Safety and Tolerability of Oral Clofarabine in Intermediate to High Risk Myelodysplastic Patients

Inclusion Criteria: * Provide signed written informed consent. * Patients with MDS must have IPSS score that falls in the intermediate or high risk disease (intermediate 1 will have to be transfusion dependent). * Patients may have received up to two prior therapies for MDS including one hypomethylating agent and/or a biologic agent (biologic agents include GM-CSF or equivalent, danazol or equivalent, Sunitinib, Revlimid, ATG, or a vaccine). * Age ≥ 18 * Have adequate renal and hepatic functions as indicated by the following laboratory values: * Serum creatinine ≤ 1 mg/dL; if serum creatinine \>l mg/dL, then the estimated glomerular filtration rate (GFR) must be \>50 mL/min/1.73 m2 as calculated by the Modification of Diet in Renal Disease equation. * Serum bilirubin ≤1.5 mg/dL x upper limit of normal (ULN) * Aspartate transaminase (AST)/alanine transaminase (ALT) ≤2.5 x ULN * Alkaline phosphatase ≤2.5 x ULN * Capable of understanding the investigational nature, potential risks and benefits of the study, and able to provide valid informed consent. * Female patients of childbearing potential must have a negative serum pregnancy test within 2 weeks prior to enrollment. * Male and female patients must use an effective contraceptive method during the study and for a minimum of 6 months after study treatment. Exclusion Criteria: * Have any other severe concurrent disease, or have a history of serious organ dysfunction or disease involving the heart, kidney, liver, or other organ system that may place the patient at undue risk to undergo treatment. * Active CNS disease * Patients with a systemic fungal, bacterial, viral, or other infection not controlled (defined as exhibiting ongoing signs/symptoms related to the infection and without improvement, despite appropriate antibiotics or other treatment). * Pregnant or lactating patients. * Any significant concurrent disease, illness, or psychiatric disorder that would compromise patient safety or compliance, interfere with consent, study participation, follow up, or interpretation of study results. * Have had any prior treatment with clofarabine * Have had a diagnosis of another malignancy, unless the patient has been disease free for at least 3 years following the completion of curative intent therapy, with the following exceptions: * Patients with treated non-melanoma skin cancer, in situ carcinoma, or cervical intraepithelial neoplasia, regardless of the disease-free duration, are eligible for this study if definitive treatment for the condition has been completed. * Patients with organ-confined prostate cancer with no evidence of recurrent or progressive disease based on prostate-specific antigen (PSA values are also eligible for this study if hormonal therapy has been initiated or a radical prostatectomy has been performed. * Have prior positive test for the Human Immunodeficiency Virus (HN). * Have prior positive test for the Human Immunodeficiency Virus (HN). * Have currently active gastrointestinal disease, or prior surgery that may affect the ability of the patient to absorb oral clofarabine. * Patients taking proton pump inhibitors such as omeprazole (Prilosec®), lansoprazole (Prevacid®), or esomeprazole (Nexium®). Those who cannot stop taking these drugs should be switched to H2 blockers such as famotidine (Pepcid®)or ranitidine (Zantac®). * Patients taking alternative medicines (such as herbal or botanical) are not permitted.