Efficacy of pemetrexed as second-line therapy in advanced NSCLC after either treatment-free interval or maintenance therapy with gemcitabine or erlotinib in IFCT-GFPC 05-02 phase III study

INTRODUCTION:: Maintenance therapy in advanced non-small-cell lung cancer (NSCLC) might lead to resistance to subsequent treatments. IFCT-GFPC 0502 study showed a progression-free survival (PFS) benefit with gemcitabine or erlotinib maintenance compared with observation after cisplatin-gemcitabine chemotherapy. The trial included a pre-defined pemetrexed second-line therapy, allowing post-hoc assessment of its efficacy according to previous maintenance treatment or treatment-free interval. METHODS:: Stage IIIB/IV NSCLC patients were randomized after four cycles of cisplatin-gemcitabine chemotherapy to either observation or to receive maintenance therapy with gemcitabine or erlotinib. Pemetrexed was given as second-line treatment on disease progression in all arms. PFS and overall survival (OS) were assessed from the beginning of pemetrexed therapy according to randomization arm. RESULTS:: Of the 464 randomized patients, 360 (78 %) received second-line pemetrexed (130 [84%], 114 [74%], and 116 [75%] in observation, gemcitabine, and erlotinib arm, respectively). Median number of pemetrexed cycles was 3 (1-40) in all arms. Median PFS did not differ between gemcitabine and observation arms (4.2 versus 3.9 months, hazard ratio [HR] [95% confidence interval [CI] 0.81 [0.62-1.06]) or between erlotinib and observation arms (4.2 versus 3.9 months, HR 0.83 [0.64-1.09]). OS data showed a non-significant improvement with gemcitabine arm versus observation arm (8.3 versus 7.5 months, HR 0.81 [0.61-1.07]) or erlotinib arm versus observation arm (9.1 versus 7.5 months, HR 0.80 [0.61-1.05]). Results were similar for non-squamous patients. Grade 3 to 4 treatment-related adverse events (AEs) were comparable in all arms. CONCLUSIONS:: Maintenance therapy with gemcitabine continuation or erlotinib does not seem to impair efficacy of second-line pemetrexed comparatively to administration after a treatment-free interval.