[Early phase II study of Idarubicin, a new anthracycline anticancer drug, in acute leukemia. Idarubicin Study Group].

An early phase II study of Idarubicin was performed in patients with acute leukemia. The dosages administered were 10 mg/m2, 12 mg/m2, or 15 mg/m2 by iv bolus, once daily for 3 consecutive days. The treatment was given to 47 patients who were in relapse or whose diseases had been refractory to remission induction therapy. Of the 47 patients, 35 were evaluable for response. The patients who showed a response (complete or partial remission) were 9 of 14 patients (64.3%) in the 10 mg/m2 group, 1 of 12 patients (8.3%) in the 12 mg/m2 group, and 3 of 9 patients (33.3%) in the 15 mg/m2 group, respectively. Remissions were achieved in 10 of 23 (43.5%) patients with acute myelogenous leukemia, and in 3 of 6 (50.0%) of those with chronic myelogenous leukemia in blast crisis. However, no remission was achieved in 6 patients with acute lymphocytic leukemia. As for patients who had received prior anthracycline therapy, remissions were achieved in 11 of 29 patients (37.9%), and so clinical cross resistance between idarubicin and other anthracyclines was thought to be partial. The principal adverse effects were gastrointestinal symptoms, alopecia, fever and infection. In the 15 mg/m2 group, there was an increased number of adverse events of WHO's grade 3 or over. The result indicated that Idarubicin is a useful drug for the treatment of acute leukemia, and the clinical optimal dosage estimated was either 10 mg/m2 or 12 mg/m2 once daily for 3 consecutive days.