The New England Journal of Medicine October 29, 2020

Osimertinib in Resected EGFR-Mutated Non–Small-Cell Lung Cancer

Yi-Long Wu, Masahiro Tsuboi, Jie He, et al.

Bottom Line

In patients with completely resected stage IB to IIIA EGFR-mutated non-small-cell lung cancer, three years of adjuvant osimertinib produced an unprecedented 83% reduction in the risk of disease recurrence or death compared to placebo.

Key Findings

1. Among patients with stage II to IIIA disease (primary analysis population), the 24-month disease-free survival rate was 90% with osimertinib compared to 44% with placebo (HR 0.17; 99.06% CI, 0.11 to 0.26; P<0.001).

2. In the overall population (stage IB to IIIA), 89% of patients in the osimertinib group versus 52% in the placebo group were alive and disease-free at 24 months (HR 0.20; 99.12% CI, 0.14 to 0.30; P<0.001).

3. Adjuvant osimertinib significantly reduced the risk of central nervous system (CNS) recurrence, with 98% of patients in the osimertinib arm remaining alive and CNS-disease-free at 24 months versus 85% in the placebo arm.

4. At the time of this primary analysis, overall survival data were immature with only 29 deaths reported overall (9 in the osimertinib group and 20 in the placebo group).

Study Design

Design

Phase 3 RCT

Double-Blind

Sample

682

Patients

Duration

22.1 mo

Median

Setting

Multicenter, Global

Population Adults with completely resected stage IB to IIIA non-small-cell lung cancer harboring EGFR exon 19 deletions or L858R mutations, with or without previous adjuvant chemotherapy.

Intervention Osimertinib 80 mg orally once daily for up to 3 years.

Comparator Matched placebo orally once daily for up to 3 years.

Outcome Investigator-assessed disease-free survival (DFS) among patients with stage II to IIIA disease.

Study Limitations

• Overall survival data were highly immature at the time of the primary publication, leading to initial debates regarding whether the drug prevented recurrence or simply delayed it (though a 2023 follow-up update later confirmed a significant OS benefit).

• Early unblinding by the Independent Data Monitoring Committee due to overwhelming efficacy resulted in truncated follow-up for long-term safety and DFS.

• Adjuvant chemotherapy was not mandated and was left to investigator discretion (administered in approximately 60% of patients), raising questions about the optimal sequencing and absolute necessity of chemotherapy.

• Uncertainty remained regarding the optimal duration of adjuvant targeted therapy beyond the 3 years evaluated in the trial.

Clinical Significance

The ADAURA trial fundamentally shifted the perioperative treatment paradigm for non-small-cell lung cancer. By demonstrating a massive disease-free survival benefit (HR 0.17), it established adjuvant osimertinib as the new standard of care for patients with resected stage IB-IIIA EGFR-mutated NSCLC. It proved that precision targeted therapies—historically confined to the advanced/metastatic setting—could be highly efficacious in early-stage, localized disease, paving the way for biomarker testing in all patients with resected NSCLC.

Historical Context

Historically, the standard of care for completely resected early-stage NSCLC was platinum-doublet adjuvant chemotherapy, which provided a modest 5% absolute survival benefit at 5 years with substantial toxicity. While EGFR tyrosine kinase inhibitors (TKIs) had transformed the management of advanced EGFR-mutated NSCLC, previous attempts to bring first-generation TKIs (like gefitinib or erlotinib) into the adjuvant setting (such as the ADJUVANT/CTONG1104 trial) yielded improvements in disease-free survival but failed to show a definitive overall survival advantage. Osimertinib, a 3rd-generation, CNS-penetrant EGFR TKI, had already established superiority in the first-line advanced setting (FLAURA trial), providing a strong rationale for the ADAURA trial to test its efficacy in early-stage, localized disease.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

Osimertinib is a third-generation EGFR tyrosine kinase inhibitor. How does its mechanism of action differ from first-generation TKIs like erlotinib, particularly regarding its target affinity and ability to cross the blood-brain barrier, and why is this relevant in early-stage NSCLC?

Key Response

Tests understanding of irreversible binding, sparing of wild-type EGFR, targeting T790M, and high CNS penetrance, which is crucial since brain metastases are a common and morbid site of recurrence in EGFR-mutated NSCLC.

