Rationale: Gefitinib is effective in treating patients with non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Deletions in exon 19 and L858R in exon 21 are the best-documented EGFR mutations that are associated with effective gefitinib responsiveness.
Objectives: To clarify the influence of gefitinib timing, we conducted a study to compare the outcomes of different lines of gefitinib treatment in patients with exon 19 deletions or L858R.
Methods: We surveyed the clinical data and mutational studies of patients with NSCLC with EGFR mutations in the National Taiwan University Hospital (Taipei, Taiwan).
Measurements and main results: Three hundred and twenty-eight patients, who received gefitinib for stage IIIb or IV NSCLC, were adequately sequenced for EGFR mutations; 192 patients had mutant EGFR, including 77 patients with exon 19 deletions and 75 patients with L858R. The 152 patients with exon 19 deletions or L858R and who were receiving gefitinib were classified into a chemonaive group (91 patients) or a chemotherapy-treated group (61 patients). Chemonaive status before gefitinib and female sex were associated with clinical response to gefitinib (P = 0.006 and 0.053, respectively). Neither overall survival after the start of antitumor therapy nor progression-free survival after gefitinib therapy was significantly different between these two groups (P = 0.207 and 0.804, respectively). Clinical response to gefitinib was the only factor associated with better overall survival (P = 0.001).
Conclusions: This study suggests that gefitinib is effective in patients with EGFR mutations. The gefitinib response rate in chemonaive patients is higher than in chemotherapy-treated patients; however, there is no difference in overall survival.