The primary objective has already been answered with the number of recruited patients.

The hypothesis of this study is that 5-aza and lenalidomide act synergistically in MDS and AML patients with chromosomal abnormalities involving monosomy 5 or del5q. Therefore, this phase I study will investigate the maximum tolerated dose (MTD) of lenalidomide in combination with a fixed dose of 5-aza in this patient population.

Cytogenetics are the main predictors of outcome in patients with AML. In fact, a monosomy 5 or del (5q) as single aberration are poor prognostic markers. Overall, the complete response rate for conventionally treated patients with newly-diagnosed AML with chromosome 5 abnormalities is about 31% to 37 % and all patients rapidly relapse if not rescued by allogeneic HSCT. The situation is almost similar in patients with high-risk MDS.Vidaza® has been shown in clinical trials to achieve remission rates in about 29% (CR+PR) of the patients while a total of 49% achieve improvement of blood counts.Revlimid® is also able to achieve complete remissions in advanced MDS and even overt leukemia with or without chromosome 5 abnormalities. Nevertheless, response rates are lower compared to low-risk MDS (IPSS Low/INT-1). Therefore, Revlimid® seems to be too weak as a single agent, but a promising compound for a combination therapy.

Inclusion Criteria:

• Understand and voluntarily sign an informed consent form.
• Age >=18 years at the time of signing the informed consent form.
• Able to adhere to the study visit schedule and other protocol requirements.
• Relapsed or refractory AML (>30% blasts, FAB classification)with karyotype abnormalities involving monosomy 5 or del(5q) or MDS and t-MDS INT-2 or HIGH according to IPSS classification with karyotype abnormalities involving monosomy 5 or del(5q) either previously treated or untreated
• Not eligible for an immediate allogeneic HSCT (due to donor unavailability)
• All previous MDS or AML specific therapy with exception of corticosteroids not exceeding doses of 10mg/day prednisone must have been discontinued at least 1 week prior to study enrollment.
• Non-hematological toxicity (except alopecia) resulting from previous treatment must be resolved to WHO CTC Grade ≤ 2.
• ECOG performance status of < 3 at study entry.
• Laboratory test results within these ranges:Serum creatinine <= 2.0 mg/dL, Total bilirubin <= 3 x ULN, AST (SGOT) and ALT (SGPT) <= 3 x ULN
• Females of childbearing potential must agree to use a reliable form of contraception or to practice complete abstinence from heterosexual intercourse during the following time periods related to this study: 1) for at least 28 days before starting study drug; 2) while participating in the study; and 3) for at least 28 days after discontinuation from the study.

Exclusion Criteria:

• Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent form.
• Pregnant or breast feeding females. (Lactating females must agree not to breast feed while on study).
• Any condition, including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study or confounds the ability to interpret data from the study.
• Known hypersensitivity to thalidomide, lenalidomide, 5-azacitidine or mannitol.
• Myocardial infarction within 6 months before study entry, New York Heart Association Class III or IV heart failure, uncontrolled angina or severe uncontrolled ventricular arrhythmias.
• The development of erythema nodosum if characterized by a desquamating rash while taking thalidomide or similar drugs.
• Uncontrolled lung disease.
• Known positive for HIV or acute infectious hepatitis, type A, B or C.
• Participation in another clinical study in the 4 weeks prior to enrollment or during this study.