Background: Gefitinib and erlotinib are commonly used for salvage therapy in patients with nonsmall cell lung cancer (NSCLC) who have progressed on prior therapies. Although both agents have similar structure and have demonstrated efficacy in NSCLC, gefitinib and erlotinib have not been directly compared in terms of efficacy and other clinical outcomes in patients with NSCLC who have failed prior chemotherapy. This prompted us to analyze the clinical outcomes between gefitinib-treated and erlotinib-treated patients with metastatic or recurrent NSCLC.
Methods: A total of 467 patients with metastatic or recurrent NSCLC who had progressed on prior therapies and received gefitinib or erlotinib therapy between January 2006 and December 2008 were retrospectively reviewed. By using a matched-pair case-control study design, 171 pairs of gefitinib-treated and erlotinib-treated patients were matched according to sex, Eastern Cooperative Oncology Group (ECOG) performance status, histologic type, and smoking history.
Results: The median age of all patients was 58 years (range, 20-85 years), and the median ECOG performance status was 1 (range, 0-3). Of 342 patients, 294 (86%) received an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor as second-line or third-line therapy, whereas the remaining 14% had received >2 prior chemotherapy regimens before starting EGFR TK inhibitor therapy. The confirmed overall response rate was 35.1%, and the disease control rate was 64%. With 13.2 months of follow-up, the median overall survival (OS) for the total 342 patients was 12.4 months (95% confidence interval [95% CI], 10.66-14.14 months), and the median progression-free survival (PFS) was 3.2 months (95% CI, 2.65-3.75 months). The overall response rates and disease control rates in the gefitinib-treated and erlotinib-treated groups were 38% versus 32.2% (P = .273) and 63.2% versus 64.9%, respectively (P = .677). There was no statistically significant difference noted with regard to OS (median, 12.6 vs 12.1 months; P = 0.99) and PFS (median, 4.6 vs 2.7 months; P = .06) between the gefitinib-treated and erlotinib-treated groups.
Conclusions: This retrospective analysis shows that gefitinib and erlotinib appear to have similar antitumor activity in terms of response rate and OS in pretreated patients with metastatic or recurrent NSCLC. Further prospective studies are warranted to elucidate any potential differences in toxicity and in dose intensity between gefitinib- and erlotinib-treated patients.