Shares of Summit Therapeutics SMMT rose 6.5% on Wednesday after the company’s partner Akeso announced positive top-line results from the phase III HARMONi-GI1 study conducted in China in certain patients with biliary tract cancer (BTC).
The study evaluated ivonescimab plus chemotherapy versus AstraZeneca AZN’s blockbuster cancer drug Imfinzi (durvalumab) plus chemotherapy as a first-line treatment in patients with advanced BTC, a rare group of cancers affecting the bile ducts and gallbladder. Imfinzi, a PD-L1 monoclonal antibody, holds approvals across multiple cancer indications and is a key revenue driver for AZN.
At a pre-specified interim analysis, the ivonescimab-based regimen achieved statistically significant and clinically meaningful superiority over the durvalumab-based regimen on the primary endpoint of overall survival (OS). The study also met the key secondary endpoints of progression-free survival and objective response rate.
While Akeso did not provide any data supporting these numbers, it expects to report detailed results from the study at a future medical meeting and publish them in a peer-reviewed journal.
Summit is developing ivonescimab in collaboration with Akeso. The company acquired an exclusive license from Akeso in 2022 to develop and market the drug in the United States, Canada, Europe and Japan. Summit later amended this collaboration agreement in June 2024, expanding its licensing deal to cover Latin America (including Mexico and all countries in Central America, South America and the Caribbean), the Middle East and Africa. Akeso retains the rights to market the drug in China, where the drug is approved for three non-small cell lung cancer (NSCLC) indications.
Year to date, shares of SMMT have declined 18.6% against the industry’s 3.2% growth.
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A Key Validation Beyond NSCLC
The HARMONi-GI1 results represent an important milestone for ivonescimab because they provide the first phase III evidence of the drug delivering an OS benefit over an established anti-PD-(L)1-based regimen plus chemotherapy in advanced BTC.
The positive outcome therefore strengthens the broader development case for the drug and raises expectations to extend well beyond its initial NSCLC focus.
SMMT’s Progress With Ivonescimab
Summit is pursuing a broad global development program for ivonescimab.
In May 2025, the company announced positive phase III HARMONi data evaluating ivonescimab plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who had progressed following EGFR-TKI treatment. Based on these results, Summit submitted a biologics license application to the FDA in January 2026, with a regulatory decision expected by Nov. 14, 2026.
Summit is currently advancing ivonescimab in several late-stage programs. In NSCLC, the company is evaluating the candidate in the HARMONi-3 and HARMONi-7 phase III studies. Beyond lung cancer, the HARMONi-GI3 study is evaluating ivonescimab plus chemotherapy against bevacizumab plus chemotherapy as first-line treatment for patients with unresectable metastatic colorectal cancer (CRC). This represents Summit’s first study outside NSCLC.
Earlier this month, the company initiated the global phase II/III HARMONi-GU1 study in genitourinary cancer. The study is evaluating ivonescimab plus enfortumab vedotin (EV) against Merck’s MRK Keytruda (pembrolizumab) plus EV as first-line treatment for patients with advanced urothelial or bladder cancer.
Our Take on the Results
While Summit’s near-term value proposition remains closely tied to ivonescimab’s development in NSCLC, the successful HARMONi-GI1 outcome suggests that the drug could have meaningful potential across multiple cancer indications. Positive results in BTC, alongside ongoing programs in CRC and genitourinary cancer, could expand the drug’s addressable market substantially if subsequent studies confirm these benefits.
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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This article originally published on Zacks Investment Research (zacks.com).