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.