In a head-to-head Phase 3 study, ivonescimab plus chemotherapy improved overall survival versus durvalumab plus chemotherapy in advanced biliary tract cancer, with median OS of 14.9 months vs 12.1 months and a one-sided P value of .0031, while 12- and 18-month OS rates favored ivonescimab (59.7% vs 50.7%, and 44.0% vs 32.5%).

This milestone marks the first known Phase 3 to show an OS advantage for an immunotherapy–chemotherapy combo over an active immunotherapy regimen in advanced biliary tract cancer, as prior trials compared against chemotherapy alone.

The trial randomised patients to ivonescimab 20 mg/kg or durvalumab 1500 mg every three weeks, each paired with gemcitabine and cisplatin for up to eight cycles followed by maintenance, with overall survival as the primary endpoint and progression-free survival and objective response rate as key secondary endpoints.

Experts urge cautious interpretation of China-only results due to potential differences in patient populations and practice patterns, and emphasize the need to review full safety data, including VEGF-inhibition–related risks like bleeding and hypertension.

regulatory timing notes indicate an FDA action target on a separate lung-cancer application, while the biliary-cancer U.S. trial activation is planned for the fourth quarter of 2026.

Summit reported about $690.7 million in cash and investments as of mid-2026, with U.S. site activations for the biliary-trial planned in Q4 2026 and potential follow-on trials against pembrolizumab or durvalumab in the U.S. setting.

Ivonescimab is a PD-1/VEGF bispecific antibody, approved in China for lung cancer since 2024 but not yet approved in the United States; Summit Therapeutics holds rights in several regions.

The article notes the potential for targeted therapies in biliary tract cancers (e.g., FGFR2, IDH1) and encourages checking for clinical trials and site participation, such as EA2251.

The trial enrolled 682 patients, and main survival benefit data were not disclosed in advance; OS results were announced at the conference on October 25.

A U.S. Phase 2/3 trial of ivonescimab plus chemotherapy is planned to activate sites in Q4 2026 under a collaboration with ECOG-ACRIN, with OS as the primary endpoint in first-line biliary tract cancer.

EA2251 in the United States compares ivonescimab plus chemotherapy against pembrolizumab or durvalumab plus chemotherapy, with OS as the primary endpoint and site activations anticipated in Q4 2026.

Summit’s U.S. trials will await broader data before regulatory decisions, as the program continues to evaluate ivonescimab in first-line BTC.