Antitumor activity of a new camptothecin derivative, SN-22, against various murine tumors

The antitumor activity of a new camptothecin derivative, SN-22, was evaluated by using various murine tumors. SN-22 showed strong activity against the ascites tumors Ehrlich carcinoma, MM46, CCM, L1210, L5178Y, P388, Meth A, and B16 melanoma. In particular, the maximum increase in life span values for Ehrlich, MM46 and CCM were as high as 253-606% and many mice were cured of these tumors. The effect of SN-22 against solid tumors was also determined. The inhibition ratios were higher than 70% for MM46 and L5178Y. The LD50 of SN-22 in ICR mice was about 1.5 times that of the parent camptothecin.