A Phase 2, Single-Arm Study To Assess The Efficacy and Safety Of 72-Hour Continuous Intravenous Dosing Of ON 01910.Na Administered Once Every 2 Weeks in Myelodysplastic Syndrome Patients With Trisomy 8 or Classified as Intermediate-1, 2 or High Risk

Inclusion Criteria:

- > 18 years

- Diagnosis of MDS via bone marrow aspirate and biopsy according to WHO Criteria and
FAB Classification

- Anemia requiring transfusion support with at least one unit of packed red blood cells
per month for greater than or equal to 2 months or Hemoglobin < 10 g/dL OR
Thrombocytopenia (platelet count < 100,000/ul) OR Neutropenia (absolute neutrophil
count < 1,500/ul)

- Failed to respond to, relapsed following, or opted not to participate in bone marrow
transplantation

- Off all other treatments for MDS (including filgrastim (G-CSF) and erythropoietin)
for at least four weeks. As an exception, filgrastim (G-CSF) can be used before,
during and after the protocol treatment for patients with documented febrile
neutropenia (<500/ul)

- ECOG Performance Status 0, 1 or 2

- Adequate contraceptive [including prescription oral contraceptives (birth control
pills), contraceptive injections, intrauterine device (IUD), double-barrier method
(spermicidal jelly or foam with condoms or diaphragm), contraceptive patch, or
surgical sterilization] before entry and throughout the study for female patients of
reproductive potential

- Female patient with reproductive potential must have a negative serum beta-HCG
pregnancy test at screening

- Willing to adhere to the prohibitions and restrictions specified in this protocol

- Patient (or his/her legally authorized representative) must have signed an informed
consent document indicating that he/she understands the purpose of and procedures
required for the study and is willing to participate in the study

Exclusion Criteria:- Anemia due to factors other than MDS (including hemolysis or
gastrointestinal bleeding)

- Proliferative (WBC >= 12,000/mm^3) chronic myelomonocytic leukemia

- Any active malignancy within the past year except basal cell or squamous cell skin
cancer or carcinoma in situ of the cervix or breast

- History of HIV-1 seropositivity

- Uncontrolled intercurrent illness including, but not limited to symptomatic
congestive heart failure, unstable angina pectoris or cardiac arrhythmia

- Active infection not adequately responding to appropriate therapy.

- Total bilirubin > 1.5 mg/dL not related to hemolysis or Gilbert's disease, ALT or AST
> 2 X ULN

- Serum creatinine > 1.5 mg/dL or calculated creatinine clearance < 60 ml/min/1.73 m^2

- Ascites requiring active medical management including paracentesis, or hyponatremia
(defined as serum sodium value of <134 Meq/L).

- Women patients who are pregnant or lactating

- Male patients with female sexual partners who are unwilling to follow the strict
contraception requirements described in this protocol

- Major surgery without full recovery or major surgery within 3 weeks of ON 01910.Na
treatment start.

- Uncontrolled hypertension (defined as a systolic pressure >= 160 and/or a diastolic
pressure >= 110)

- New onset seizures (within 3 months prior to the first dose of ON 01910.Na) or poorly
controlled seizures

- Any concurrent investigational agent or chemotherapy, radiotherapy or immunotherapy

- Psychiatric illness/social situations that would limit the patient's ability to
tolerate and/or comply with study requirements