Experimental Treatment of Ehrlich Solid Tumor with S-339 Comparative Study of Various Doses and Administration Schedules

Abstract

In the antibiotic field, many antitumor substances have been isolated and some of them are now used in practice. A new antibiotic substance, S-339 was isolated in our laboratory from a soil streptomyces. Morphological characteristics of the strain and the properties of the substance will be published in a separate paper. The cytomorphological changes of S-339 in Yoshida sarcoma were already reported¹⁾. We are reporting here the results obtained with S-339 in the experimental treatment of Ehrlich subcutaneous solid carcinoma.

In the consecutive daily administration of antitumor antibiotics, as usually performed, the tolerated dose is usually limited by the toxic reaction of the substance on the host animal and the chronic toxic dose is not so higher than that of the acute toxic dose for this kind of antitumor substances. These observation have led us to carry out a series of experiments with the purpose of finding out administration schedules which would produce the highest possible antitumor activity with least toxic side effect. Thus, the substance S-339 was administered intravenously, using various administration schedules, to mice bearing Ehrlich solid tumor, and the results were compared.