(E)-5-(2-Bromovinyl)uracil (BVU) is a pyrimidine base and an inactive metabolite of the antiviral agents sorivudine and (E)-5-(2-bromovinyl)-2′-deoxyuridine (BVDU) that may be regenerated to BVDU in vivo. BVU irreversibly inactivates dihydropyrimidine dehydrogenase (DPD) in an NADPH-dependent manner. It enhances the efficacy of the chemotherapeutic agent and DPD substrate 5-fluorouracil in a P388 murine leukemia model when administered at a dose of 200 μmol/kg, increasing survival time.