China-based Harbour BioMed has entered into a licensing and equity partnership with the newly formed Solstice Oncology for its clinical-stage CTLA-4 monoclonal antibody (mAb), porustobart, outside of Greater China. Under the agreement, Harbour will receive an upfront and near-term package valued at over USD 105 million, comprising USD 50 million in cash, a USD 5 million near-term payment, and equity in Solstice Oncology valued at over USD 50 million. Harbour is also eligible for up to approximately USD 1.1 billion in future development, regulatory and commercial milestone payments, plus tiered royalties on ex-Greater China net sales.

Porustobart is a next-generation, fully human heavy-chain-only anti-CTLA-4 mAb developed from Harbour's proprietary HCAb platform. It is designed to have enhanced antibody-dependent cellular cytotoxicity (ADCC) activity for selective depletion of intratumoural regulatory T-cells (Treg), potentially offering an improved safety profile and efficacy over traditional CTLA-4 inhibitors.

According to PharmCube's NextBiopharm® database, this represents China's second-largest out-licensing deal in the CTLA-4 space. Click here to request a free trial for NextBiopharm®.