 This trial is an open-label, multi-centre, dose-escalation Phase III study to evaluate safety, explore efficacy, pharmacodynamics, and pharmacokinetics of the combination of PXD101 with idarubicin administered in two different schedules in patients with AML. The PXD101 plus idarubicin treatment will be repeated at suitable intervals target is every 3 weeks for schedule A and every 2 weeks for schedule B depending upon toxicities or disease progression. Safety and efficacy assessments will be performed at every cycle. 