Erlotinib after gefitinib failure in relapsed non-small cell lung cancer: clinical benefit with optimal patient selection.

BACKGROUND: Recent reports have suggested that erlotinib therapy after gefitinib failure requires optimal patient selection to obtain clinical benefits in relapsed non-small cell lung cancer (NSCLC). However, insufficient evidence exists to determine which clinical factors best identify patients who benefit from erlotinib therapy.
METHODS: One hundred twenty-five patients with relapsed NSCLC who had received erlotinib therapy after gefitinib failure were retrospectively evaluated between January 2008 and May 2009.
RESULTS: The response rate (RR), disease control rate (DCR), and median progression-free survival (PFS) for all patients were 9% (95% confidence interval [CI], 5-15%), 44% (95% CI, 35-53%), and 2.0 months (95% CI, 1.4-2.5 months), respectively. The median survival time was estimated to be 11.8 months (95% CI, 6.4-16.0 months). Using multivariate analysis, good performance status (PS), EGFR mutation-positive status, and benefit from prior gefitinib therapy were identified as significant predictive factors for disease control. Using a proportional hazards model, benefit from prior gefitinib therapy, good PS, and insertion of cytotoxic chemotherapies between gefitinib and erlotinib therapies emerged as significant predictive factors for longer PFS. Thirty-two patients with concomitant PS 0/1, benefit from prior gefitinib therapy, and insertion of cytotoxic chemotherapies between gefitinib and erlotinib therapies benefitted more from erlotinib therapy: RR, 25% (95% CI, 12-43%); DCR, 72% (95% CI, 53-86%); and median PFS, 3.4 months (95% CI, 2.4-4.9 months).
CONCLUSIONS: Higher efficacy of erlotinib after gefitinib failure can be achieved with proper patient selection criteria, including good PS, benefit from prior gefitinib therapy, and insertion of cytotoxic chemotherapies between gefitinib and erlotinib therapies.