Effect of imidazole-4-carboxamide, 5-(3,3-dimethyl-1-triazeno) on immunity in patients with malignant melanoma.

Imidazole-4-carboxamide, 5-(3,3-dimethyl-l-triazeno), NSC 45388 (DTIC), was administered for 5 consecutive days as a rapid 150-mg/sq m or 250-mg/sq m infusion to 13 patients with melanoma. DTIC did not interfere with induc tion of a cellular immune (delayed hypersensitivity) re sponse to dinitrochlorobenzene in 7 of 12 patients tested or with established delayed hypersensitivity reactions in 8 of 8 patients. The 5 nonresponders to dinitrochlorobenzene were unable to manifest a cellular immune response to skin test antigens even before treatment with DTIC. DTIC did not suppress the primary humoral response to Vi antigen in 7 of 12 patients. The secondary response to tetanus toxoid was normal in 5 of 7 patients. These results indicate that DTIC at these dosage schedules was only moderately immunosuppressive and inhibited humoral immune responses slightly more than the cellular responses tested.