A National Cancer Institute of Canada Clinical Trials Group Study – IND.135: Phase I/II study of irinotecan (camptosar), oxaliplatin and raltitrexed (tomudex) (COT) in patients with advanced colorectal cancer

Thirty-one patients with metastatic colorectal cancer were enrolled in this phase I/II trial of a triple combination of camptosar (C), oxaliplatin (O) and tomudex (T), all given on day one of a convenient three-week schedule. Patients received 257 cycles (1–18) in five cohorts. Toxicity was manageable and haematological toxicity was mild to moderate. Diarrhoea was the main dose-limiting toxicity; nausea and vomiting were common. Fatigue was frequent, moderate in severity and a reason for discontinuation in some patients. The recommended phase II doses were (C) 220 mg/m2, (O) 100 mg/m2, (T) 2.75 mg/m2. A 50% response rate in 30 evaluable patients was confirmed by an independent radiology review board; progression-free survival and overall median survival were 7.3 months and 16.6 months, respectively. Of the 16 patients treated at the recommended dose, 9 (56.3%) experienced partial response. Further evaluation in a randomized study compared to sequential doublets is warranted. Triple combinations could be relevant in curative settings for high-risk patients.