PHASE-I TRIAL OF URACIL-TEGAFUR (UFT) PLUS ORAL LEUCOVORIN - 28-DAY SCHEDULE

UFT [Taiho Pharmaceutical Co. Ltd., Tokyo, Japan; (BMS-200604), Bristo l-Myers Squibb, Princeton, NJ], a fluorouracil prodrug, is an oral 4:1 molar concentration of uracil plus tegafur. This study examined the d ose-limiting toxic effects and maximum tolerated dose of UFT plus leuc ovorin administered for 28 consecutive days followed by a 7-day rest p eriod. A course of therapy was repeated every 35 days. UFT dose levels examined were 200 mg/m(2)/day, with planned escalations to 250, 300, 350, and 400 mg/m(2)/day; the leucovorin dose remained at 150 mg/day. Three patients were initially enrolled at each UFT dose level. The tot al daily doses of both UFT and leucovorin. were divided into three dos es administered every 8 hr: Diarrhea became the dose-limiting toxicity at 400 mg/m(2)/day UFT: with grade 3 diarrhea noted in 2 of the 3 pat ients receiving that dose. To further define a phase II UFT starting d ose, 3 additional patients were entered at the 350 mg/m(2) level; 3 of the 6 patients treated at this level developed grade 3 nonhematologic al toxic effects. No partial or complete responses were observed The r ecommended phase II UFT starring dose is 300 mg/m(2)/day plus 150 mg/d ay leucovorin. Since neutropenia, significant mucositis, and ''hand-fo ot syndrome'' were not observed with UFT plus leucovorin, the toxicity profile of this regimen appears favorable compared with that of intra venous regimens of fluorouracil plus leucovorin. This phase I trial of UFT served as the basis for a phase II trial, current phase III trial s, and a national adjuvant therapy trial of UFT for high-risk colon ca ncer patients.