Clinical experience with tegafur and low dose oral leucovorin: a dose-finding study

Tegafur is an effective oral fluoropyrimidine that shows the same activity as 5-fluorouracil for a similar spectrum of cancers. Their biochemical modulation with oral Leucovorin (LV) attempts to simulate treatment with a continuous infusion of 5-fluorouracil and LV with the added advantage of outpatient administration. Thirty-three patients with advanced adenocarcinoma were included in the study. The treatment consisted of tegafur, 0.75 g/m2/day, for 21 days, with oral LV at different dose levels, 15, 30, 45, 60 and 90 mg/day, in a 28-day cycle. A correlation between the LV dose and an increase in grade III/IV toxicity (especially diarrhea, oral mucositis and fatigue) was established in the nonlinear regression model, reaching a plateau at 60 mg of LV. For the tegafur dose used, the recommended dose of LV is in the range of 45-60 mg/day. This schedule could be considered to evaluate the possible therapeutic effect in phase II trials.