Miami-based Summit Therapeutics Inc. (Nasdaq: SMMT) reported updated overall survival data from its global Phase III HARMONi trial showing that the hazard ratio for ivonescimab (SMT112, AK112) plus chemotherapy versus placebo plus chemotherapy improved with longer follow-up, and that the benefit observed in Western patients has converged with results seen earlier in Asian patients.
The updated analysis adds to the evidence supporting Summit's Biologics License Application for ivonescimab in EGFR-mutated non-small cell lung cancer (NSCLC), which is under US FDA review with a Prescription Drug User Fee Act target action date of November 14, 2026.
The HARMONi trial enrolled patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who had progressed after treatment with a third-generation EGFR tyrosine kinase inhibitor such as osimertinib. Patients were randomized to ivonescimab plus platinum-doublet chemotherapy or placebo plus chemotherapy, with progression-free survival and overall survival as co-primary endpoints. The primary analysis, conducted in April 2025, met its progression-free survival endpoint with statistical significance; overall survival showed a favorable trend that did not reach significance at that time, with a hazard ratio of 0.79 (95% CI: 0.62–1.01; p=0.057) and median overall survival of 16.8 months for the ivonescimab arm versus 14.0 months for placebo plus chemotherapy.
With additional follow-up—driven largely by maturation of the Western subgroup—the overall survival hazard ratio improved: 0.78 (95% CI: 0.62–0.98; nominal p=0.0332) at a September 2025 cutoff, and 0.76 in the intention-to-treat population as of a June 2026 cutoff. In the Western subgroup specifically, the hazard ratio moved from 0.98 at a median follow-up of 9.2 months, to 0.84 at 13.7 months, to 0.76 at 23.2 months — now matching the hazard ratio observed in the overall intention-to-treat population. Median follow-up for Asian patients, whose follow-up matured earlier, stands at 32.7 months. Summit said no additional safety signals were observed in the latest data cut and that the safety profile remained consistent with prior Phase III readouts, though the company has not yet released updated median overall survival figures, confidence intervals, or safety tabulations for the June 2026 cutoff.