Inclusion Criteria:

• Male or female patients older than 60 years of age
• Patient with confirmed AML (except for APL) according to the WHO definition who relapsed after or are refractory to prior chemotherapy
• Leukocyte count <= 25,000 /mcl (25 x 10e9/Liter)
• Patient not eligible for intensive treatment options
• Life expectancy >= 2 months
• Eastern co-operative oncology group performance score of 2 or less
• Signed written informed consent consistent with international conference on harmonisation - good clinical practice (ICH-GCP) and local legislation

Exclusion Criteria:

• Patient with acute promyelocytic leukaemia (APL, AML of the French-American British (FAB) classification subtype M3)
• Hypersensitivity to the trial drug or the excipients
• Secondary malignancy requiring therapy
• Known central nervous system involvement
• Aspartate amino transferase (AST) or alanine amino transferase (ALT) greater than 2.5 times the upper limit of normal, or AST or ALT greater than 5 times the upper limit of normal in case of known liver involvement
• Bilirubin greater than 1.5 mg/dl (> 26 mcmol/l, SI unit equivalent)
• Serum creatinine greater than 2.0 mg/dl
• Concomitant intercurrent illness, which would compromise the evaluation of efficacy or safety of the trial drug, e.g. active severe infection, unstable angina pectoris or cardiac arrhythmia
• Psychiatric illness or social situation that would limit compliance with trial requirements
• Concomitant therapy, which is considered relevant for the evaluation of the efficacy or safety of the trial drug
• Chemotherapy (except hydroxyurea) or immunotherapy or treatment with any other investigational drug within the past four weeks prior to treatment with the trial drug
• Persistence of toxicities of prior anti-leukaemia therapies which are deemed to be clinically relevant
• Patients who are sexually active and unwilling to use a medically acceptable method of contraception during the trial (hormonal contraception, intrauterine device, condom with spermicide, etc.)
• Patient unable to comply with the protocol