Ivonescimab, Akeso’s PD-1 by VEGF bispecific antibody partnered with Summit Therapeutics outside China, plus gemcitabine and cisplatin chemotherapy cut the risk of death by 25 percent against durvalumab (AstraZeneca’s Imfinzi) plus the same chemotherapy as first-line treatment for advanced biliary tract cancer, in the Phase 3 HARMONi-GI1 trial presented at ESMO on October 25. Median overall survival was 14.9 months on ivonescimab against 12.1 months on the Imfinzi regimen (hazard ratio 0.75, 95 percent confidence interval 0.61 to 0.92, one-sided p=0.0031) at a median follow-up of 14.3 months. Median progression-free survival was 8.4 months against 5.8 months (hazard ratio 0.61), and the response rate was 53.8 percent against 32.5 percent. The trial randomised 682 patients, 340 to ivonescimab and 342 to durvalumab.
The comparison is the point. Imfinzi plus chemotherapy is the current first-line standard in biliary tract cancer, itself established on a survival advantage of about 20 percent over chemotherapy alone, as Fierce Pharma noted. Beating that active standard, rather than chemotherapy, is a harder test, and presenter Jian Zhou of Zhongshan Hospital in Shanghai said the results support ivonescimab plus chemotherapy as a potential new first-line standard. The survival benefit held even though more control-arm patients went on to later treatment, 45.9 percent against 31.8 percent, and grade 3 or higher immune-related adverse events were 4.1 percent in each arm, with no new safety signals reported.
Two limits frame the result. The absolute survival gain is 2.8 months in a cancer where progress is measured in small increments, and the trial is an interim analysis run entirely in China by Akeso. Summit, which holds rights in North America, Europe and Japan, has a separate registration-enabling United States trial in this setting expected to start activating sites in the fourth quarter of 2026, so Western approval does not follow automatically from HARMONi-GI1.
Commercially, the win widens the contest around the bispecific class. Akeso chief executive Michelle Xia told Fierce Pharma she expects more combination opportunities for ivonescimab after its first Phase 3 success beyond lung cancer, and Fierce reported that AstraZeneca, whose drug was the losing comparator here, has separately taken a strategic equity stake in and clinical collaboration with Summit. The class is no longer a lung cancer story alone.