S 1 (combination) [ BMS 247616,BMS247616,S-1 (combination),S-1 cpd,S1-fluoropyrimidine oxoonate combination,S1-tegafur-oxonate combination,TS-1 cpd ] consists of tegafur, 5-chloro-2,4-dihydroxyuridine & potassium oxonate; an inhibitor of fluorouracil(5-FU) degradation; prolongs the blood 5-FU level as well as increases selective toxicity to tumor;