The relationship between response to previous systemic treatment and the efficacy of subsequent pemetrexed therapy in advanced non-small cell lung cancer.

BACKGROUND: We sought to identify the relationship between response to previous systemic treatment and the efficacy of subsequent pemetrexed therapy in advanced non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Two hundred and fifty clinical stage IIIB or IV NSCLC patients treated with pemetrexed as a second-line or further-line treatment between April 2007 and June 2008 were analyzed retrospectively. Prior therapies were divided into four types (gemcitabine-based [G], paclitaxel-based [P], docetaxel-based [D], and EGFR tyrosine kinase inhibitor [I]). Objective response rates (ORR) and progression-free survivals (PFS) for pemetrexed therapy were analyzed according to the response outcome with each previous treatment.
RESULTS: The ORR of pemetrexed therapy was higher for patients who had achieved partial response with previous [G] therapy than others (15.0% vs. 4.3%, p=0.02). In addition, median PFS for pemetrexed therapy was greater for responders to [G] than for nonresponders (3.0 months vs. 1.7 months, p=0.004). The longer PFS for responders to [G] was also shown in the analysis among patients with squamous cell carcinoma (3.2 months vs. 1.7 months, p=0.056). By univariate analyses, the variables of the responder to [G] therapy, female, adenocarcinoma, never smoking status, and ECOG performance status of 0-1 were good predictive factors for pemetrexed therapy in terms of PFS. Multivariate analysis revealed that only response to [G] had statistical significance (hazard ratio=0.62, p=0.006).
CONCLUSION: Response outcome to prior [G] therapy might predict the efficacy of subsequent pemetrexed therapy in advanced NSCLC. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.