This open label phase-II trial evaluates hematological response of an additional treatment with 5-Azacitidine to common DLI in patients with MDS or AML relapsing after allogeneic stem cell transplantation.

Relapse after allogeneic stem cell transplantation is a major problem in patients with poor prognosis AML or MDS. Donor lymphocyte infusions alone re-induce remission in a minority of these patients, which may be the result of poor differentiation of the leukemic cells. The study drug 5-Aza is effective in AML and MDS.In addition to direct cytotoxicity, it alters gene expression and induces differentiation of leukemic blast cells. Furthermore, DNA-demethylating treatment results in an induction of transcription and cell surface expression of formerly unexpressed KIRs (killer Ig-like receptors) in NK cells, which are involved in the specific recognition of leukemic target cells and who are able to generate a specific graft-versus leukemia effect. The increased expression of MHC class I and II molecules on the surface of the recipient's leukemic cells and the de novo expression of formerly silenced KIR genes in donor NK cells due to treatment with 5-Aza may result in an increased susceptibility of myeloid leukemic cells to the allogeneic graft versus leukemia effect. Therefore, the graft-versus leukemia effect by donor lymphocyte infusions and NK cells from the original donor may be supported by additional therapy with 5-Azacitidine.

Inclusion Criteria:

- Primary and secondary MDS, AML after MDS, and de novo AML relapsing after allogeneic stem cell transplantation

• Eligibility for Donor Lymphocyte Infusions
• Performance status according to the WHO scale: 0, 1 or 2.
• Adequate renal and liver function: bilirubin < 1.5 times the upper limit of normal and a GFR > 50 ml/min
• Absence of severe cardiovascular disease, i.e., arrhythmias requiring chronic treatment, congestive heart failure (NYHA Class III or IV) or symptomatic ischemic heart disease, where New-York Heart Association (NYHA)
• HIV negative and HBs-Ag negative.
• Absence of active uncontrolled infection (Septicaemia).
• No prior history or current evidence of central nervous system and psychiatric disorders requiring hospitalization.
• Age at least 18 years.
• Negative pregnancy test for women with reproductive potential.
• Signed written informed consent must be given according to national/local regulations.

Exclusion Criteria:

- Have malignant hepatic tumors.

• Severe liver dysfunction CHILD B and C.
• Renal insufficiency with a GFR < 50 ml/min
• Radiation therapy, chemotherapy, or cytotoxic therapy, given to treat conditions other than MDS, AML or applied for conditioning prior allogeneic stemcell transplantation.
• Psychiatric illness that would prevent granting of informed consent.
• Treatment with androgenic hormones during the previous 14 days prior Day 1.
• Active viral infection with known human immunodeficiency virus (HIV) or viral Hepatitis B or C.
• Hypersensitivity to Mannitol or 5-Azacitidine.
• Treatment with other investigational drugs following relapse after allogeneic stemcell transplantation or ongoing adverse events from previous treatment with investigational drugs regardless of time period.