First-Line Pemetrexed plus Cisplatin followed by Gefitinib Maintenance Therapy versus Gefitinib Monotherapy in East Asian Never-Smoker Patients with Locally Advanced or Metastatic Nonsquamous Non-Small Cell Lung Cancer: Final Overall Survival Results from a Randomized Phase 3 Study

Introduction: The primary analysis of this open-label, randomized, multicenter phase 3 study revealed no significant difference in progression-free survival between pemetrexed plus cisplatin followed by maintenance gefitinib (PC/G) and gefitinib monotherapy (G) in patients with advanced nonsquamous non-small cell lung cancer (NSCLC) and unknown epidermal growth factor receptor gene (EGFR) mutation status; however, the hazard ratio favored PC/G. This report describes the final overall survival (OS) results.

Methods: Chemonaive, East Asian light ex-smokers/never-smokers with advanced nonsquamous NSCLC and unknown EGFR mutation status were randomized (1:1) to PC/G (n = 118) or G (n = 118). EGFR mutation status was retrospectively determined for 76 patients, 52 (68.4%) of whom had EGFR-mutated tumors (exon 19 deletions in 26 and L858R point mutation in 24). OS was analyzed by the Kaplan-Meier method. The study was registered at ClinicalTrials.gov (NCT01017874).

Results: Median OS was similar in the PC/G (26.9 months) and G (27.9 months) groups (hazard ratio = 0.94, 95% confidence interval: 0.68-1.31, p = 0.717). Median OS was longer with PC/G than with G in patients with EGFR wild-type tumors (28.4 versus 8.9 months) and longer with G than with PC/G in patients with EGFR-mutated tumors (45.7 versus 32.4 months), especially those with exon 19 deletions. Second-line postdiscontinuation therapy was common and included chemotherapy (PC/G, 41 of 118 [34.7%]; G, 73 of 118 [61.9%]) and rechallenge with an EGFR tyrosine kinase inhibitor (PC/G, 27 of 118 [22.9%]; G, 9 of 118 [7.6%]).

Conclusions: The progression-free survival and OS results from this study further demonstrate the importance of determining EGFR mutation status to select the most appropriate first-line treatment for patients with advanced NSCLC.