We are evaluating the incidence of significant hematological response, according to IWG criteria including CR, PR or, major HI, (HI-E, Hl-N,or Hl- P), and cytogenetic response of patients diagnosed with intermediate-2 or high-risk (International Prognostic Scoring System [IPSS]) MDS with a deletion (del) 5q[31]

Subjects meeting all inclusion and exclusion criteria will receive lenalidomide

lenalidomide will be administered at 10 mg (two 5 mg capsules) once daily on Days 1-21, every 4 weeks.

Bone marrow aspirate (baseline and during the course of the study at week 8, 16, 32, 52 and when clinically indicated/for assessment of disease progression) evaluations

Subjects may participate in the study for up to 52 weeks ( in patients still responding after 52 weeks, the drug wil continue to be supplied).

Inclusion Criteria:

• Age > 18 years at the time of signing the informed consent form
• MDS with IPSS scores Int-2 or high with deletion 5q(31)
• Prior thalidomide allowed
• Documented diagnosis of MDS (RA, RARS, RAEB, RAEB-T and CMML with WBC < 13,000/mm3 according to FAB classification) that meets IPSS criteria for intermediate-2 or high-risk disease and has an associated del 5q[31] (the deleted chromosomal region must include 5q[31]), with or without additional cytogenetic abnormalities

Exclusion Criteria:

• Pregnant or lactating females
• Prior therapy with lenalidomide
• MDS with IPSS scores low or Int-1
• Clinical neuropathy of greater than grade 2
• Proliferative (WBC ≥ 13,000/mL) chronic myelomonocytic leukemia (CMML)
• Recombinant human erythropoietin (rHuEPO) therapy received within 28 days
• Use of androgens other than for treating hypogonadism