New Haven, Connecticut, July 27, 2026
Yarrow Bioscience, Inc. announced the successful completion of its merger with VYNE Therapeutics and the initiation of patient dosing in the Phase 2a/2b clinical trial of YB-101, a potential first-in-class anti-thyroid stimulating hormone receptor (TSHR) monoclonal antibody for the treatment of Graves’ disease (GD) and thyroid eye disease (TED). The company also completed previously announced private financings totaling approximately $200 million, providing an expected cash runway into 2028. Following the merger, the combined company will operate as Yarrow Bioscience and begin trading on the Nasdaq under the ticker symbol “YARW” on July 28, 2026, positioning the company to accelerate development of a novel therapy targeting the underlying cause of autoimmune thyroid diseases.
YB-101 Advances into Phase 2 Following FDA Fast Track Designation
Yarrow has initiated patient dosing in its randomized, placebo-controlled Phase 2a/2b clinical trial evaluating YB-101 in patients with Graves’ disease, with or without concurrent thyroid eye disease. The investigational therapy has received FDA Fast Track Designation, highlighting its potential to address significant unmet medical needs. Unlike current therapies, YB-101 is designed to directly block the thyroid stimulating hormone receptor (TSHR), the key disease-driving target involved in both GD and TED. The monoclonal antibody is administered subcutaneously and is being developed with the potential for infrequent dosing and future autoinjector administration. The Phase 2a proof-of-concept study will enroll approximately 32 patients, with topline data expected during the second half of 2027, while the larger Phase 2b dose-finding study is planned to begin in 2028.
Global Development Supported by Strategic Partnership in China
Yarrow’s development program is complemented by its licensing partner Changchun GeneScience Pharmaceutical Co., Ltd. (GenSci), which is advancing YB-101, also known as GenSci-098, in China. Early Phase 1 single ascending dose results in patients with thyroid eye disease demonstrated rapid, dose-dependent proof-of-mechanism, encouraging clinical responses, and a favorable safety profile, supporting progression into the ongoing multiple ascending dose (MAD) trial. Additional Phase 1 studies are also evaluating the therapy in Graves’ disease, with data from the ongoing TED trial expected in the second half of 2027. These findings are expected to help guide Yarrow’s future global development strategy for both autoimmune thyroid conditions.
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Merger and Financing Strengthen Long-Term Growth Strategy
The completion of the VYNE Therapeutics merger establishes Yarrow Bioscience as a dedicated clinical-stage biotechnology company focused exclusively on autoimmune thyroid diseases. Simultaneously, the company closed private financing transactions totaling approximately $200 million, led by RTW Investments with participation from several leading healthcare investors. Management expects these funds to support operations through 2028, enabling continued clinical development of YB-101 without near-term financing pressure. By combining a strengthened financial position, FDA Fast Track status, ongoing international clinical development, and a potential first-in-class mechanism targeting TSHR, Yarrow Bioscience aims to establish a new therapeutic approach for patients with Graves’ disease and thyroid eye disease, two autoimmune disorders with limited treatment options.
Source: Yarrow Bioscience press release
