Inclusion Criteria:

          -  Diagnosis of MDS by World Health Organization criteria, and either

               1. International Prognostic Scoring System (IPSS) low risk or intermediate-1 risk
                  without 5q deletion and failed treatment (no response, loss of response,
                  progressive disease/treatment intolerance) following:

                  i. 4 cycles hypomethylating agent; or ii. 4 cycles hypomethylating agent, or
                  lenalidomide or erythropoietin stimulating agent (ESA).

               2. IPSS low risk or intermediate-1 risk with 5q deletion and failed treatment
                  following:

                  i. 4 cycles of lenalidomide and hypomethylating agent; or ii. 4 cycles of
                  lenalidomide.

               3. IPSS intermediate-2 risk or high risk and failed treatment following 4 cycles
                  hypomethylating agent.

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 2

          -  Screening laboratory values:

               1. Renal glomerular filtration rate (GFR) ≥ 60 ml/min;

               2. Aspartate aminotransferase (AST) / Alanine aminotransferase (ALT) ≤ 3.0 times
                  upper limit of normal;

               3. Bilirubin < 1.5 times upper limit of normal;

               4. No history of HIV being HIV positive;

               5. No active Hepatitis B or Hepatitis C infection.

          -  Life expectancy ≥ 12 weeks.

          -  Women of childbearing potential (WOCBP) must use study specified contraception.

          -  WOCBP demonstrate negative pregnancy test.

          -  Not breastfeeding.

          -  Men sexually active must use study specified contraception.

        Exclusion Criteria:

          -  Use of chemotherapeutic agents or experimental agents for MDS within 14 days of the
             first day of study drug treatment.

          -  Use of erythroid stimulating agents, Granulocyte-colony stimulating factor (G-CSF), or
             Granulocyte-macrophage colony-stimulating factor (GM-CSF) within 14 days of the first
             day of study drug treatment, or during the study.

          -  Mean triplicate heart rate-corrected QT interval (QTc) > 500 msec.

          -  Any of the following cardiac abnormalities:

               1. QT interval > 480 msec corrected using Fridericia's formula;

               2. Risk factors for Torsade de Pointes;

               3. Use of medication that prolongs the QT interval;

               4. Myocardial infarction ≤ 6 months prior to first day of study drug treatment;

               5. Unstable angina pectoris or serious uncontrolled cardiac arrhythmia.

          -  Any serious or uncontrolled medical disorder.

          -  Prior malignancy within the previous 3 years except for local cancers that have been
             cured.

          -  Within 14 days of the first study drug treatment requiring systemic treatment with
             either corticosteroids or immunosuppressive medications. Corticosteroid adrenal
             replacement doses are permitted.

          -  Use of other investigational drugs within 30 days of study drug administration.

          -  Major surgery within 4 weeks of study drug administration.

          -  Live-virus vaccination within 30 days of study drug administration.

          -  Allergy to study drug component.