Comparative Study Between Belotecan/Cisplatin and Etoposide/Cisplatin (COMBAT) in Patients with Previously Untreated, Extensive Stage Small Cell Lung Cancer - Interim Analysis

Purpose Belotecan (camtobell™) is a topoisomerase I inhibitor, and effective in small cell lung cancer (SCLC). The objective of this study is to compare the efficacy and safety of belotecan + cisplatin (BP) and etoposide + cisplatin (EP) in first line setting. Methods (materials) This is a multicenter, randomized, prospective controlled trial to prove non-inferiority of BP compared to standard EP regimen. The primary endpoint is overall response rate (ORR), and secondary endpoints are toxicity, overall survival (OS) and progression-free survival (PFS). BP was administrated by belotecan 0.5 mg/m2 for 4 days combined with cisplatin 60 mg/m2 only for first day. Treatment response was evaluated according to version 1.0 of Response Evaluation Criteria in Solid Tumors. Results We enrolled 129 (BP: 63, EP: 66) patients, and response evaluation was possible in 111 (BP: 50, EP: 61) patients. In BP group, there were 1 complete response, 32 partial responses (PR), 7 stable diseases (SD), and there were 33 PR and 11 SD in EP group. There were no significant differences in ORR (BP: 66.0%, EP: 54.1%, p = 0.25) and disease control rate (BP: 80.0%, EP: 72.1%, p = 0.38). Median OS (BP: 483, EP: 340 days, p = 0.21) and PFS (BP: 192, EP: 150 days, p = 0.08) were not significantly different. The frequency of grade ≥ 3 anemia (BP: 29.0%, EP: 7.5%, p Conclusions In this interim analysis, BP and EP have similar ORR, OS and PFS in extensive stage SCLC. Toxicity profiles except anemia and thrombocytopenia were similar between two groups. (ClinicalTrials.gov number, NCT00826644) Disclosure All authors have declared no conflicts of interest.