[BOF-A1 and BOF-A2, new 5-FU degradation-inhibitory agents]

2, 6-Dihydroxy-3-cyano pyridine (CNDP) was found from the study of inhibitory effects of pyrimidine and pyridine derivatives on 5-FU degradation catalyzed by dihydrouracil dehydrogenase. CNDP, a new inhibitor on 5-FU degradation was 300 times more effective than uracil. Co-administration of an equi-molar CNDP with some fluorinated pyrimidine preparations potentiated their antitumor activity. Tegafur (FT-207) and EM-FU in combination with CNDP were found most effective. This potentiation was exhibited not only to 5-FU derivatives but also to FdUrd and its derivatives. BOF-A1 and BOF-A2, new compounds combined with CNDP were markedly active against mouse sarcoma 180 and rat Yoshida sarcoma.