Efficacy and Safety of Afatinib for EGFR-mutant Non-small Cell Lung Cancer, Compared with Gefitinib or Erlotinib

PURPOSE: We tried to evaluate whether there are any specific features in treatment outcomes of firstline afatinib in patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC), compared with gefitinib or erlotinib. MATERIALS AND METHODS: We analyzed patients treated with first-line afatinib, gefitinib, or erlotinib for advanced EGFR-mutant NSCLC at Samsung Medical Center between 2014 and 2016. RESULTS: In total, 467 patients received first-line afatinib (n=165), gefitinib (n=230), or erlotinib (n=72). Afatinib was used more often in patients with tumors harboring deletion in exon 19 (Del19), whereas the gefitinib group had more elderly, females, and never smokers. The median progression-free survival (PFS) time for afatinib, gefitinib, and erlotinib was 19.1 months, 13.7 months, and 14.0 months, respectively (p=0.001). The superior PFS of afatinib was more remarkable in subgroups of Del19 or uncommon EGFR mutations. Overall toxicity profiles of the three drugs were comparable, though more grade 3 or 4 toxicities were detected in afatinib (7.3%) compared with gefitinib (2.6%) or erlotinib (1.8%). The common grade 3 or 4 toxicities of afatinib included diarrhea (3.0%), paronychia (2.4%), and skin rash (1.8%). Dose modification was more frequently required in patients treated with afatinib (112/165, 68%), compared with gefitinib (5/230, 2%) and erlotinib (4/72, 6%). Interestingly, however, dose reduction in the afatinib group did not impair its efficacy in terms of PFS (dose reduction vs. no reduction group, 23.5 months vs. 12.4 months). CONCLUSION: First-line afatinib showed satisfactory efficacy data and manageable toxicity profiles.