Phase II trial of high-dose continuous infusion 5-fluorouracii with allopurinol modulation in colon cancer

Twenty patients with metastatic colon cancer without prior chemotherapy received 2 g/m² of 5-fluorouracil (5-FU) infused over 24 h for 5 days preceded by allopurinol 900 mg orally for 1 week and then continued during, and for 1 week after the infusion was completed. Fourteen patients were evaluable for both response and toxicity. One patient (14%) achieved a partial response lasting 2 months. No significant hematologic toxicity was seen but 18 of 19 patients evaluable for toxicity developed mucositis resulting in dose reductions in 3 patients and refusal of a second course by 2 additional patients. 5-FU infusions with allopurinol as used in this regimen appear to offer no therapeutic advantage over a conventional dosing schedule.