This is a multicenter, multinational, non-randomized, non-controlled open-label phase II trial to evaluate the safety and efficacy of treosulfan in a combination regimen with fludarabine as conditioning therapy prior to allogeneic stem cell transplantation (SCT) in patients with AML.

The aim is to demonstrate a clinical benefit compared with historical data on intravenous busulfan (BusulfexTM, BusilvexTM), the only drug so far registered in the indication conditioning before allogeneic stem cell transplantation.

Inclusion Criteria:

• Patients with acute myeloid leukaemia (AML) according to WHO classification (> 20% myeloblasts in peripheral blood or bone marrow at initial diagnosis) with < 5% myeloblast in the bone marrow, indicated for allogeneic transplantation
• Availability of an HLA-identical sibling donor (MRD) or HLA-identical unrelated donor (MUD) HLA-identity defined by the following markers: A, B, DRB1, DQB1.
• Target graft size (unmanipulated)
• bone marrow: 2 - 10 x 106 CD34+ cells/kg BW recipient or > 2 x 108 nucleated cells/kg BW recipient or
• peripheral blood: 4 - 10 x 106 CD34+ cells/kg BW recipient
• Age > 18 and < 60 years
• Karnofsky Index > 80 %
• Adequate contraception in female patients of child-bearing potential
• Written informed consent

Exclusion Criteria:

• Therapy related secondary AML
• AML with t(8;21)(q22;q22) in CR1
• Acute promyelocytic leukaemia with t(15;17)(q22;q12) in CR1
• Secondary malignancies
• Previous allogeneic transplantation
• Severe concomitant illnesses / medical conditions (e.g. impaired respiratory and/or cardiac function)
• Known and manifested malignant involvement of the CNS
• Active infectious disease
• HIV- positivity or active hepatitis infection
• Impaired liver function (Bilirubin > upper normal limit; Transaminases > 3.0 x upper normal limit)
• Impaired renal function (Creatinine-clearance < 60 ml/min; Serum Creatinine > 1.5 x upper normal limit).
• Pleural effusion or ascites > 1.0 L
• Pregnancy or lactation
• Known hypersensitivity to treosulfan and/or fludarabine
• Participation in another experimental drug trial within 4 weeks before day -6
• Non-co-operative behaviour or non-compliance
• Psychiatric diseases or conditions that might impair the ability to give informed consent