Summit Therapeutics Ivonescimab Combo Extends Progression-Free Survival in Lung Cancer Patients

Summit Therapeutics Inc. announced that The Lancet Oncology published primary analysis results from its global Phase III HARMONi trial.

Significant Progression-Free Survival Improvement

The study evaluated ivonescimab combined with platinum-based doublet chemotherapy versus placebo plus chemotherapy.

The regimen targeted patients with EGFR-mutant, locally advanced or metastatic non-squamous non-small cell lung cancer who had disease progression after third-generation EGFR tyrosine kinase inhibitor therapy.

Trial data showed patients receiving the ivonescimab combination achieved a median progression-free survival of 6.8 months, compared with 4.4 months in the placebo group.

This represented a statistically significant improvement with a hazard ratio of 0.52. Independent radiology reviewers confirmed these findings, noting consistent benefit across prespecified subgroups.

Manageable Safety Profile and Survival Trends

While the primary overall survival analysis showed a positive trend for the ivonescimab combination, it did not reach statistical significance at that time.

Researchers observed a manageable safety profile, reporting a treatment-related serious bleeding event rate of less than 1%.

Following the primary data release, the company shared an updated OS analysis based on a June 2026 data cutoff.

This subsequent analysis showed a continued positive OS trend, with a hazard ratio of 0.76 in Western patients. Efficacy and safety profiles remained consistent across Asian and Western populations.

Upcoming Presentations and Regulatory Milestones

Summit Therapeutics will present further details from this updated data analysis at the 2026 World Conference on Lung Cancer, scheduled for September 15, 2026.

Meanwhile, the U.S. Food and Drug Administration has assigned an action date of November 14, 2026, for the company's biologics license application.

In August, Summit Therapeutics' partner Akeso Inc. noted China's approval of ivonescimab in combination with chemotherapy as a first-line treatment for patients with advanced squamous non-small cell lung cancer.

SMMT stock performance: As of Tuesday's release, Summit Therapeutics shares were up 4.05% at $13.24.