Clinical Activity of Afatinib in Patients With Non–Small-Cell Lung Cancer Harboring Uncommon EGFR Mutations: A Spanish Retrospective Multicenter Study

We report the results of the molecular and clinical characterization and the efficacy of afatinib in a cohort of patients with advanced non–small-cell lung cancer (NSCLC) patients harboring uncommon epidermal growth factor receptor (EGFR) mutations in Spanish clinical practice. In patients with uncommon EGFR-mutant NSCLC, the most common mutations occurred on exon 18 in amino acid G719, either alone or in combination with another mutation; other uncommon mutations were detected in exons 18, 19, 20, 21, and 22. In clinical practice, afatinib was active in patients with uncommon EGFR-mutant NSCLC, particularly in patients with complex and single mutations; however, in patients with EGFR ins20 (EGFR exon 20 insertions), treatment with afatinib provided a lower clinical benefit, indicating that further treatment strategies are needed for patients with this type of uncommon EGFR mutation.