China-based Alphamab Oncology has announced that its subsidiary Jiangsu Alphamab granted Pathos AI exclusive ex-Greater China rights to JSKN016, a first-in-class TROP2×HER3 bispecific antibody–drug conjugate (ADC) built on the company's single-domain antibody and glycan-site-specific conjugation platforms with a homogeneous DAR4 payload of a topoisomerase I inhibitor. JSKN016 is already in multiple Phase II studies across lung and breast cancers, with a Phase III trial underway in triple-negative breast cancer (TNBC), and is designed to block oncogenic signalling while delivering targeted cytotoxic release with reduced off-target toxicity.

The transaction carries USD 125 million upfront, up to USD 2.093 billion in aggregate development and commercial milestones, and high-single to low-double-digit percentage royalties on ex-China net sales, with Pathos bearing all development and commercialisation costs. Alphamab retains full rights in Mainland China, Hong Kong, Macau, and Taiwan, and receives a warrant to subscribe for USD 62.5 million of Pathos preferred shares at its discretion.

The deal extends Alphamab's ADC out-licensing track record and positions JSKN016 as a differentiated dual-target entrant against single-target TROP2 assets such as datopotamab deruxtecan.