Eight years after randomization, 74% of patients with resected Stage II–IIIA EGFR-mutated non-small cell lung cancer (NSCLC) treated with adjuvant osimertinib (Tagrisso) were alive, compared with 58% of those who received placebo — a 16 percentage point gap that persisted despite high rates of crossover to osimertinib following disease recurrence. AstraZeneca presented the updated exploratory analysis from the ADAURA Phase III trial at the IASLC 2026 World Conference on Lung Cancer, simultaneously published in the Journal of Thoracic Oncology.
In the primary population (Stages II–IIIA), osimertinib reduced the risk of death by 47% versus placebo (hazard ratio 0.53; 95% CI 0.38–0.75). Across the overall trial population (Stages IB–IIIA), 79% of osimertinib-treated patients were alive at eight years versus 64% on placebo (HR 0.52; 95% CI 0.39–0.71). AstraZeneca described the analysis as exploratory, conducted in all 682 randomized patients with extended survival data available from approximately 77% of those still alive at the final planned overall survival (OS) analysis; 127 patients remained censored with survival time unchanged from that earlier cut. The safety profile was consistent with the established osimertinib label, with no new concerns identified.
This is notable because a substantial proportion of placebo patients crossed over to osimertinib after recurrence — a design feature that would be expected to dilute any survival separation. That the gap widened to 16 percentage points at 96 months, despite crossover, strengthens the case for early intervention over salvage use. Osimertinib selectively and irreversibly inhibits mutant EGFR isoforms, including the common exon 19 deletion and L858R variants, blocking the cell-signaling pathway that drives tumor growth in EGFRm NSCLC.
Osimertinib is a third-generation irreversible EGFR tyrosine kinase inhibitor targeting sensitizing EGFR mutations including exon 19 deletions and L858R. The drug is approved in more than 120 countries for several EGFR-mutated NSCLC settings, including adjuvant treatment following tumor resection. The US FDA approved the adjuvant indication in December 2020.