Phase II study of UFT plus leucovorin in colorectal cancer.

The activity and toxicity of UFT (Tegafur and Uracil) in a 4:1 molar concentration, plus leucovorin (LV), were evaluated in the treatment of 45 patients with advanced, bidimensionally measurable metastatic colorectal carcinoma. Initially 350 and later 300 mg/m2/day, plus 150 mg LV, as administered in divided doses every 8 h for 28 days. After two courses of treatment, responses were evaluated. The overall response rate was 42.2%, with responses observed in liver (n = 18), lung (n = 6), and bone (n = 1). Five of the 7 patients who received 350 mg/m2 UFT experienced prolonged grade 3 diarrhea, resulting in a dose reduction to 300 mg/m2; 9 patients in the 300-mg/m2 group experienced grade 3 diarrhea, vomiting, abdominal cramping, and fatigue. Minor toxic effects included oral mucositis and rash. The oral regimen of 300 mg/m2/day UFT, plus 150 mg/day LV, administered for 28 days appears to have significant activity against metastatic colorectal carcinoma. The treatment is well tolerated; neutropenia did not occur, and oral mucositis was not significant, even though both are characteristic of intravenous schedules of 5-fluorouracil plus LV. The results of this trial constitutes the basis of phase III clinical trials comparing this oral schedule with intravenous 5-FU and LV to compare clinical efficacy, impact on well-being, and cost. In addition, the current National Surgical Adjuvant Breast and Bowel Project (NSABP) adjuvant colon clinical trial (CO-6) will compare this 28-day schedule of UFT plus oral leucovorin with a weekly regimen of intravenous 5-fluorouracil plus leucovorin in the postoperative adjuvant therapy of Dukes' B and C colon cancer patients.