Weekly irinotecan in patients with metastatic gastric cancer failing cisplatin-based chemotherapy

Background: The goal of this study is to determine the efficacy and toxicity of weekly irinotecan as second-line chemotherapy in advanced gastric cancer after failure of cisplatin-based regimen. Methods: Gastric cancer patients failing cisplatin-based chemotherapy received 125 mg/m² of irinotecan weekly for 4 weeks followed by 2-week rest, until disease progression. Results: Thirty-seven patients were enrolled into this study. The objective response was documented in seven of 35 patients with measurable lesion (response rate 20%, 95% CI: 6.1-33.9). Eight patients (22.9%) had stable disease and overall tumor control rate was 42.9%. The disease remained stable in both of two patients without measurable disease. At a median follow-up duration of 15.8 months, median time to progression and overall survival were 2.6 months (95% CI: 2.4-2.8) and 5.2 months (95% CI: 3.6-6.7), respectively. Neutropenia and diarrhea were the main toxicities. Among 37 patients treated, grade 3/4 (G3/4) neutropenia occurred in 43.2/24.3% of patients, respectively, and was accompanied with fever in three patients. Non-hematologic toxicities consisted mainly of delayed diarrhea (G3/4, 18.9/0%) and nausea/vomiting (G3/4, 18.9/0%). These toxicities were manageable and there was no treatment-related death. Conclusions: This weekly schedule of irinotecan was modestly active against cisplatin-refractory gastric cancer and relatively well-tolerated with appropriate dose modification.