Randomized phase II study of carboplatin plus irinotecan versus carboplatin plus amrubicin in patients with chemo-naïve extensive-stage small-cell lung cancer: North Japan Lung Cancer Study Group (NJLCG) 0901

•Developing aeffective carboplatin (C)-based regimen for SCLC patients is proposed.•This randomized phase II trial compared C/Amrubicin (CA) and C/Irinotecan (CI).•CA achieved a longer PFS than CI in patients with extended-stage SCLC.•The toxicity was acceptable in both arms, and no grade 5 event was observed.•CA is an appropriate regimen for comparison with Carboplatin/Etoposide.