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RTW Biotech Invests in Yarrow before Nasdaq Merger

Bio Tech

Business Honor
19 December, 2025

RTW invests $5.9M in Yarrow to advance autoimmune thyroid treatments through YB-101, a merger with VYNE, and licensing deal.

RTW Biotech Opportunities Ltd announced that it had invested in the Series A funding round of medical-stage biotechnology company Yarrow Bioscience Inc., before its scheduled Nasdaq IPO. The Guernsey-based investor committed USD 5.9 million, or 0.7% of its total assets value. Yarrow Bioscience, RTW’s eighth company, develops treatments for autoimmune thyroid diseases. Its main study, YB-101, aims to reduce the harmful activity of thyroid-stimulating antibodies that cause disease development in Graves' disease and thyroid eye disease.

Earlier this week, RTW and Yarrow signed a global ex-China license agreement for YB-101 with Shanghai Scizeng Medical Technology, an affiliate of Changchun GeneScience Pharmaceuticals. The partnership aims to create a biotech platform in the US in order to help patients with endocrine and autoimmune disorders. Yarrow also announced a deal to merge with New Jersey-based biotech VYNE Therapeutics Inc., that's expected for completion in the second quarter of next year. The new business will be known as Yarrow Bioscience Inc. and will trade on the Nasdaq exchange. To support the arrangement, RTW Investments LP and OrbiMed Advisors have invested about USD 200 million in advance financing.

RTW Chief Investment Officer Roderick Wong stated, "Yarrow's partnership with GenSci and merger with VYNE position the company to increase therapy choices for patients with Graves' illness and thyroid eye condition. Yarrow's leadership brings outstanding scientific and operational expertise, so we look forward to realizing YB-101's full potential." With this funding and partnerships, Yarrow Bioscience will transform treatment options for autoimmune thyroid illnesses, a new patient-focused biotechnology and personalized medicine.