FDA Declines to Approve Summit's Lung Cancer Drug Ivonescimab

The Food and Drug Administration has declined to approve ivonescimab, Summit Therapeutics' lung cancer drug, in a complete response letter the company announced on November 15, 2026. The application covered ivonescimab combined with platinum chemotherapy for patients with locally advanced or metastatic non-small cell lung cancer whose tumors carry EGFR mutations and who have already received an EGFR-targeted therapy.

The agency's reasoning fits in one sentence. Without a statistically significant improvement in overall survival, Summit hasn't established substantial evidence of effectiveness, and the drug's progression-free survival benefit doesn't support a positive benefit-risk profile on its own. Slowing a cancer's growth, the FDA is saying, isn't the same as proving that patients live longer.

The application rested on HARMONi, a global, randomized, double-blind Phase 3 trial that paired ivonescimab with chemotherapy against chemotherapy alone. HARMONi met its progression-free survival endpoint, and Summit notes it's the first global Phase 3 immunotherapy-based study to show a statistically significant progression benefit in this exact patient setting. The survival endpoint is where the trial fell short.

Summit's counterargument is about time. In the primary survival analysis, the drug showed a positive trend that didn't reach statistical significance. In a post-hoc analysis with longer follow-up, the company says the benefit settled into consistency, with a hazard ratio of 0.76 across the full population, Asian patients and Western patients alike. The FDA weighed that argument and declined anyway.

Context matters for patients reading this as a verdict on the drug class. Summit points out that no approved regimen has demonstrated a statistically significant overall survival benefit in this setting, which is part of why the application drew so much attention. Analysts at Leerink Partners had put the approval odds at 40 percent in a November 5 note, citing the same survival gap.

Ivonescimab is a bispecific antibody that blocks two targets at once, PD-1 and VEGF. It was first approved in China in May 2024, and it remains unapproved in the United States and Europe. A complete response letter isn't a ban. It means the application can't be approved in its present form, and the path back runs through the survival data the agency asked for.

The program doesn't stop here. Summit is running HARMONi-3, a Phase 3 trial of ivonescimab with chemotherapy in first-line metastatic lung cancer, with squamous and non-squamous cohorts analyzed separately, alongside further HARMONi studies in other settings. An interim look at HARMONi-3's squamous cohort missed statistical significance on progression earlier this year, which raises the stakes on the readouts still to come.

For the patients this application covered, the practical position doesn't change today. Their cancer has progressed after a third-generation EGFR inhibitor, the options remain limited, and the drug that delayed progression in a large global trial stays out of U.S. reach until its maker can show the benefit the FDA counts most: more life, measured tightly enough to prove it.