This is a phase I/II, single-arm, open-label, study to establish the recommended dose and activity of AEG35156 administered as a daily x3 two-hour infusion prior to reinduction chemotherapy with idarubicin and ara-C followed by weekly two-hour AEG35156 infusions. Subjects eligible for study entry must have confirmed diagnosis of AML in first relapse after an initial CR that lasted less than 6 months or primary refractory AML. Fixed dose of idarubicin and ara-C will be given, plus one of eight doses of AEG35156: 12, 24, 48, 75, 110, 165, 250 and 350mg/m2. A maximum of 54 patients will be treated in cohorts of size 3, starting at 12mg/m2, and not skipping any untried dose level when escalating. Following dose escalation, approximately 20 patients will be treated at the best acceptable dose as determined by the method of Thall and Cook (2004).