 Elacytarabine CP-4055 is a pro-drug of ara-C currently used in the treatment of patients with acute myeloid leukaemia. Patients with nucleoside transporter deficiency hENT1 seem to have less benefit from cytarabine compared to those with a high expression of the transporter. Preclinical studies indicate that elacytarabine is independent of this transporter. Therefore, patients with low expression of hENT1 and treated with elacytarabine are anticipated to have a better outcome compared to patients treated with ara-C. The main objective of this study is to assess the biological activity of elacytarabine in combination with idarubicin in patients with acute myeloid leukaemia. In addition, the correlation between hENT1 human equilibrative nucleoside transporter 1 and overall survival will be studied. Patients will be treated with elacytarabine plus idarubicin independent of their hENT1 status. Determination of the patients hENT1 expression level will be done retrospectively. This study will also explore the safety profile of elacytarabine in combination with idarubicin. 