Intercalated chemotherapy and erlotinib for non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations

Among attempts to delay development of resistance to tyrosine kinase inhibitors (TKIs) in patients with advanced non-small cell lung cancer (NSCLC) with activating mutations of epidermal growth factor receptor (EGFR), intercalated therapy has not been properly evaluated. In a phase II trial, 38 patients with EGFR mutated NSCLC in advanced stage were treated with 4 to 6 3-weekly cycles of intercalated schedule with gemcitabine (1250mg/m2, days 1 and 4), cisplatin (75mg/m2, day 2) and erlotinib (150mg, days 5 - 15), followed by continuous erlotinib as maintenance. In addition to standard radiologic evaluation according to RECIST, PET/CT was done prior to treatment and at 6months, using PERCIST as a method for assessment of response. The primary endpoint was progression-free survival (PFS). In general, tolerance to treatment was good, even among 8 patients with performance status 2-3 and 13 patients with brain metastases; grade 4 toxicity included 2 cases of neutropenia and 4 thrombo-embolic events. Complete response (CR) or partial response (PR) were seen in 15 (39.5%) and 17 (44.7%) cases, respectively. All cases of CR were confirmed also by PET/CT. Median PFS was 23.4months and median overall survival (OS) was 38.3months. After a median follow-up of 35months, 8 patients are still in CR and on maintenance erlotinib. In conclusion, intercalated treatment for treatment-naive patients with EGFR activating mutations leads to excellent response rate and prolonged PFS and survival. Comparison of the intercalated schedule to monotherapy with TKIs in a randomized trial is warranted.