China-based Zelgen Biopharm has opened the first Phase III study of nilvanstomig, a wholly owned, humanised PD-1×TIGIT bispecific antibody (BsAb), making it the first domestically developed PD-1×TIGIT asset to reach Phase III globally alongside AstraZeneca's rilvegostomig among eight clinical-stage PD-(L)1×TIGIT bispecifics. The 600-patient, open-label trial tests nilvanstomig 20 mg/kg every three weeks plus bevacizumab (Avastin) against sintilimab plus a bevacizumab biosimilar as first-line therapy in advanced hepatocellular carcinoma (HCC), with progression-free survival (PFS) and overall survival as co-primary endpoints.

The Phase II signal underpinning the move was strong: at a roughly nine-month median follow-up, nilvanstomig 20 mg/kg plus bevacizumab cut progression or death risk by 65% versus the sintilimab combo (HR 0.35), delivered median PFS of 11.2 months versus 6.7 months for control, and lifted mRECIST ORR to 61.3% from 40.6%, with manageable Grade 1 to 2 toxicity and no unexpected immune-related adverse events.