Inclusion Criteria:

- Must understand and voluntarily sign an informed consent form.

- Age ≥ 20 years at the time of signing the informed consent form.

- Must be able to adhere to the study visit schedule and other protocol requirements.

- Diagnosis of Myelodysplastic Syndrome (MDS) that meets International Prognostic
Scoring System (IPSS) criteria for low- or intermediate-1-risk disease associated
with a deletion 5(q31-33) abnormality

- Symptomatic anemia secondary to MDS defined as:Untransfused Hb level < 10.0 g/dL
and a Functional Assessment of Cancer Therapy (FACT)-anemia subscale score of ≤ 74
or Transfusion dependent anemia

Exclusion Criteria:

- Pregnant or lactating females.

- Any condition, including the presence of laboratory abnormalities, which places the
subject at unacceptable risk if he/she were to participate in the study.

- Prior therapy with lenalidomide.

- Patients with any of the following laboratory abnormalities within 14 days of
starting study drug: Absolute Neutrophil Count (ANC) < 750 cells/μL (0.75 x
10^9/L) Platelet count < 50,000/μL (50x10^9/L) Serum creatinine > 2.5 mg/dL Aspartate
Aminotransferase (AST) or Alanine Aminotransferase (ALT) > 3.0 x Upper Limit of
Normal (ULN)