A nucleoside analog; converted intracellularly to 3-deazauridine triphosphate, which inhibits the biosynthesis of CTP; inhibits the growth of L1210 leukemia cells when used at a concentration of 6 μM; dose-dependently reduces mortality in a mouse model of leukemia; enhances the incorporation of decitabine into DNA in leukemia cells when used at a concentration of 20 μM; reduces mortality when used at a dose of 100 or 150 mg/kg and combined with decitabine in a mouse model of leukemia