Inclusion Criteria:

• Must understand and voluntarily sign an informed consent form.
• Age greater than or equal to 18 years at the time of signing the informed consent form.
• Must be able to adhere to the study visit schedule and other protocol requirements.
• Documented diagnosis of MDS that meets International Prognostic Scoring System (IPSS) criteria for Low- to Intermediate-1-risk disease.
• Subjects must be able to provide adequate BM aspirate and biopsy specimens for histopathological analysis and standard cytogenetic analysis during the screening procedure.
• RBC transfusion-dependent anemia defined as having received 4 transfusions of RBCs within 56 days of randomization or symptomatic anemia (Hgb< 9.0 g/dl).
• Failed prior treatment with rhu-EPO (> 30,000 U/wk x 6) or serum EPO concentration > 500 mU/ml (Hgb < 9.0 g/dl).
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2.
• Women of childbearing potential (WCBP)† must have a negative serum or urine pregnancy test within 7 days of starting study drug. In addition, sexually active WCBP must agree to use adequate contraceptive methods (oral, injectable, or implantable hormonal contraceptive; tubal ligation; intra-uterine device; barrier contraceptive with spermicide; or vasectomized partner) while on study drug. WCBP must agree to have pregnancy tests every 4 weeks while on study drug.

Exclusion Criteria:

• Pregnant or lactating females.
• Prior therapy with CC-5013.
• Proliferative (WBC 12,000/L) chronic myelomonocytic leukemia (CMML).
• MDS secondary to treatment with radiotherapy, chemotherapy, and/or immunotherapy for malignant or autoimmune diseases.

• Any of the following lab abnormalities:

  1. Absolute neutrophil count (ANC) <500 cells/L (0.5 x 109/L)
  2. Platelet count <50,000/L (50 x 109/L)
  3. Serum creatinine > upper limit of normal (ULN)
  4. Serum SGOT/AST or SGPT/ALT >2.0 x ULN
  5. Serum total bilirubin >2.0 mg/dL (34 mol/L)
  6. Prior  grade-2 NCI CTC allergic reaction to thalidomide.
  7. Prior desquamating (blistering) rash while taking thalidomide.
  8. Subjects with  grade-2 neuropathy.
  9. Clinically significant anemia due to factors such as iron, B12 or folate deficiencies, autoimmune or hereditary hemolysis or gastrointestinal bleeding.
• Use of cytotoxic chemotherapeutic agents, erythropoietin, or experimental agents (agents that are not commercially available) for the treatment of MDS within 28 days of the first day of study drug treatment.
• Prior history of malignancy other than MDS (except basal cell or squamous cell carcinoma or carcinoma in situ of the cervix or breast) unless the subject has been free of disease for greater than or equal to 3 years.
• Any serious medical condition or psychiatric illness that will prevent the subject from signing the informed consent form or will place the subject at unacceptable risk if he/she participates in the study.
• Known HIV-1 positivity.