Resident

The ADAURA trial allowed patients to receive standard adjuvant chemotherapy before starting osimertinib. Based on current standard-of-care pathways, how do you decide which patients with completely resected stage II-IIIA EGFR-mutated NSCLC should receive adjuvant chemotherapy prior to starting osimertinib, rather than proceeding directly to targeted therapy?

Key Response

Bridges trial design with real-world clinic. Adjuvant chemotherapy provides a known overall survival benefit; osimertinib is given after chemotherapy, not as a replacement, requiring shared decision-making regarding cumulative toxicity.

Fellow

Following 3 years of adjuvant osimertinib, a key concern is the pattern of recurrence and acquired resistance. If a patient experiences disease recurrence at year 4 (off therapy), how does the approach to molecular testing and systemic therapy differ compared to a patient who relapses while on active adjuvant therapy at year 2?

Key Response

Pushes the fellow to evaluate acquired resistance mechanisms requiring alternative therapies versus the potential for TKI rechallenge if the relapse occurs after a significant treatment-free interval.

Attending

The striking 83 percent reduction in disease recurrence brings into question whether we are curing more patients or simply delaying inevitable micrometastatic progression. How do you counsel a healthy, asymptomatic patient with stage IB disease about committing to 3 years of a costly therapy with potential toxicities, given that many stage IB patients are cured by surgery alone?

Key Response

Addresses the art of medicine, cost-benefit analysis, financial toxicity, and the challenge of potentially over-treating the subset of early-stage patients already cured by surgical resection.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

The ADAURA trial was unblinded early due to crossing the prespecified efficacy boundary for disease-free survival (DFS). What are the statistical and methodological risks of early trial termination based on a surrogate endpoint like DFS, and how might this impact the estimation of the ultimate overall survival (OS) benefit?

Key Response

Explores the statistical phenomenon of overestimating treatment effect (the winner's curse) when stopping early, and evaluates the validity of DFS as a surrogate endpoint for OS in adjuvant solid tumor trials.

Journal Editor

As a reviewer evaluating the ADAURA manuscript, a critical point of contention is post-recurrence therapy in the control arm. Given that only a subset of placebo patients received osimertinib upon recurrence, how does this crossover rate threaten the validity of downstream overall survival claims?

Key Response

Highlights a major critical appraisal focal point: if the control arm does not reliably receive the standard-of-care therapy upon relapse, the overall survival benefit of the experimental arm may be artificially inflated, complicating editorial endorsement.

Guideline Committee

Current ASCO and NCCN guidelines strongly recommend adjuvant osimertinib for resected stage IB-IIIA EGFR-mutated NSCLC. However, the trial utilized AJCC 7th edition staging rather than the current 8th edition. How should the committee address the discrepancy in stage IB definitions between editions when defining the exact patient population eligible for this Category 1 recommendation?

Key Response

Guideline committees must translate trial inclusion criteria to contemporary practice. Discrepancies in tumor size and pleural invasion criteria between AJCC 7th and 8th editions require explicit clarification to prevent under- or over-prescription of adjuvant therapy.

Clinical Landscape

Noteworthy Related Trials

2018

FLAURA Trial

n = 556 · NEJM

Tested

Osimertinib 80mg daily

Population

Treatment-naive advanced EGFR-mutated NSCLC

Comparator

Standard EGFR-TKIs (Gefitinib or Erlotinib)

Endpoint

Progression-free survival (PFS)

Key result: Osimertinib significantly improved median progression-free survival (18.9 vs 10.2 months) and overall survival compared to standard first-generation EGFR-TKIs.

2018

ADJUVANT/CTONG1104 Trial

n = 222 · Lancet Oncol

Tested

Gefitinib 250mg daily for 24 months

Population

Completely resected stage II-IIIA EGFR-mutant NSCLC

Comparator

Vinorelbine plus cisplatin (chemotherapy)

Endpoint

Disease-free survival (DFS)

Key result: Adjuvant gefitinib significantly prolonged DFS (28.7 months vs 18.0 months) compared to standard chemotherapy, with less toxicity.

2021

IMpower010 Trial

n = 1005 · Lancet

Tested

Atezolizumab 1200mg every 3 weeks

Population

Completely resected stage IB-IIIA NSCLC after adjuvant chemotherapy

Comparator

Best supportive care

Endpoint

Disease-free survival (DFS)

Key result: Atezolizumab showed a significant disease-free survival benefit over best supportive care, particularly in patients with PD-L1 positive stage II-IIIA disease.

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