Summit's partner Akeso reports positive Phase III data for ivonescimab in bile duct cancer

Summit Therapeutics disclosed in an August 25, 2026 8-K that its partner Akeso Inc. had released positive topline data from a Phase III trial testing ivonescimab in advanced biliary tract cancer. The disclosure covered the randomized Phase III HARMONi-GI1 study, known as AK112-309, which compared ivonescimab plus chemotherapy against durvalumab plus chemotherapy as a first-line treatment for patients with advanced biliary tract cancer.¹

The trial was run as a single-region, multi-center Phase III study in China, sponsored by Akeso, which alone generated, managed, and analyzed all the data.¹

On the results, Akeso said that at a pre-specified interim look, the ivonescimab arm showed a statistically significant improvement over the durvalumab arm on the trial's main measure, overall survival, which the company described as clinically meaningful.¹ The study also hit its secondary goals of progression-free survival and objective response rate.¹

Full data from this initial readout, including safety findings, are expected to be presented at a future medical meeting and published in a peer-reviewed journal.¹

The filing notes this is the first Phase III ivonescimab result outside of non-small cell lung cancer, adding to four prior positive NSCLC trial readouts. Summit holds license rights to ivonescimab, called SMT112 in its territories, across North and South America, Europe, the Middle East, Africa, and Japan, while the drug remains investigational and unapproved in Summit's license territories, including the United States and Europe.¹ Ivonescimab first won marketing approval in China in May 2024.¹