Summit Therapeutics Inc. Announces Partner's Positive Phase III Trial Results

What Happened

• On August 25, 2026, Summit Therapeutics (SMMT) disclosed via Form 8-K that partner Akeso, Inc. announced positive topline results from the randomized Phase III HARMONi-GI1 study in China.
• At a pre-specified interim analysis, the ivonescimab-plus-chemotherapy regimen met the primary endpoint, showing statistically significant and clinically meaningful superiority in overall survival versus durvalumab-plus-chemotherapy. The study also met key secondary endpoints: progression-free survival (PFS) and objective response rate (ORR).
• HARMONi-GI1 is a single-region, multi-center, Phase III trial sponsored, conducted, and analyzed solely by Akeso. Detailed safety and efficacy data will be presented at an upcoming medical congress and submitted for peer-reviewed publication. A press release dated August 25, 2026 is attached to the 8-K as Exhibit 99.1.

Key Details

• Date of announcement: August 25, 2026; 8-K filed by Summit on August 26, 2026.
• Trial: HARMONi-GI1, randomized Phase III in advanced biliary tract cancer (first-line setting).
• Treatment comparison: ivonescimab + chemotherapy vs durvalumab + chemotherapy.
• Endpoints met at interim analysis: primary — overall survival (statistically significant, clinically meaningful); key secondaries — PFS and ORR.
• All trial data and analysis were generated and managed by Akeso (sponsor); full data pending congress presentation and journal publication.

Why It Matters

• For investors, this is a material clinical milestone for Summit’s partnered asset, ivonescimab: a positive Phase III readout on overall survival is a critical proof point for regulatory and commercial potential in biliary tract cancer.
• Because Akeso sponsored and controlled the study and data, Summit’s public disclosure is informational; further details, timing of regulatory steps, and any partnership-related milestones or payments have not been disclosed in this 8-K.
• Watch for the forthcoming congress presentation, peer‑reviewed publication, and any future updates from Akeso or Summit that clarify detailed results, safety profile, regulatory plans, or financial impacts.