Characteristics of prognosis and response to an imidazole carboxamide in malignant melanoma

In a prospective randomized study of 155 patients, dimethyltriazeno imidazole carboxamide, 2.0 or 4.5 mg. per kilogram given for 10 successive daily intravenous doses, resulted in ob;ective response in 28 per cent of 115 evaluable patients. The 2.0 mg. schedule produced a significantly greater rate and duration of response (p ≤ 0.05) than did the 4.5 mg. schedule. In half of the responding patients the response exceeded 6 months in duration. Urinary melanogens, detected by a qualitative test in 29 per cent of patients tested, suggested widespread disease but were not helpful in diagnosing clinically occult recurrent disease. Toxicity was somewhat greater on the 4.5 mg. regimen, but in general it was mild; there were no drug deaths. The drug, which has some interesting and unusual dose‐toxicity‐response relationships, appears to be the most effective chemotherapeutic agent for treatment of malignant melanoma.