UFT® plus oral leucovorin calcium (Orzel™) and radiation in combined modality therapy: A comprehensive review

5‐fluorouracil (5‐FU) has become the most commonly used drug in combination with radiation therapy. The recent availability of oral formulations of 5‐FU in conjunction with the ability to modulate the anabolic and catabolic metabolism of 5‐FU with leucovorin and dihydropyrimidine dehydrogenase (DPD) inhibitors, respectively, may provide a substantial improvement in the ease of administration and the efficacy of fluoropyrimidine therapy. Several oral fluoropyrimidines are under investigation. UFT (uracil:tegafur) plus oral leucovorin (Orzel™) is the first oral DPD‐inhibitory fluoropyrimidine. With daily administration, Orzel achieves similar concentrations of 5‐FU obtained with continuous‐infusion 5‐FU. This paper summarizes the therapeutic rationale for Orzel and reviews the clinical experience with UFT and UFT/LV in combined modality therapy regimens. Int. F. Cancer (Radiat. Oncol. Invest.) 96, 1–10 (2001). © 2001 Wiley‐Liss, Inc.