Yarrow Bioscience, backed by RTW Investments, struck an ex‑China licensing and development agreement with Shanghai Scizeng Medical Technology (GenSci) for GS‑098 (YB‑101), a TSHR‑targeting antibody for Graves’ disease and thyroid eye disease. Yarrow will pay $70 million up front plus $50 million in near‑term milestones and could reach up to $1.365 billion in total biobucks, the companies said in filings and releases. GenSci retains China rights; Yarrow gains global ex‑China development and commercialization control. The antibody blocks autoantibody‑driven TSHR activation and has cleared early clinical testing in China. Yarrow framed the deal as a foundational asset to build a specialty autoimmune franchise.