Ivonescimab Data Sets across Multiple Tumor Types to Be Featured at ESMO 2026

Highlights Include Phase II Data Supporting Clinical Development Expansion for Ivonescimab

Summit Therapeutics Inc. (NASDAQ: SMMT) today announced that ivonescimab data will be featured in numerous presentations at the European Society for Medical Oncology 2026 Congress (ESMO 2026), taking place October 23-27, 2026, in Madrid, Spain.

Across 10 presentations at ESMO 2026, ivonescimab data will span a broad range of tumor types, led by positive overall survival findings from Akeso Inc.’s Phase III HARMONi-GI1 study of ivonescimab plus chemotherapy compared to durvalumab plus chemotherapy in first-line advanced biliary tract cancer, which is selected as a Late-Breaking Abstract for the Presidential Symposium. HARMONi-GI1 is a multi-center, Phase III study conducted in China and sponsored by Akeso, with all relevant data exclusively generated, managed, and analyzed by Akeso. On October 21, Summit and ECOG-ACRIN Cancer Research Group announced the initiation of the open-label Phase II/III EA2251 study, which plans to enroll patients in the U.S. who will be randomized to receive ivonescimab in combination with gemcitabine and cisplatin, or pembrolizumab or durvalumab in combination with gemcitabine and cisplatin as the established standard-of-care comparator regimen. Activation of clinical trial sites is expected to begin in the fourth quarter of 2026.

Additional data include findings from investigator-sponsored trials (ISTs). A rapid oral presentation and a proffered paper will feature ivonescimab-based regimens in first-line recurrent/metastatic thymic carcinoma and advanced renal cell carcinoma, respectively. The program also highlights emerging endometrial cancer (EC) data, alongside continued development in gastrointestinal cancers such as esophageal, gastric/GEJ, and pancreatic cancers; glioblastoma; and head and neck squamous cell carcinoma.

In a Phase II study in EC conducted at Memorial Sloan Kettering Cancer Center in New York, NY, ivonescimab monotherapy met the study’s primary endpoint for objective response rate with a manageable safety profile without new safety signals in previously treated patients with second-line and later EC. The strength of these results supported expansion of the IST led by Drs. Maria Rubinstein, MD, and Vicky Makker, MD, and provided a meaningful signal to inform opportunities for further development of ivonescimab in EC.

“The breadth of the ivonescimab data at ESMO underscores the expanding body of clinical evidence across a diverse range of tumor types and treatment settings,” said Dr. Maky Zanganeh, President and Co-Chief Executive Officer of Summit Therapeutics. “Our ambition for ivonescimab extends beyond any single indication. We are focused on advancing a rigorous clinical development program to determine where this novel IO bispecific antibody could make a meaningful difference for patients. We look forward to engaging with the global oncology community on these data at ESMO 2026.”

The ESMO 2026 ivonescimab presentations are listed below by tumor type:

Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit’s license territories, including the United States and Europe. Ivonescimab was initially approved for marketing authorization in China in May 2024.

About Ivonescimab

Ivonescimab, known as SMT112 in Summit’s license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 outside of Summit’s license territories, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. By design, ivonescimab displays unique cooperative binding to each of its intended targets with multifold higher affinity to PD-1 when in the presence of VEGF.

This design is intended to differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Summit believes ivonescimab’s specifically engineered tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, iScience, 2025). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of ivonescimab’s design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, iScience, 2025) increasing to approximately 10 days at steady state dosing, is to improve upon previously established efficacy thresholds, side effects, and safety profiles associated with prior approved drugs to these targets.

Ivonescimab was invented by Akeso Inc. (HKEX Code: 9926.HK) and is currently utilized in multiple Phase III clinical trials. Over 5,000 patients have been treated with ivonescimab in clinical studies globally and over 100,000 patients when considering those treated in a commercial setting in China, as noted by Akeso.

There are currently 17 Phase III clinical studies that are either announced, ongoing, or have been completed studying ivonescimab, five of which are Summit-sponsored global studies, two of which are studies sponsored by cooperative groups, and 10 of which are being or have been conducted in China by Akeso. Summit began its clinical development of ivonescimab in NSCLC and expanded its sponsored Phase III clinical development program into colorectal cancer (CRC) and urothelial carcinoma (bladder cancer).

