Phase I study of idarubicin dose escalation for remission induction therapy in acute myeloid leukemia

The maximum tolerated dose (MTD) of idarubicin should be reevaluated in the treatment of acute myeloid leukemia (AML) in the era of granulocyte colony-stimulating factor and better supportive care. We conducted a phase I study to investigate the safety of escalating doses of idarubicin in combination with cytarabine 100 mg/m(2)/day for seven days for previously untreated AML. The starting dose of idarubicin was 12 mg/m(2)/day for three days with dose escalations by 3 mg/m(2)/day up to 18 mg/m(2)/day. The study design was adopted from traditional 3 + 3 design for phase I cancer clinical trials. The grade 4 hematologic toxicities were observed at all dose levels; however, these toxicities did not meet the criteria of the hematologic dose-limiting toxicities as defined in this study. There were no instances of grade 4 non-hematologic toxicities at any dose levels. The MTD of idarubicin was not reached in this trial.