Duration of prior gefitinib treatment predicts survival potential in patients with lung adenocarcinoma receiving subsequent erlotinib.

Purpose: We investigated survival potential in patients receiving erlotinib after failure of gefitinib, focusing on response and time to progression (TTP) with gefitinib.

Methods: We retrospectively reviewed lung adenocarcinoma patients who received erlotinib after experiencing progression with gefitinib. Our primary objective was to evaluate the prognostic significance of erlotinib therapy.

Results: A total 42 lung adenocarcinoma patients were included in this study. Overall disease control rate was 59.5% (partial response [PR], 2.4%; stable disease [SD], 57.1%). Median overall survival was 7.1 months, and median progression-free survival was 3.4 months. The number of patients who achieved PR and non-PR (SD+ progressive disease [PD]) with gefitinib were 22 (52%) and 20 (48%), respectively. Patients with PR for gefitinib showed significantly longer survival times than those with non-PR (9.2 vs. 4.7 months; p=0.014). In particular, among PR patients, those with TTP <12 months on gefitinib showed significantly longer survival times than those with TTP ≥12 months (10.3 vs. 6.4 months; p=0.04).

Conclusions: Erlotinib may exert survival benefit for lung adenocarcinoma patients with less than 12 months of TTP of prior gefitinib who achieved PR for gefitinib.