Cordycepin, a nucleoside isolated from cultures of the mold Cordyceps militaris, has been demonstrated to increase the survival time of mice bearing the Ehrlich mouse ascites tumor. In all these studies the drug was administered daily for a 7-day period. When drug inoculations were started the same day as tumor inoculations, inhibition of tumor growth was noted at levels of from 15 to 200 mg/kg body weight. When the initial administration of drug was begun on animals in which the tumor was 5 days old, a dosage of 150 mg/kg body weight resulted in a significantly increased survival time.
A preliminary report of this work was presented before the American Society of Biological Chemists, April, 1960 (6). This work was supported in part from grants from the National Science Foundation, NSF G-6423; and the American Cancer Society Institutional Research Grant 44-F.