A Pharmacokinetic And Pharmacodynamic Study Of Oral Lenalidomide (Revlimid) In Subjects With Low- Or Intermediate-1-Risk Myelodysplastic Syndromes

Inclusion Criteria: 1. Must understand and voluntarily sign an informed consent form. 2. Age ≥18 years at the time of signing the informed consent form. 3. Must be able to adhere to the study visit schedule and other protocol requirements. 4. Documented diagnosis of MDS that meets International Prognostic Scoring System (IPSS) criteria for Low- to Intermediate-1-risk disease. •Must have a diagnosis of low- or intermediate- risk MDS without a del 5q chromosomal abnormality (patients taking 15 mg starting dose only). 5. Must be able to provide adequate bone marrow (BM) aspirate and biopsy specimens for histopathological analysis and standard cytogenetic analysis during the screening procedure. 6. Red blood cell (RBC) transfusion-dependent anemia defined as having received ≥4 transfusions of RBCs within 56 days of randomization or symptomatic anemia (hemoglobin \< 9.0 g/dl). 7. Failed prior treatment with recombinant human erythropoietin (rhu-EPO) (≥ 30,000 U/week x 6) or serum erythropoietin (EPO) concentration ≥500 mU/ml (hemoglobin \< 9.0 g/dl). 8. Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2. 9. Females of childbearing potential (FCBP) must agree to use two reliable forms of contraception simultaneously or to practice complete abstinence from heterosexual intercourse 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. The two methods of reliable contraception must include one highly effective method (i.e. intrauterine device \[IUD\], hormonal \[birth control pills, injections, or implants\], tubal ligation, partner's vasectomy) and one additional effective (barrier) method (i.e. latex condom, diaphragm, cervical cap). FCBP must be referred to a qualified provider of contraceptive methods, if needed. Exclusion Criteria: 1. Pregnant or lactating females. 2. Prior therapy with lenalidomide. 3. Proliferative white blood cell (WBC) ≥12,000/µL) chronic myelomonocytic leukemia (CMML). 4. MDS secondary to treatment with radiotherapy, chemotherapy, and/or immunotherapy for malignant or autoimmune diseases. 5. Any of the following lab abnormalities: * Absolute neutrophil count (ANC) \<500 cells/µL (0.5 x 10\^9/L) * Platelet count \<50,000/µL (50 x 10\^9/L) * Serum creatinine \> upper limit of normal (ULN) * Serum glutamic oxaloacetic transaminase/aspartate transaminase (SGOT/AST) or serum glutamic pyruvic transaminase/alanine transaminase (SGPT/ALT) \>2.0 x ULN * Serum total bilirubin \>2.0 mg/dL (34 µmol/L) 6. Prior ≥grade-2 National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) allergic reaction to thalidomide. 7. Prior desquamating (blistering) rash while taking thalidomide. 8. Patients 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. 10. 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. 11. 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 ≥3 years. 12. Any serious medical condition or psychiatric illness that will prevent the patient from signing the informed consent form or will place the subject at unacceptable risk if he/she participates in the study. 13. Known human immunodeficiency virus (HIV-1) positivity.