Effects of T-activin and vitamin E on toxicity and antitumor activity of cyclophosphamide.

We studied the effect of combination treatment with T-activin and vitamin E on acute toxicity and antitumor activity of cyclophosphamide in mice. Combined administration of these preparations 1.37-fold increased the maximum permissible dose of cyclophosphamide without affecting its LD(50)and delayed mouse death from cyclophosphamide toxicity. Most mice died only 3 days after combination treatment with the test preparations and cyclophosphamide in doses of LD(16)-LD(84). The second peak of death from hematologic toxicity of cyclophosphamide was absent under these conditions. T-activin and vitamin E did not abolish the antitumor effect of cyclophosphamide on mice with subcutaneously implanted P-388 lympholeukemia. Tumor growth was suppressed by 100%.