[Efficacy of erlotinib after the failure of gefitinib in patients with metastasis of non-small cell lung cancer with unknown EGFR mutation status].

Objective: To evaluate the efficacy of erlotinib in patients with metastasis of non-small cell lung cancer who had benefits from initial gefitinib treatment but finally demonstrated resistance, especially in those of unknown EGFR mutation status, and to compare the efficacy of erlotinib between patients who received erlotinib immediately after gefitinib failure and those who received chemotherapy before erlotinib.

Methods: Forty Chinese patients who had been treated with erlotinib (150 mg daily) after gefitinib (250 mg daily) failure were evaluated retrospectively. All of these patients had achieved gefitinib treatment for at least three months with response of partial remission or stable disease. Among them, 16 patients shifted to erlotinib immediately after progression (Group G-E), and the other 24 patients inserted chemotherapy between gefitinib and erlotinib (Group G-C-E).

Results: In the whole group, the disease control rate (DCR) of erlotinib was 52.5% (21/40) while the objective response rate (RR) was only 10.0% (4/40). The RR of the group G-E was 6.2% and the group G-C-E was 12.5%, and the DCR was 56.2% and 50.0% in the two groups, respectively, both without significant differences (P = 0.638 and P = 0.755). There was no correlation between the efficacy of erlotinib and that of initial gefitinib in both group G-E and group G-C-E (P = 0.365 and P = 0.658). The median progression-free survival (PFS) and overall survival (OS) for the erlotinib treatment were 3.0 and 12.0 months in the 40 patients. Statistically no significant difference was observed in PFS (4 months in the group G-E and 2 months in the group G-C-E, P = 0.768) and OS (12 months in both Groups, P = 0.510).

Conclusions: Erlotinib can be considered either immediately after gefitinib failure or following the insertion of chemotherapy after gefitinib failure in progressive non-small cell lung cancer patients who initially benefited from gefitinib.