Capecitabine plus oxaliplatin and irinotecan regimen every other week: a phase I/II study in first-line treatment of metastatic colorectal cancer

Background: A phase I/II study was performed to determine the safety and activity of a capecitabine plus oxaliplatin and irinotecan (COI) regimen using capecitabine concurrently with oxaliplatin and irinotecan in previously untreated patients with metastatic colorectal cancer. Patients and methods: Patients received irinotecan on day 1, oxaliplatin (85 mg/m2) on day 2 and capecitabine (1000 mg/m2 orally twice daily) on days 2–6 of a biweekly schedule. Three dose levels ranging from 150 to 180 mg/m2 were explored for irinotecan in sequential cohorts of three to six patients. Once the recommended dose was determined, a total of 28 eligible patients were planned at this dose level. Results: Thirty-eight patients received a median of six cycles. The recommended phase II dose of irinotecan was 180 mg/m2. Toxicity was manageable: the most common severe toxicities were diarrhoea (24%) and nausea (16%). Of 27 assessable patients treated at the recommended dose, 17 achieved a partial response (overall response rate (ORR) 63%; 95% confidece interval (CI), 44 to 78%), with eight patients undergoing liver metastasectomy. Estimated progression-free survival and overall median survival were 8.5 and 23.5 months, respectively. Conclusions: Biweekly COI is feasible and active. Tolerability and ease of administration make the regimen well suited for downsizing hepatic colorectal metastases before curative surgery.