Purpose: This randomized phase III trial was conducted to confirm noninferiority of amrubicin plus cisplatin (AP) compared with irinotecan plus cisplatin (IP) in terms of overall survival (OS) in chemotherapy-naive patients with extensive-disease (ED) small-cell lung cancer (SCLC).
Patients and methods: Chemotherapy-naive patients with ED-SCLC were randomly assigned to receive IP, composed of irinotecan 60 mg/m(2) on days 1, 8, and 15 and cisplatin 60 mg/m(2) on day 1 every 4 weeks, or AP, composed of amrubicin 40 mg/m(2) on days 1, 2, and 3 and cisplatin 60 mg/m(2) on day 1 every 3 weeks.
Results: A total of 284 patients were randomly assigned to IP (n = 142) and AP (n = 142) arms. The point estimate of OS hazard ratio (HR) for AP to IP in the second interim analysis exceeded the noninferior margin (HR, 1.31), resulting in early publication because of futility. In updated analysis, median survival time was 17.7 (IP) versus 15.0 months (AP; HR, 1.43; 95% CI, 1.10 to 1.85), median progression-free survival was 5.6 (IP) versus 5.1 months (AP; HR, 1.42; 95% CI, 1.16 to 1.73), and response rate was 72.3% (IP) versus 77.9% (AP; P = .33). Adverse events observed in IP and AP arms were grade 4 neutropenia (22.5% v 79.3%), grade 3 to 4 febrile neutropenia (10.6% v 32.1%), and grade 3 to 4 diarrhea (7.7% v 1.4%).
Conclusion: AP proved inferior to IP in this trial, perhaps because the efficacy of amrubicin as a salvage therapy was differentially beneficial to IP. IP remains the standard treatment for extensive-stage SCLC in Japan.