Afatinib Versus Osimertinib for Non-Small Cell Lung Cancer With Uncommon EGFR Mutations: Real-World Outcomes

Area of Science:

• Oncology
• Genomics
• Pharmacology

Background:

• Non-small cell lung cancer (NSCLC) with uncommon epidermal growth factor receptor (EGFR) mutations presents heterogeneous clinical challenges.
• Optimal first-line EGFR tyrosine kinase inhibitor (EGFR-TKI) and the role of immune checkpoint inhibitors (ICIs) remain unclear for these patients.

Purpose of the Study:

• To compare the efficacy and safety of first-line afatinib versus osimertinib in advanced non-squamous NSCLC patients with uncommon EGFR mutations.
• To evaluate the impact of subsequent therapies, including ICI-based regimens, after initial EGFR-TKI treatment.

Main Methods:

• Multicenter retrospective cohort study of 162 patients with advanced or recurrent non-squamous NSCLC and uncommon EGFR mutations (excluding exon 20 insertions and de novo T790M).
• Patients received either first-line afatinib or osimertinib between January 2015 and January 2024.
• Inverse probability of treatment weighting (IPTW) was used to adjust for baseline imbalances; treatment patterns and outcomes were analyzed.

Main Results:

• Weighted analyses revealed no significant differences in time to treatment failure (HR 1.04) or overall survival (HR 1.34) between afatinib and osimertinib.
• Afatinib was associated with higher response rates but more frequent adverse events requiring dose reduction.
• Subgroup analyses indicated differential effects: osimertinib favored L861X mutations, while afatinib favored compound mutations.
• Subsequent ICI plus platinum doublet therapy showed comparable outcomes to platinum doublet alone in 56 patients.

Conclusions:

• Afatinib and osimertinib offer comparable survival outcomes as first-line treatments for NSCLC with uncommon EGFR mutations.
• Treatment efficacy is influenced by specific molecular subtypes.
• Subsequent immune checkpoint inhibitor-based regimens appear to provide limited additional survival benefit.