RTW-backed startup Yarrow Bioscience signs autoimmune antibody deal with China’s GenSci

RTW Investments has helped launch and back Yarrow Bioscience, a US-based biotech focused on autoimmune thyroid diseases.1

Yarrow Bioscience and China’s Changchun GeneScience Pharmaceutical (GenSci) have entered a strategic partnership and exclusive license agreement for anti-TSHR antibody GS-098, which will be called YB-101 outside China.1

Under the deal, Yarrow receives exclusive global ex-China rights to develop, manufacture, and commercialize GS-098/YB-101 for Graves’ disease (GD) and thyroid eye disease (TED), while GenSci retains China rights.1

GenSci will receive a $70 million non‑refundable upfront payment, a $50 million near‑term development milestone, and additional development, regulatory and commercial milestone payments for a total potential deal value up to $1.365 billion, plus tiered double‑digit royalties on net sales in licensed territories.1

GS-098/YB-101 is a first‑in‑class anti‑thyroid stimulating hormone receptor (TSHR) monoclonal antibody designed to block pathogenic thyroid‑stimulating autoantibodies that drive GD and TED.1

The antibody works by selectively binding TSHR and preventing autoantibody‑induced receptor activation, thereby inhibiting the biological pathway responsible for hyperthyroidism and orbitopathy in these autoimmune conditions.1

The collaboration’s stated goal is to build a leading US-based biotech focused on underserved patients with autoimmune and endocrinology disorders, using this program as a cornerstone asset.1

RTW Investments describes the partnership with GenSci and the creation of Yarrow as part of its long‑term, company‑creation strategy in high‑impact immunology science.1

Sources:

1. https://www.businesswire.com/news/home/20251215486834/en/GenSci-and-RTW-Investments-Announce-Strategic-Partnership-on-Anti-TSHR-Antibody-GS-098-YB-101-for-Graves-Disease-and-Thyroid-Eye-Disease-With-Global-Ex-China-Development-Being-Led-by-Yarrow-Bioscience