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.