Mitomycin C in the treatment of chronic myelogenous leukemia.

Studies made of the treatment with 66 courses of mitomycin C in 28 patients with chronic myelogenous leukemia are reported. The effect of mitomycin C was investigated according to the relation between drug and host factors, comparison with the effects of other agents, and drug resistance. Patients with less hematological and clinical symptoms responded better to mitomycin C therapy. The remission rate of cases treated intravenously with mitomycin C was 93.8% and of cases treated orally with mitomycin C was 72.0%. The remission rate of the total cases (intravenous and oral) treated with mitomycin C was 77.3%. The therapeutic effect of mitomycin C is considered to be equal or be somewhat superior to the effect of busulfan as a result of data on the occurrence of resistance, cross resistance, development of acute blastic crisis and life span. Busulfan was effective in patients resistant to mitomycin C, and mitomycin C did not clinically show cross resistance to alkylating agents. Two patients resist· ant to mitomycin C recovered the sensitivity to mitomycin C after treatment with busulfan or 6-mercaptopurine. Side effects were observed in 39.4% of 66 cases, but severe side effect causing suspension of mitomycin C was rare.