Prior EGFR tyrosine-kinase inhibitor therapy did not influence the efficacy of subsequent pemetrexed plus platinum in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma

Jeng-Sen Tseng,1,2 Tsung-Ying Yang,2 Kun-Chieh Chen,1,2 Kuo-Hsuan Hsu,1,3 Chong-Jen Yu,4 Wei-Yu Liao,4 Chi-Ren Tsai,5,6 Meen-Hsin Tsai,2,7 Sung-Liang Yu,8–11 Kang-Yi Su,8,12 Jeremy JW Chen,1 Hsuan-Yu Chen,7 Gee-Chen Chang1,2,13–151Institute of Biomedical Sciences, National Chung-Hsing University, 2Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, 3Division of Critical Care and Respiratory Therapy, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, 4Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, 5Department of Pediatrics, Taichung Veterans General Hospital, 6Institute of Molecular Biology, National Chung-Hsing University, Taichung, 7Institute of Statistical Science, Academia Sinica, 8Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, 9Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, 10Graduate Institute of Pathology, College of Medicine, National Taiwan University, 11Department of Laboratory Medicine, National Taiwan University Hospital, 12Center of Genomic Medicine, National Taiwan University, Taipei, 13School of Medicine, China Medical University, 14Comprehensive Cancer Center, Taichung Veterans General Hospital, Taichung, 15Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, TaiwanBackground: Tumor cells before and after epidermal growth-factor receptor (EGFR) tyrosine-kinase inhibitor (TKI) therapy might display different characteristics. The aim of this study was to evaluate the influence of prior EGFR TKI therapy on the efficacy of subsequent pemetrexed plus platinum (PP) in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma.Materials and methods: Advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma receiving PP as first-line chemotherapy were enrolled retrospectively in two medical centers of Taiwan. The objective of this study was to compare objective response rate (ORR), disease-control rates (DCR), progression-free survival (PFS), and overall survival (OS) of PP in patients with and without prior EGFR TKI therapy.Results: In total, 105 patients were analyzed. Sixty-one patients (58.1%) had prior EGFR TKI therapy and used PP as second-line treatment. The other 44 patients (41.9%) received PP as first-line therapy. ORRs of PP in patients with and without prior EGFR TKI therapy were 24.6% and 38.6%, respectively (P=0.138). DCRs of the two groups were 62.3% and 65.9%, respectively (P=0.837). The median PFS (6.1 versus 6.1 months, P=0.639) and OS (34.4 versus 32.3 months, P=0.394) were comparable between the groups with and without prior EGFR TKI therapy. In a subgroup analysis of patients with prior EGFR TKI therapy, there was no significant association between the efficacy of first-line EGFR TKI and the outcome of subsequent PP therapy.Conclusion: Our results suggested that prior EGFR TKI therapy would not influence the efficacy of subsequent PP therapy in advanced chemonaïve patients with EGFR-mutant lung adenocarcinoma.Keywords: non-small-cell lung cancer, epidermal growth-factor receptor mutation, epidermal growth-factor receptor tyrosine-kinase inhibitor, pemetrexed