In addition to targeting the B7-H4 surface antigen, which is overexpressed in ovarian and endometrial cancers and is often associated with poor prognosis, HS-20089 utilises clinically validated ADC technologies such as a topoisomerase inhibitor (TOPOi) payload.1 TOPOi is a validated mechanism of action in approved anti-cancer medicines and a proven standard of care in the treatment of breast and ovarian cancers.

This agreement builds on GSK’s strategic R&D focus on tumour-cell targeting modalities as well as expertise in gynaecologic cancers including a significant medical and commercial presence. HS-20089 complements GSK’s oncology portfolio and strategic disease area focus, including potential future combinations. GSK plans to begin phase I trials outside of China in 2024.

Under the terms of this agreement, GSK will pay an $85 million upfront payment. In addition, Hansoh will be eligible to receive up to $1.485 billion in success-based milestones for HS-20089. Upon commercialisation of HS-20089, GSK will also pay tiered royalties on global net sales outside of China’s mainland, Hong Kong, Macau, and Taiwan.