Assessment of lethal and cytostatic effects of alkylnitrosoureas on the cells of experimental tumors.

The action of a number of active anticancer agents belonging to the alkylnitrosoureas (MNU, DMNU, ADEKO, BCNU, CCMU, MeCCNU), as well as the effectiveness of a combined use of DMMU and ADEKO with cyclophosphamide was assessed on experimental tumors transplanted by inocula of different size. A mathematical model of the connection between survival of tumor-bearing animals with the kinetics of tumor growth was proposed to analyze the treatment effect. The contribution of lethal and cytostatic factors to the resultant effect of the drugs was evaluated. A combination of DMNU and cyclophosphamide was found to possess an additive effect. The synergism of the therapeutic action shown in a combined application of ADEKO and cyclophosphamide was stipulated by the potentiation of the lethal effect of these drugs on tumor cells.