Summit Therapeutics Reports Positive Phase III BTC Results

Miami, Florida, Aug 25, 2026

Ivonescimab Shows Overall Survival Benefit in BTC

At a prespecified interim analysis, the ivonescimab-based treatment regimen met the primary endpoint of overall survival, demonstrating statistically significant and clinically meaningful superiority compared with the durvalumab-based regimen. The study also met key secondary endpoints evaluating progression-free survival (PFS) and objective response rate (ORR). Detailed efficacy and safety findings from the HARMONi-GI1 readout are expected to be presented at a future medical congress and published in a peer-reviewed journal, meaning the currently available information remains topline and does not yet provide the complete numerical dataset. The HARMONi-GI1 study was conducted exclusively in China, where ivonescimab is approved and commercially available for certain NSCLC indications. Importantly, the treatment remains investigational in Summit Therapeutics’ licensed territories, including the United States and Europe. The positive BTC findings therefore represent a clinical development milestone rather than a regulatory approval for biliary tract cancer.

Bispecific Design Combines PD-1 and VEGF Targeting

Ivonescimab, known as SMT112 in Summit’s licensed territories and AK112 outside those territories, is an investigational bispecific antibody designed to combine PD-1 immune checkpoint blockade with VEGF anti-angiogenic activity in a single molecule. According to the source, the antibody has a tetravalent structure with four binding sites and is engineered to demonstrate cooperative binding characteristics involving PD-1 and VEGF. The development strategy is intended to concentrate activity within the tumor microenvironment, where both targets may be more highly expressed than in normal tissue. Akeso has advanced ivonescimab through a broad clinical development program, with the source reporting that more than 4,000 patients have received ivonescimab in clinical studies globally. The program currently includes numerous Phase III studies spanning several cancer types. In addition to BTC, ongoing or completed development programs include NSCLC, colorectal cancer, urothelial carcinoma, head and neck cancer, triple-negative breast cancer, small cell lung cancer and pancreatic cancer.

HARMONi-GI1 Expands Ivonescimab Oncology Program

The positive HARMONi-GI1 readout adds advanced biliary tract cancer to the growing list of indications in which ivonescimab is being evaluated. Summit highlighted that five Phase III ivonescimab studies have reported positive results to date, including four in NSCLC and the latest study in BTC. Earlier studies conducted by Akeso in China, including HARMONi-A, HARMONi-2 and HARMONi-6, have also generated positive Phase III results, while Summit’s global HARMONi study has supported continued development in NSCLC. Summit is also advancing global studies designed to evaluate ivonescimab across additional cancer settings. These include HARMONi-GI3 in metastatic colorectal cancer and HARMONi-GU1 in urothelial carcinoma, alongside multiple NSCLC programs. The company previously submitted a Biologics License Application for ivonescimab in an NSCLC setting, with the FDA accepting the application for filing in January 2026 and a PDUFA target date of November 14, 2026. The HARMONi-GI1 findings strengthen the development case for a dual-targeted immuno-oncology approach combining checkpoint inhibition and angiogenesis blockade. However, the study was conducted in a single region, and complete efficacy and safety data have not yet been publicly presented. Further peer-reviewed data and regulatory evaluation will be important in determining the broader clinical and commercial potential of ivonescimab in biliary tract cancer and other solid tumors.

Source: Summit Therapeutics, Akeso press relese