Summit Therapeutics reports updated Phase III HARMONi overall survival results showing an OS hazard ratio of 0.76 for ivonescimab plus chemotherapy in EGFR-mutated NSCLC, supporting consistent outcomes across global and western patients ahead of the FDA’s November 2026 PDUFA decision.
Written By: Anamika Koshti, PharmD
Reviewed By: Pharmacally Editorial Team
On July 22, 2026, Summit Therapeutics Inc. announced updated overall survival (OS) results from the global Phase III HARMONi trial (NCT06396065), evaluating investigational ivonescimab plus platinum-doublet chemotherapy versus placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who progressed after treatment with a third-generation EGFR tyrosine kinase inhibitor (TKI). The June 2026 descriptive analysis reported an OS hazard ratio (HR) of 0.76 in both the global intention-to-treat (ITT) population and the western patient subgroup, demonstrating consistent treatment effects across geographic regions after longer western patient follow-up. Complete efficacy data will be presented at an upcoming medical conference.
EGFR-Mutated NSCLC: The Clinical Context
EGFR mutations occur in approximately 10% to 15% of patients with non-squamous NSCLC in western populations and 40% to 50% of patients in Asia, making them among the most common actionable oncogenic drivers in this disease. Although third-generation EGFR TKIs such as osimertinib are standard treatment, most patients eventually experience disease progression, leaving limited therapeutic options.
How Ivonescimab Works
Ivonescimab (SMT112 in Summit’s licensed territories) is an investigational tetravalent bispecific antibody targeting PD-1 and VEGF. Its cooperative binding design provides multifold higher affinity for PD-1 in the presence of VEGF, which is preferentially expressed within the tumor microenvironment, with the aim of concentrating activity at tumor sites. Engineered by Akeso Inc., ivonescimab received its first marketing approval in China in May 2024 but remains investigational in Summit’s licensed territories, including the United States and Europe.
HARMONi Trial Design
HARMONi is a global, randomized, double-blind, placebo-controlled, multicenter Phase III trial that enrolled 438 patients (219 per arm), including 83 western patients in the ivonescimab group and 82 in the placebo group. The study compares ivonescimab plus platinum-doublet chemotherapy with placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC following progression on a third-generation EGFR TKI. The trial has two co-primary endpoints: progression-free survival (PFS), which met statistical significance in the primary analysis, and overall survival.
Three Sequential Overall Survival Analyses
April 2025 Data Cut-Off (Primary OS Analysis): The primary OS analysis showed a favorable trend for ivonescimab plus chemotherapy but did not achieve statistical significance. The global ITT population demonstrated an OS HR of 0.79 (95% CI: 0.62-1.01; p=0.057), with a median OS of 16.8 months versus 14.0 months for placebo plus chemotherapy. Western patients had a median follow-up of only 9.2 months, shorter than the median OS in both treatment arms, resulting in an immature subgroup analysis with an HR of 0.98.
September 2025 Data Cut-Off: With western patient follow-up extended to 13.7 months, while Asian patient data remained locked at a median follow-up of 32.7 months, the global ITT OS HR improved to 0.78 (95% CI: 0.62-0.98; nominal p=0.0332). The western subgroup HR improved to 0.84, while median OS remained unchanged from the primary analysis in both treatment arms.
June 2026 Data Cut-Off (Current Analysis): The latest descriptive analysis extended western patient follow-up to 23.2 months, with most patients having completed two years of treatment or discontinued therapy. Asian patient data remained locked at the September 2025 analysis with a median follow-up of 32.7 months. The OS HR reached 0.76 in both the global ITT population and the western subgroup, demonstrating geographic consistency after longer western follow-up. Complete efficacy results, including confidence intervals, median OS, and additional statistical analyses, are expected at an upcoming medical conference.
Safety
The June 2026 analysis showed that ivonescimab maintained an acceptable and manageable safety profile consistent with previous Phase III HARMONi findings. No additional safety signals were identified.
Regulatory Status
Summit’s Biologics License Application (BLA), supported by the HARMONi trial, was accepted for filing by the U.S. Food and Drug Administration (FDA) in January 2026. The application has a Prescription Drug User Fee Act (PDUFA) target action date of November 14, 2026. Summit also confirmed that the updated June 2026 OS analysis has been made available to the FDA as part of the ongoing review.
What These Findings Mean
The evolving HARMONi OS analyses illustrate how longer follow-up improved the maturity of survival data in western patients. While the western subgroup HR was 0.98 at the primary analysis with only 9.2 months of follow-up, it improved to 0.76 after follow-up reached 23.2 months, matching the global ITT result and supporting consistent treatment effects across geographic regions. Although the updated analysis continues to show a favorable OS trend, the June 2026 findings remain descriptive, and complete efficacy data will be presented at an upcoming medical conference while the FDA continues its BLA review ahead of the November 14, 2026 PDUFA target action date.
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About the Writer
Anamika Koshti (LinkedIn) is a PharmD professional and healthcare writer with interests in clinical research, pharmacovigilance, and evidence-based medicine. She has authored peer-reviewed publications on Alzheimer’s disease and PCOS, presented research at national conferences, and gained hands-on experience in medical content development and clinical data interpretation. She is committed to translating complex medical research into accurate, accessible content for healthcare professionals and patients.