Treatment of Imminent Haematological Relapse in Patients With AML and MDS Following Allogeneic Stem Cell Transplantation With 5-azacitidine (Vidaza®)

Inclusion Criteria:

Screening phase:

* Age \> 18 years
* Patients with CD34+ AML or MDS post-allogeneic HSCT
* Written patient consent after consultation

Treatment phase

* AML/MDS: donor chimerism \< 80% in the CD34+ subpopulation following allogeneic HSCT in patients with CD34+ AML or MDS, but with no haematological relapse (blasts \< 5% in bone marrow)
* Leukocytes \> 3 Gpt/l and platelets \> 75 Gpt/l (transfusion-independent)

Exclusion Criteria:

* Known intolerance to 5-azacitidine or mannitol
* Uncontrollable infectious disease
* Patients with active hepatitis B or C or HIV infection
* Severe hepatic function impairment (ASAT and ALAT may not be above three times the normal value) or hepatic cirrhosis, or malignant hepatic tumour
* Renal function impairment (creatinine \> twice the normal value, creatinine clearance \< 50 ml/min)
* Pregnancy or lactation
* Women of childbearing age, except for those who meet the following criteria:
* postmenopausal (12 months natural amenorrhoea)
* postoperative (6 weeks after bilateral ovarectomy with or without hysterectomy)
* regular and correct use of a contraceptive method with an error rate \< 1% per year (e.g. implants, depot injections, combined oral contraceptives, intrauterine device - IUD, whereby hormonal coils with a Pearl Index of \< 1% are safer than copper coils)
* sexual abstinence
* Partner vasectomy
* Men who do not use one of the following for contraception:
* sexual abstinence
* post vasectomy
* condoms
* Participation of the patient in a drug trial outside the indication of allogeneic transplantation up to four weeks before study initiation
* Addictive or other illnesses that prevent the person concerned from comprehending the nature and impact, as well as potentical consequences of the clinical trial
* Evidence that the patient may intentionally not comply with the protocol, e.g. lack of cooperation With the exception of a known allergic reaction or intolerance to 5-azacitidine, these criteria do not apply to the screening phase.