Comparison of the effectiveness of erlotinib, gefitinib, and afatinib for treatment of non-small cell lung cancer in patients with common and rare EGFR gene mutations

Abstract

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are routinely used to treat non-small cell lung cancer (NSCLC) in patients with common activating mutations of the <i>EGFR</i> gene. The aim of the study was to compare the efficacies of EGFR-TKIs in patients with common (exon 19 deletions and exon 21 p.Leu858Arg) and rare <i>EGFR</i> mutations. A retrospective analysis of 180 NSCLC patients with common (n=167) and rare (n=13) <i>EGFR</i> mutations treated with erlotinib (n=98), gefitinib (n=66) and afatinib (n=16) was performed. <i>EGFR</i> mutations were determined using RT-PCR and the EntroGen EGFR Mutations Analysis kit. Partial and complete response (PR and CR), progression-free survival (PFS), and overall survival (OS) were analyzed. Demographic and clinical factors had no impact on PFS or OS in patients treated with EGFR-TKIs. Erlotinib, gefitinib, and afatinib showed similar efficacies based on treatment response, median PFS, and OS. The type of <i>EGFR</i> mutation had no impact on median OS; however, median PFS was significantly longer in patients with the exon 19 deletion compared to patients with the exon 21 p.Leu858Arg substitution and rare <i>EGFR</i> gene mutations (P=0.013). Patients with common <i>EGFR</i> mutations showed significantly longer median PFS than those with rare <i>EGFR</i> mutations (10 vs. 5 months; P=0.009). Erlotinib, gefitinib, and afatinib show similar efficacies in NSCLC patients with both common and rare <i>EGFR</i> mutations. When undergoing EGFR-TKI treatment, patients with rare <i>EGFR</i> mutations showed similar OS but poorer PFS. Further investigation into the associations between particular rare <i>EGFR</i> mutations and EGFR-TKIs treatment outcomes is required.