About Summit Therapeutics Inc.

Summit Therapeutics Inc. is a biopharmaceutical oncology company focused on the discovery, development, and commercialization of patient-, physician-, caregiver- and societal-friendly medicinal therapies intended to improve quality of life, increase potential duration of life, and resolve serious unmet medical needs.

Summit was founded in 2003 and the company’s shares are listed on the Nasdaq Global Market (symbol "SMMT"). Summit is headquartered in Miami, Florida, with additional offices in Palo Alto, California, Princeton, New Jersey, Dublin, Ireland, and Oxford, UK.

For more information, please visit https://www.smmttx.com and follow Summit on X @SMMT_TX.

Summit Forward-Looking Statements

Any statements in this press release about the Company’s future expectations, plans and prospects, including but not limited to, statements about the risk that the private placement does not close on the anticipated timeline or at all, including because required regulatory clearances are not obtained or other closing conditions are not satisfied, dilution to existing stockholders, and potential adverse effects on the market price of the Company's common stock, including from future sales by AstraZeneca, the Company’s broad discretion over the use of proceeds, and the possibility that the proceeds will not be sufficient to fund operations as long as anticipated, AstraZeneca’s ownership and contractual rights, including Third Party acquisition participation, and registration rights, and potential conflicts of interest, the completion of the Private Placement does not depend on the parties entering into a definitive collaboration agreement, the Company's reliance on AstraZeneca for the supply of AstraZeneca’s products and other contributions to the clinical trials, the clinical and preclinical development of the Company’s product candidates, entry into and actions related to the Company’s partnership with Akeso Inc. and other collaborations, the intended use of the net proceeds from the private placements, the Company's anticipated spending and cash runway, the therapeutic potential of the Company’s product candidates, the potential commercialization of the Company’s product candidates, the timing of initiation, completion and availability of data from clinical trials, the potential submission of applications for marketing approvals, the expected timing of BLA submissions or FDA decisions, potential acquisitions, statements about the previously disclosed At-The-Market equity offering program (“ATM Program”), the expected proceeds and uses thereof, the Company’s estimates regarding stock-based compensation, and other statements containing the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "target," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the Company’s ability to sell shares of our common stock under the ATM Program, the conditions affecting the capital markets, general economic, industry, or political conditions, including the effects of geopolitical developments, domestic and foreign trade policies, and monetary policies, the results of our evaluation of the underlying data in connection with the development and commercialization activities for ivonescimab, the outcome of discussions with regulatory authorities, including the Food and Drug Administration, the uncertainties inherent in the initiation of future clinical trials, availability and timing of data from ongoing and future clinical trials, the results of such trials, and their success, global public health crises, that may affect timing and status of our clinical trials and operations, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials or preclinical studies will be indicative of the results of later clinical trials, whether business development opportunities to expand the Company’s pipeline of drug candidates, including without limitation, through potential acquisitions of, and/or collaborations with, other entities occur, expectations for regulatory approvals, laws and regulations affecting government contracts and funding awards, availability of funding sufficient for the Company’s foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in the "Risk Factors" and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of filings that the Company makes with the Securities and Exchange Commission. Summit defines a “positive study” as a clinical study with one or more prespecified primary endpoints in which one of those endpoints achieves a statistically significant benefit according to the protocol or statistical analysis plan. Any change to our ongoing trials could cause delays, affect our future expenses, and add uncertainty to our commercialization efforts, as well as to affect the likelihood of the successful completion of clinical development of ivonescimab. Accordingly, readers should not place undue reliance on forward-looking statements or information. In addition, any forward-looking statements included in this press release represent the Company’s views only as of the date of this release and should not be relied upon as representing the Company’s views as of any subsequent date. The Company specifically disclaims any obligation to update any forward-looking statements included in this press release.

Summit Therapeutics and the Summit Therapeutics logo are registered trademarks of Summit Therapeutics Inc. and/or its affiliates. Copyright 2026, Summit Therapeutics Inc. All Rights Reserved.

View source version on businesswire.com: https://www.businesswire.com/news/home/20261022076516/en/