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Summit Expands Ivonescimab Development Into Biliary Tract Cancer

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Key Takeaways

  • Summit is testing ivonescimab plus chemotherapy as a first-line treatment for advanced biliary tract cancer.
  • The phase II/III EA2251 study will compare overall survival against Keytruda and Imfinzi plus chemotherapy.
  • The HARMONi-GI1 study showed significant survival benefit for ivonescimab plus chemotherapy versus Imfinzi.

Summit Therapeutics (SMMT - Free Report) is expanding the clinical development of its lead investigational drug, ivonescimab, beyond lung cancer into biliary tract cancer (BTC), a rare and aggressive group of gastrointestinal cancers. The company has announced a clinical trial collaboration with the ECOG-ACRIN Cancer Research Group to evaluate ivonescimab in combination with chemotherapy as a first-line treatment for patients with advanced BTC in the United States.

The registration-enabling phase II/III EA2251 study will compare ivonescimab plus chemotherapy with two established treatment regimens: Merck’s (MRK - Free Report) Keytruda (pembrolizumab) plus chemotherapy and AstraZeneca’s (AZN - Free Report) Imfinzi (durvalumab) plus chemotherapy. The open-label study will randomly assign participants to one of these three treatment groups. Overall survival (OS), which measures how long patients live after treatment begins, will be the study’s primary endpoint.

Merck’s Keytruda and AstraZeneca’s Imfinzi are FDA-approved immunotherapies for multiple cancers, including lung cancer and BTC, with additional indications varying by drug.

Through this study, Summit aims to determine whether ivonescimab combined with chemotherapy can improve survival in first-line BTC patients compared with existing immunotherapy-based treatments. Clinical trial site activation is expected to begin in the fourth quarter of 2026.

Year to date, shares of SMMT have declined 9.5% compared with the industry’s 2.2% fall.

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The EA2251 study marks the second phase III study evaluating ivonescimab in BTC, following HARMONi-GI1, sponsored by Summit’s Chinese partner, Akeso. In August 2026, the HARMONi-GI1 study met its primary endpoint at a prespecified interim analysis. Ivonescimab combined with chemotherapy demonstrated a statistically significant and clinically meaningful OS benefit compared with AstraZeneca’s Imfinzi plus chemotherapy in patients receiving first-line treatment for BTC.

Detailed results from the HARMONi-GI1 study are scheduled to be presented at a medical conference later this week. These findings could provide further insight into ivonescimab’s potential as a treatment for advanced BTC.

Summit Expands Ivonescimab Into Other Cancers

Summit’s study in BTC represents another step in the company’s efforts to expand ivonescimab beyond lung cancer into additional tumor types with significant unmet medical needs.

Summit is expanding ivonescimab beyond lung cancer into other solid tumors, including biliary tract, colorectal, bladder, breast and kidney cancer. Its phase III HARMONi-GI3 study is testing ivonescimab plus chemotherapy in metastatic colorectal cancer, while HARMONi-GU1 is evaluating it with Pfizer’s/Astellas’ Padcev in advanced bladder cancer. Partnerships with AstraZeneca, Daiichi Sankyo, Arcus Biosciences and GSK will further advance the drug’s evaluation across different cancer types.

Meanwhile, Summit continues to prioritize lung cancer as its most immediate path to U.S. commercialization. The FDA is reviewing ivonescimab plus chemotherapy for patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who had progressed following EGFR-TKI treatment, with a decision expected by Nov. 14, 2026.

SMMT’s Zacks Rank 

Summit currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 (Strong Buy) Rank stocks here.

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