OBJECTIVE Pemetrexed has been approved for second-line treatment in non-small cell lung cancer (NSCLC). However, the role of third-line pemetrexed therapy in NSCLC has not yet been generally accepted. We attempted to validate third-line pemetrexed therapy and evaluate predictive factors for pemetrexed therapy for NSCLC.

METHODS Medical records of NSCLC patients who received pemetrexed therapy that progressed after systemic therapy were reviewed retrospectively. We stratified patients according to clinicopathologic characteristics to find predictive factors for pemetrexed therapy.

RESULTS A total of 100 patients were eligible for analysis, and overall progression-free survival (PFS) was 3.03 months. The objective response rate was 12%, and the toxicity profile was favorable. Pemetrexed was used as a second-line treatment in 30% of patients, and as third- or further-line treatment in 70%. Comparing the efficacy of pemetrexed in these two settings (second-line versus third- or further-line), there was no significant difference in terms of PFS (3.07 versus 2.83 months, P = 0.86). When we evaluated predictive factors by multivariate analysis, performance status significantly influenced PFS.

CONCLUSIONS Pemetrexed is a suitable third-line treatment option with good efficacy and tolerable toxicity profile for NSCLC.