Inclusion Criteria
MDS classified as follows:
RAEB-1 per World Health Organization (WHO) MDS criteria (5% to merican-British (FAB) classification (20% to 30% BM blasts)
At least one cytopenia (ANC cording to 2006 IWG criteria) at any time after initiation of AZA or DAC treatment or Failure to achieve complete or partial response or hematological improvement (HI) (according to 2006 IWG) after at least six 4-week cycles of AZA or either four 4-week or four 6-week cycles of DAC administered or Relapse after initial complete or partial response or HI (according to 2006 IWG criteria)
Duration of prior HMA therapy ? 9 months
Last dose of AZA or DAC within 6 months before the planned date of randomization; however, must be off these treatments for ? 4 weeks before randomization
Has failed to respond to, relapsed following, not eligible for, or opted not to participate in allogeneic stem cell transplantation
Off all treatments for MDS (including AZA and DAC) for ? 4 weeks before randomization; growth factors (G-CSF, erythropoietin and thrombopoietin) and transfusions are allowed before and during the study as clinically indicated
Eastern Cooperative Oncology Group (ECOG) performance status of 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
Patients with 5q- syndrome should have failed to respond to or progressed on treatment with lenalidomide
Exclusion Criteria
Previous participation in a clinical study of IV or oral rigosertib; patients who failed screening for other rigosertib studies may be screened for participation
Eligible to receive induction chemotherapy, such as 7-10 days of cytosine arabinoside plus 2-3 days of an anthracycline, or high-dose cytarabine
Suitable candidate to receive allogeneic stem cell transplantation; patient is eligible for study if a suitable candidate refuses to undergo an allogeneic stem cell transplant or a suitable donor cannot be found
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 or unstable angina pectoris
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 - Known HIV, hepatitis B or hepatitis C
Uncorrected hyponatremia (defined as serum sodium value of 30%).