Carboplatin and irinotecan (CI) vs. carboplatin and etoposide (CE) for the treatment of extended-stage small-cell lung cancer in an elderly population: A phase II/III randomized control trial

Abstract

Objectives: Cisplatin plus irinotecan has been considered as the standard therapy in younger (<70 years old) patients for extensive-disease small-cell lung cancer (ED-SCLC) in Japan. However, there is a lack of high-quality evidence for the use of irinotecan in elderly patients with ED-SCLC. This study aimed to demonstrate that carboplatin plus irinotecan (CI) improves overall survival (OS) in elderly patients with ED-SCLC.

Materials and methods: This was a randomized Phase II/III trial which enrolled elderly patients with ED-SCLC. Patients were randomized to the CI or carboplatin plus etoposide (CE) arm in a 1:1 ratio. The CE group intravenously received carboplatin (AUC 5 mg/ml/min on day 1) and etoposide (80 mg/m² on days 1-3) every 3 weeks for four cycles. The CI group received carboplatin (AUC 4 mg/ml/min on day 1) and irinotecan (50 mg/m² on days 1 and 8) intravenously every 3 weeks for 4 cycles.

Results: In total, 258 patients were enrolled and randomized (CE arm, 129 patients; CI arm, 129 patients). The median overall survival, progression-free survival, and objective response rate of the CE vs. CI arms were 12.0 (95% CI, 9.3-13.7) vs. 13.2 (95% CI, 11.1-14.6) months (HR, 0.85 (95% CI, 0.65-1.11)) (one-sided P = 0.11), 4.4 (95% CI, 4.0-4.7) vs. 4.9 (95% CI, 4.5-5.2) months (HR, 0.85 (95% CI, 0.66-1.09)), and 59.5% vs. 63.2%, respectively. A higher incidence of myelosuppression was observed in the CE group, whereas a higher incidence of gastrointestinal toxicity was observed in the CI group. Three treatment-related deaths occurred (one due to lung infection in the CE arm, and one due to lung infection and sepsis each in the CI arm).

Conclusions: The CI treatment showed favorable efficacy; however, the difference was not statistically significant. These results suggest that CE should remain as the standard chemotherapy regimen for elderly patients with ED-SCLC.

Keywords: Carboplatin; Elderly patients; Etoposide; Extensive-disease small-cell lung cancer; Irinotecan; Randomized phase II/III trial.