Phase II Study of Irinotecan plus S-1 in Treatment of Advanced Gastric Cancer

Objective: The efficacy and safety of irinotecan hydrochloride (CPT-11) plus oral fluoropyrimidine S-1 combination therapy in patients with previously untreated advanced gastric cancer was evaluated. Methods: The regimen comprised CPT-11 plus S-1: CPT-11, 60 mg/m2 (days 1, 15); S-1, 40 - 60 mg/body twice daily (days 1 - 21) followed by a 1-week rest, every 4 weeks. Primary endpoint was response rate. Secondary endpoints were tumor control rate, adverse events, relative dose intensity, and overall survival. Results: Twenty-five patients were enrolled; median age was 66 years. Response rate was 40% (95% confidence interval, 21.1% - 61.3%; complete response in 1; partial response in 9). Tumor control rate was 56.0%, median survival time was 436 days and relative dose intensities were 0.83 for CPT-11 and 0.85 for S-1. Incidence of grade 3 or greater neutropenia, anemia and diarrhea was 16%, 12%, and 12%, respectively.Conclusion: The present results indicate that CPT-11 plus S-1 offers lower treatment-related toxicity than regimens including cisplatin and is effective in patients with advanced gastric cancer.