Summit Therapeutics Inc. (Nasdaq: SMMT) announced that updated overall survival (OS) results from the global Phase III HARMONi clinical trial were presented at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer (WCLC 2026) in Seoul on September 15, 2026. The filing details data regarding ivonescimab, a potential first-in-class bispecific antibody, in combination with chemotherapy for patients with EGFR-mutated non-small cell lung cancer (NSCLC).
According to the filing, the updated analysis, conducted with a data cut-off date in June 2026, showed a statistically significant benefit in the global intention-to-treat (ITT) population. The hazard ratio for overall survival was 0.76 (95% CI: 0.61 – 0.95; nominal p=0.0151) for ivonescimab plus chemotherapy compared to placebo plus chemotherapy. In the primary analysis performed in April 2025, the hazard ratio was 0.79 (95% CI: 0.62 – 1.01; p=0.057), which did not reach statistical significance. The updated data indicates that with longer follow-up—specifically a median follow-up time of 23.2 months for western patients—the survival benefit observed in Asian patients was replicated in the western patient subgroup.
The filing also includes data from the HARMONi-2 trial, a single-region Phase III study conducted in China sponsored by Summit’s partner, Akeso Inc. In the protocol-specified interim analysis of OS, ivonescimab monotherapy demonstrated a statistically significant improvement compared to pembrolizumab monotherapy, achieving a hazard ratio of 0.73 (95% CI: 0.57, 0.95; p=0.009). The median overall survival was 30.8 months for the ivonescimab group versus 22.6 months for the pembrolizumab group.
Summit noted that the safety profiles for both trials remained acceptable and manageable, with no new safety signals observed in the latest data cuts. The company stated that its Biologics License Application (BLA) with the U.S. Food and Drug Administration (FDA) is based on the HARMONi trial results and has a Prescription Drug User Fee Act (PDUFA) goal action date of November 14, 2026.
