HARMONi-6, Featuring Ivonescimab Combined with Chemotherapy vs. Tislelizumab Plus Chemotherapy in 1L Treatment of Patients with Squamous NSCLC in China, to be Showcased in Presidential Symposium at ESMO 2025

Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") today announced that data from the Phase III HARMONi-6 trial, conducted in China and sponsored by our partner, Akeso, Inc. (HKEX Code: 9926.HK), featuring the novel, potential first-in-class investigational bispecific antibody, ivonescimab, will be featured as part of the Presidential Symposium at the European Society for Medical Oncology 2025 Congress (ESMO 2025) which takes place from October 17–21, 2025, in Berlin, Germany. The presentation will take place on Sunday, October 19 during the Presidential Symposium from 4:30pm – 6:30pm CET (10:30am – 12:30pm EDT).

HARMONi-6 is evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, a PD-1 inhibitor, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous non-small cell lung cancer (NSCLC) irrespective of PD-L1 expression. HARMONi-6 is a single region, multi-center, Phase III study conducted in China sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso.

On April 23, 2025, Akeso announced, via a press release, topline results from HARMONi-6. At a prespecified interim analysis conducted by an Independent Data Monitoring Committee, ivonescimab plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in PFS by blinded independent central radiology review committee (BICR) compared to tislelizumab plus chemotherapy. The PFS benefit was demonstrated in patients with either PD-L1-positive or PD-L1-negative tumors. Akeso noted that no new safety signals were identified in this Phase III study. Prior to HARMONi-6, there were no known Phase III clinical trials in NSCLC which have shown a statistically significant improvement compared to PD-(L)1 inhibitor therapy in combination with chemotherapy in a head-to-head setting.

The trial results will be presented by Dr. Shun Lu, MD, PhD, Chief of Shanghai Lung Cancer Center at Shanghai Chest Hospital, Professor of Medicine at Shanghai Jiaotong University, and associate editor for Journal of Thoracic Oncology, Lung Cancer, and editor for The Oncologist.

Summit is currently enrolling patients in the HARMONi-3 study. HARMONi-3 is a multiregional Phase III clinical trial sponsored by Summit which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab, an anti-PD-1 antibody, combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC. HARMONi-3 is currently enrolling patients globally and is conducted with registrational intent for the United States and other regions within Summit’s license territories.