Berlin, Germany — October 19, 2025 — Leads & Copy — Summit Therapeutics Inc. (NASDAQ: SMMT) announced positive results from the Phase III HARMONi-6 trial of ivonescimab in advanced squamous non-small cell lung cancer (NSCLC). The trial, conducted in China by partner Akeso, Inc., showed ivonescimab plus chemotherapy significantly improved progression-free survival (PFS) compared to tislelizumab plus chemotherapy.
The HARMONi-6 study evaluated ivonescimab combined with platinum-based chemotherapy against tislelizumab, a PD-1 inhibitor, also with chemotherapy, in patients with locally advanced or metastatic squamous NSCLC, regardless of PD-L1 expression. The results were presented at the European Society for Medical Oncology 2025 Congress (ESMO 2025) in Berlin.
The trial demonstrated a statistically significant improvement in PFS with ivonescimab, achieving a hazard ratio of 0.60 (95% CI: 0.46, 0.78; p<0.0001). This benefit was observed across clinical subgroups, including those with PD-L1 negative or positive expression. The overall response rate (ORR) and duration of response (DoR) were also higher in patients treated with ivonescimab plus chemotherapy.
Ivonescimab demonstrated a manageable safety profile, consistent with previous Phase III studies. The Lancet published the HARMONi-6 results in a manuscript titled, “Ivonescimab plus chemotherapy versus tislelizumab plus chemotherapy as first-line treatment for advanced squamous non-small-cell lung cancer (HARMONi-6): a randomised, double-blind, phase 3 trial.”
Summit is enrolling patients in the HARMONi-3 study, a multiregional Phase III trial evaluating ivonescimab plus chemotherapy versus pembrolizumab plus chemotherapy in first-line metastatic NSCLC. The company expects to complete enrollment in the squamous cohort in the first half of 2026 and reach the prespecified number of events for PFS analysis in the second half of 2026.
Dr. Maky Zanganeh, Co-Chief Executive Officer and President of Summit, highlighted ivonescimab’s potential for improved clinical outcomes and longer therapy duration. Robert W. Duggan, Chairman and Co-Chief Executive Officer of Summit, expressed pride in the partnership with Akeso and their advancements in ivonescimab development.
Contact:
Maky Zanganeh
Co-Chief Executive Officer and President, Summit Therapeutics Inc.
Source: Summit Therapeutics Inc.
