ANTITUMOR ACTIVITY OF CYCLOCYTIDINE IN A VARIETY OF TUMORS

抄録

The antitumor activity of cyclocytidine was examined in a variety of tumors. Cyclocytidine was active against adenocarcinoma-755, Nakahara-Fukuoka sarcoma, ascites sarcoma-180, Ehrlich ascites carcinoma, L-1210 leukemia, and C-1498 leukemia. Cures (60-day survivors) were observed at 500mg/kg/day×5 or more of the compound in the L-1210 system and therapeutic ratio was as high as 50, though that of other known antitumor agents tested, including 1-β-D-arabinofuranosylcytosine (Ara-c), was less than 12. Therapeutic index of cyclocytidine in the solid and ascites tumors was always greater than that of Ara-c. Cumulative toxicity of cyclocytidine was surprisingly low and LD₁₀ was 790mg/kg/day×5, whereas that of Ara-c was 82mg/kg/day×5. Cyclocytidine appears therefore to have advantages over Ara-c for clinical use.