 For patients of the high-risk group, the administration of 2-chloro-2-deoxyadenosine 2-CDA will be integrated in the first phase of consolidation to achieve an even higher intensification. It could be shown that 2-CDA possesses good antileukemic activity in pediatric and adult AML. In a phase-II study it could also be demonstrated that 2-CDA has good effectiveness in combination with cytarabine. Results of phase-II studies conducted at St. Jude Childrens Hospital, Memphis, showed that 2-CDA has good effectiveness especially in children with monoblastic leukemias FAB M4M5. Consequently, this intensification for high-risk patients, who present in more than half of the cases with monoblastic leukemias FAB M45, may allow further improvement of therapy for this cohort. The pilot study AML-BFM 2002P confirmed that the study design was practicable without increasing significantly the risk of higher toxicity. However, median duration of aplasia was significantly prolonged in comparison to that of the AI cytarabine, idarubicin-block. Objective two of this study is to determine by randomisation if an improvement of efficiency is possible. 