Randomized Study of ON 01910.Na in Refractory Myelodysplastic Syndrome Patients With Excess Blasts

Inclusion Criteria:

* MDS diagnosis confirmed within 6 weeks prior to entry according to WHO or FAB classification
* MDS classified as follows, according to WHO and FAB classification:

  * RAEB-1 (5% - 9% BM blasts)
  * RAEB-2 (10% - 19% BM blasts)
  * CMML (10% - 20% BM blasts) and WBC \< 13,000/μL
  * RAEB-t (20% - 30% BM blasts), with following criteria:
  * o WBC \< 25 x 10E9/L at entry
  * o Stable WBC at least 4 weeks prior to entry and not requiring intervention for WBC control with hydroxyurea, chemotherapy, or leukopheresis.
* At least one cytopenia (ANC \< 1800/µL or platelet count \< 100,000/µL or hemoglobin \<10 g/dL)
* Progression according to 2006 International Working Group (IWG) criteria any time after start of azacitidine or decitabine during past 2 years; or failure to achieve complete or partial response or hematological improvement (according to 2006 IWG) after at least six 4-week cycles of azacitidine or four 6-week cycles of decitabine during past 2 years; or relapse after initial complete or partial response or hematological improvement (according to 2006 IWG criteria) observed after at least six 4-week cycles of azacitidine or four 6-week cycles of decitabine during past 2 years; or, intolerance to azacitidine or decitabine defined by drug-related ≥Grade 3 liver or renal toxicity leading to discontinuation during the past 2 years.
* Did not respond to, relapsed after, not eligible for, or opted not to do bone marrow transplantation
* Off other MDS treatments for at least 4 weeks; Filgrastim (G-CSF) and erythropoietin allowed before and during the study as clinically indicated.
* No need for induction chemotherapy
* ECOG status 0, 1 or 2
* Willing to adhere to protocol prohibitions and restrictions
* Patient (or a legally authorized representative) must sign informed consent form to indicate patient's understanding study's purpose and procedures and willingness to participate

Exclusion Criteria:

* Anemia due to factors other than MDS (including hemolysis or gastrointestinal bleeding) unless stabilized for 1 week after RBC transfusion.
* Any active malignancy within the past year, except basal cell or squamous cell skin cancer or carcinoma in situ of the cervix or breast
* 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.
* Alanine transaminase (ALT)/aspartate transaminase (AST) ≥2.5 x upper limit of normal (ULN)
* Serum creatinine ≥2.0 mg/dL
* Ascites requiring active medical management including paracentesis, or hyponatremia (defined as serum sodium value of \<130 mEq/L)
* Pregnant or lactating females
* Patients unwilling to follow strict contraception requirements (including condom use for males with sexual partners, and for females: prescription oral contraceptives \[birth control pills\], contraceptive injections, intrauterine device, double-barrier method \[spermicidal jelly or foam with condoms or diaphragm\], contraceptive patch, or surgical sterilization) before entry and throughout the study
* Females with reproductive potential who do not have a negative urine beta-human chorionic gonadotropin pregnancy test at screening
* Major surgery without full recovery or major surgery within 3 weeks of ON 01910.Na treatment start
* Uncontrolled hypertension (defined as systolic pressure ≥160 mmHg and/or diastolic pressure ≥110 mmHg)
* New onset seizures (within 3 months prior to first dose of ON 01910.Na) or poorly controlled seizures
* Any other concurrent investigational agent or chemotherapy, radiotherapy, or immunotherapy
* Prior treatment with low-dose cytarabine during past 2 years Investigational therapy within 4 weeks of starting ON 01910.Na
* Psychiatric illness or social situation that limits the patient's ability to tolerate and/or comply with study requirements