In the United States and Europe, the combination of oral UFT plus
leucovorin has been reported to produce objective responses and survival rates similar to those achieved with standard intravenous
5-fluorouracil plus
leucovorin in patients with metastatic
colorectal cancer, with reduced toxicity. However, because knowledge and experience with UFT plus
leucovorin are relatively limited in Japan, we conducted a phase II study to evaluate the safety and efficacy of this combination in Japanese patients with metastatic
colorectal cancer. For the purposes of this study, 20 patients received oral UFT 400 mg/m2/day in two divided doses (q 12 h) and a 5-mg
tablet of
leucovorin (q 8 h). Treatment was administered for 5 days, followed by a 2-day rest period, for a 28-day cycle. There were six partial responses (30%) and one complete response (5%) (overall response rate, 35%; 95% confidence interval, 14.1% to 55.9%). Greater efficacy of UFT plus
leucovorin was demonstrated in patients with lung
metastases, with a response rate of 63% (five of eight patients). Patients received a median of 4.5 courses (range, 2 to 12) of
therapy. The median duration of survival was 228+ days (range, 81 to 540; six patients remain alive). Grade 3 or 4 toxicities occurred in three patients:
diarrhea in two and
mucositis in one. No toxicity-related hospitalization was reported. In summary, this combination showed promising activity and an acceptable toxicity profile in the treatment of Japanese patients with metastatic
colorectal cancer.