Current Development of Anti-Cancer Drug S-1.

S-1 is a novel oral fluoropyrimidine derivative, widely used for treating gastric, pancreatic, lung, head, neck and breast carcinomas. It is designed to enhance the clinical utility of an oral fluoropyrimidine and is associated with low gastrointestinal toxicity. S-1 consists of three pharmacological agents (at a molar ratio of 1:0.4:1)-Tegafur (FT), a prodrug of 5-Fluorouracil (5-FU), 5-Chloro-2-4-Dihydroxypyridine (CDHP), which inhibits the activity of Dihydropyrimidine Dehydrogenase (DPD) and Oxonic Acid (Oxo), which reduces Gastrointestinal (GI) toxicity of 5-FU. The present article reviews the current development of clinical study of S-1.