Comparison of the antitumor activity of DTIC and 1-p-(3,3-dimethyl-1-triazeno) benzoic acid potassium salt on murine transplantable tumors and their hematological toxicity

This study describes a comparison of 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) and imidazole-4-carboxamide,5-(3,3-dimethyl-1-triazeno) (DTIC) with reference to antitumor activity on different murine tumors and hematological toxicity. DM-COOK appeared comparably or slightly more effective in L1210, P388, and M5 tumors in the mouse. However, when the treatment of mice bearing M5 with DM-COOK was combined with surgical removal of the primary tumor, the host's life-span was highly significantly prolonged. The two drugs showed similar activity in an M5 variant selected for resistance to cyclophosphamide. In L1210 Ha, a leukemia that is spontaneously resistant to DTIC, DM-COOK was not effective. Both DM-COOK and DTIC caused transient leukopenia with a maximum WBC fall of 57% and 71% compared with control values. DM-COOK's greater chemical stability might be an advantage, as the decomposition of DTIC is thought to lead to products responsible for some toxic effects in humans. Like other phenyldimethyltriazenes DM-COOK, is a good candidate for clinical trials because its water solubility eliminates formulation problems.