Uracil-tegafur in gastric carcinoma: a comprehensive review

The second-generation oral anticancer agent UFT, a combination of uracil and tegafur (TGF), results in a higher fluorouracil (5-FU) concentration in the tumor tissues than is achieved by TGF or comparable doses of intravenous 5-fluorouracil. UFT has been extensively studied in Japan and has been in use in the Orient for many years, particularly for patients with gastric carcinoma. UFT has recently entered extensive investigations in North America and Europe.

Relevant studies that have chronicled the establishment of UFT, its mechanism of action, preclinical toxicology, human pharmacokinetics, phase I studies, and activity against gastric carcinoma are described in detail.

The uracil in UFT slows degradation of 5-FU by dihydropyrimidine dehydrogenase (DPD), which results in sustained concentrations of 5-FU in blood and tumor tissues. UFT is well tolerated, but such toxic effects as nausea, vomiting, and diarrhea are dose- and schedule-dependent. In phase I pharmacokinetic studies, UFT given orally on a 28-day schedule resulted in blood concentrations comparable to those following low-dose continuous intravenous infusion of 5-FU. In patients with gastric carcinoma, UFT alone has a response rate of approximately 20%. In the adjuvant setting, UFT plus mitomycin appears superior to TGF plus mitomycin. In Japan, UFT is part of the standard adjuvant chemotherapy for gastric carcinoma.

UFT is one of the first second-generation oral 5-FU prodrugs under investigation in North America and Europe. The literature suggests UFT is well tolerated and has cellular pharmacokinetic superiority over the first-generation 5-FU prodrug TGF. UFT has a more favorable toxicity profile than intravenous 5-FU. The issues of efficacy, patient convenience, and quality of life need to be studied in controlled randomized trials.