An exploratory 8-year overall survival (OS) landmark analysis of the phase III ADAURA trial, presented at the 2026 World Conference on Lung Cancer, provides the longest OS follow-up data yet reported from any adjuvant global phase III trial in EGFR-mutated non-small cell lung cancer (NSCLC). The analysis evaluated adjuvant osimertinib versus placebo in patients with completely resected EGFR-mutated stage IB–IIIA NSCLC.
In the overall trial population (stage IB–IIIA), the 8-year OS rate was 79% with osimertinib versus 64% with placebo, a difference of 15 percentage points, with a hazard ratio of 0.52 (95% CI 0.39–0.71). Because this was a post hoc exploratory analysis conducted after the planned final OS data cut, these findings are hypothesis-generating and should be interpreted with appropriate caution.
Key finding
In this post hoc exploratory analysis of ADAURA, adjuvant osimertinib was associated with a 15 percentage-point improvement in 8-year OS rate versus placebo in resected EGFR-mutated stage IB–IIIA NSCLC (79% vs 64%; HR 0.52); because the analysis was conducted after the planned final OS data cut and used additional consent-based follow-up, results are considered exploratory and not confirmatory.
Study Design
| Trial | ADAURA (NCT02511106); global phase III, double-blind, randomized |
|---|---|
| Population | 682 patients (≥18 years; ≥20 in Taiwan/Japan) with WHO performance status 0/1 and completely resected EGFR-mutated stage IB–IIIA NSCLC (AJCC 7th edition); adjuvant chemotherapy permitted |
| Treatment | Osimertinib 80 mg once daily (n=339) or placebo (n=343) until disease recurrence, treatment completion (3 years), or another discontinuation criterion |
| Primary endpoint | Investigator-assessed disease-free survival (DFS) in patients with stage II–IIIA NSCLC |
| Key secondary endpoints | Overall survival (OS) in all randomized patients |
The current findings are a post hoc exploratory analysis of long-term OS. Among patients alive at the planned final OS analysis (data cut-off January 27, 2023; n=558), updated survival data were collected through yearly follow-up to a new data cut-off of May 4, 2026, either via active follow-up with additional consent (n=431) or from accessible records following the last contact date. Patients for whom no additional data were available (n=127) remained censored at their last known alive date from the original final analysis. All patients had already had the opportunity to complete 3 years of adjuvant study treatment.
Results and Safety
In the primary population of patients with stage II–IIIA disease, the 8-year OS rate was 74% (95% CI 67–80) with osimertinib versus 58% (95% CI 50–65) with placebo, representing a 16 percentage-point difference (HR 0.53; 95% CI 0.38–0.75; 142 events among 470 patients). Median OS follow-up was 92.0 months in the osimertinib arm and 68.5 months in the placebo arm. In the overall stage IB–IIIA population, the 8-year OS rate was 79% (95% CI 74–83) with osimertinib versus 64% (95% CI 58–70) with placebo (HR 0.52; 95% CI 0.39–0.71; 175 events among 682 patients), with median OS follow-up of 93.3 months versus 79.6 months, respectively. An OS benefit with osimertinib was observed across predefined subgroups, though specific subgroup data were not detailed in the abstract.
These results build on previously reported data from the planned final OS analysis, in which osimertinib demonstrated a statistically significant OS benefit (HR 0.49; p<0.001) and DFS benefit (HR 0.20; p<0.001) versus placebo at a median follow-up of approximately 60 months. Safety data were not reported in this exploratory analysis abstract.
Clinical Context
Three years of adjuvant osimertinib is the established standard of care for resected EGFR-mutated stage IB–IIIA NSCLC, supported by the statistically significant DFS and OS results from the planned ADAURA analyses. The 8-year exploratory data extend the observed survival signal beyond the treatment period, suggesting that the benefit persists well after completion of the 3-year adjuvant course. This is a clinically relevant question in a population where long-term outcomes have historically been difficult to characterize.
Because this analysis was post hoc and exploratory, used an additional consent-based data collection process, and included patients censored at different time points, definitive conclusions cannot be drawn. The asymmetry in median OS follow-up between arms, reflecting higher early mortality in the placebo group, also warrants consideration when interpreting the long-term curves. Further follow-up and reporting of subgroup-level and patient-level data will be needed to fully characterize the durability of benefit across different patient subsets.
Sources
- Herbst R et al. “Adjuvant Osimertinib in Resected EGFR-Mutated Stage IB-IIIA NSCLC: ADAURA Exploratory 8-year Overall Survival Landmark Update.” Conference abstract. IASLC World Conference on Lung Cancer 2026. Seoul, South Korea. View source.
AI disclosure: This article was prepared with assistance from generative AI using the source material cited above. It was reviewed and edited by Brandon Twyford before publication.