Inclusion Criteria:

- Age 18-65 years.

- WHO PS grade 0-2 (Appendix B) or Karnofsky > 70.

- AML according to the new WHO criteria, i.e., % of BM blasts ≥ 20%. NB. this % should
be assessed on a BM aspiration or on a BM biopsy

- All FAB subtypes except M3.

- CD33 positivity (> 20%). It is mandatory to perform an immunotyping of the BM blasts
in particular the determination of CD33 positivity, which will be used as a inclusion
factor.

- Previously untreated (except ≤ 14 days of Hydroxyurea) primary or secondary AML
(including AML after MDS).

- Adequate renal and liver function, i.e., creatinine < 2 mg/dl and bilirubin, ALT/AST
≤ 3 times the upper limit of normal.

- Written informed consent

Exclusion Criteria:

- Blast crisis of chronic myeloid leukemia.

- AML supervening after other myeloproliferative diseases.

- AML de novo or secondary previously pretreated.

- Concomitant malignant disease.

- Active central nervous system (CNS) leukemia.

- Active uncontrolled infection [NB severe systemic infection should be excluded].

- Concomitant severe cardiovascular disease, i.e., arrhythmias requiring chronic
treatment, congestive heart failure or symptomatic ischemic heart disease.

- Cardiac ejection fraction of 50% or less.

- Severe pulmonary dysfunction (CTC grade 3-4).

- Severe concomitant neurological or psychiatric disease.

- History of alcohol abuse.

- HIV positivity.

- Pregnancy.

- Man and woman not agreeing to the adequate contraceptive precautions during study
period and for at last 24 months after stop of therapy.

- Any psychological, familiar, sociological or geographical condition potentially
hampering compliance with the study protocol and follow-up schedule.