Study of 72-Hour Infusion of ON 01910.Na in Patients With MDS or AML

Inclusion Criteria:

* \> 18 years
* Diagnosis of MDS or AML via bone marrow aspirate and biopsy performed within 8 weeks prior to study entry according to WHO Criteria and FAB Classification. AML patients must be:

not eligible for standard chemotherapy, including newly diagnosed patients over 70 years; with relapsed or refractory AML; and, with AML secondary to prior cancer chemotherapy or evolving from a myeloproliferative/myelodysplastic syndrome.

* 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/µl) OR Neutropenia (absolute neutrophil count \< 1,500/µl)
* Failed to respond to, relapsed following, or opted not to participate in bone marrow transplantation
* Off all other treatments for MDS or AML (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/µl)
* 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 or AML (including hemolysis or gastrointestinal bleeding)
* Proliferative (WBC ≥ 12,000/mm3) 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 m2
* 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