positioned to leverage deep scientific expertise, operational excellence, and long-term capital support to advance YB-101 efficiently through clinical development.
RTW’s involvement extends beyond financial backing, reflecting its company-creation model focused on building high-impact biotechnology enterprises capable of delivering transformative medicines to patients worldwide.
Leadership Perspectives on the Collaboration
Dr. Lei Jin, Founder, General Manager, and Chief Scientist of GenSci, and General Manager of Changchun High-Tech Industry Group, emphasized the strategic importance of the partnership.
This landmark partnership with RTW Investments and Yarrow Bioscience represents a critical step forward in our vision of becoming a global pharmaceutical innovator,” said Dr. Jin. “GS-098 originated from our Shanghai R&D center and stands as a first-in-class molecule with demonstrated best-in-class potential. Our partners bring deep experience in immunology drug development and a strong commitment to advancing GS-098 in ex-China markets. Together, we are confident that our combined expertise and resources will accelerate the delivery of this breakthrough therapy to patients with Graves’ disease and thyroid eye disease worldwide.”
Rebecca Frey, Pharm.D., President and Chief Executive Officer of Yarrow Bioscience, highlighted the transformative potential of the program.
This collaboration represents a tremendous opportunity to advance GS-098, now known as YB-101 outside of China, toward meaningful clinical milestones in both Graves’ disease and thyroid eye disease,” said Dr. Frey. “Patients living with these debilitating autoimmune conditions continue to face substantial unmet needs. YB-101’s highly targeted, TSHR-directed mechanism of action has the potential to reshape the treatment landscape, and we look forward to working closely with GenSci to bring this promising therapy to patients around the world.”
Peter Fong, Partner and President of RTW Investments, underscored the broader significance of the alliance.
Our partnership with GenSci reflects RTW’s commitment to advancing high-impact science through long-term, collaborative company creation,” said Fong. “We are dedicated to building world-class biotechnology companies, and Yarrow exemplifies this mission in action. The Yarrow leadership team brings exceptional scientific and operational expertise, and we are excited to support the advancement of GS-098 and help realize its full potential for patients.”
GenSci’s Expanding Global Footprint
Founded in 1997, GenSci is a subsidiary of Changchun High-Tech Industries Co., Ltd. and is recognized as one of China’s leading fully integrated biopharmaceutical companies. The company maintains a broad and innovative pipeline spanning endocrinology, immune and pulmonary diseases, oncology, and women’s health. GenSci also holds a strong commercial leadership position in recombinant human growth hormone (rhGH) products.
With GS-098 emerging from its Shanghai R&D center, GenSci continues to demonstrate its ability to generate globally competitive innovation while strategically partnering to expand international development and commercialization capabilities.
Looking Ahead
The collaboration between GenSci, RTW Investments, and Yarrow Bioscience marks a pivotal moment in the development of targeted therapies for autoimmune thyroid diseases. With clearly defined global responsibilities, robust financial support, and shared scientific vision, the partnership is well positioned to accelerate the advancement of YB-101 through clinical development and toward regulatory approval.
As development progresses, the alliance aims not only to deliver a novel treatment option but also to establish a new paradigm in the management of Graves’ disease and thyroid eye disease—bringing hope to patients worldwide who continue to face limited therapeutic choices.
About GS-098 (YB-101)
GS-098 (YB-101) is a clinical-stage, humanized monoclonal antibody targeting the thyroid-stimulating hormone receptor (TSHR). The antibody is designed to rapidly and efficiently block the pathogenic activity of thyroid-stimulating autoantibodies that drive disease progression in Graves’ disease (GD) and thyroid eye disease (TED). By binding selectively to the TSH receptor and blocking autoantibody-induced receptor activation, YB-101 directly inhibits the biological pathway responsible for hyperthyroidism and orbitopathy. This novel and targeted approach represents a potential breakthrough for patients who are inadequately controlled with first-line therapies and remain at high risk for complications of GD and TED. In 2025 Yarrow executed an exclusive license agreement with Changchun GeneScience Pharmaceutical Co., Ltd. to obtain global ex-China rights to develop GS-098 in GD and TED.
About Changchun GeneScience Pharmaceutical Co., Ltd. (“GenSci”)
GenSci is a leading biopharmaceutical company in China, specializing in pediatric and women’s health. Additionally, GenSci is active in four other therapeutic areas: Endocrinology, Metabolic, Immunology/Respiratory, and Oncology. The company has over 9,000 employees, and integrates research, development, production, and commercialization of innovative therapies for patients with unmet medical needs. Established in 1996, the company is a subsidiary of Changchun High‑Tech Industries Co., Ltd and is headquartered in Changchun, China.
About RTW Investments, LP
RTW Investments, LP is a New York-based, global, full life-cycle investment firm that focuses on identifying transformational and disruptive innovations across the biopharmaceutical and medical technologies sectors. As a leading partner of industry and academia, RTW combines deep scientific expertise with a solution-oriented investment approach to advance emerging therapies by building and supporting the companies developing them.
About Yarrow Bioscience, Inc.
Yarrow Bioscience is a clinical-stage biotechnology company focused on developing transformative therapies for autoimmune thyroid diseases. The company’s lead candidate, YB-101, is a humanized monoclonal antibody targeting the thyroid-stimulating hormone receptor (TSHR) for the treatment of Graves’ disease and thyroid eye disease. Yarrow is headquartered in New York and is backed by leading healthcare investor RTW Investments, LP.
