Biopharmaceutical oncology company Summit Therapeutics Inc (NASDAQ:SMMT) said on Wednesday that it has partnered with the ECOG-ACRIN Cancer Research Group to evaluate ivonescimab in a registration-enabling Phase II/III clinical trial for first-line treatment of advanced biliary tract cancer.

The open-label EA2251 study will compare ivonescimab combined with gemcitabine and cisplatin against pembrolizumab or durvalumab with the same chemotherapy regimen, with overall survival as the primary endpoint.

The trial is planned to enrol patients in the United States, with clinical site activations expected to begin in the fourth quarter of 2026.

EA2251 is the second Phase III study of ivonescimab in biliary tract cancer, following Akeso's HARMONi-GI1 trial, which reported statistically significant and clinically meaningful overall survival superiority over a durvalumab-based regimen at a prespecified interim analysis in August 2026.

Detailed HARMONi-GI1 results are scheduled for presentation at the European Society for Medical Oncology 2026 Congress on 25 October.