An Open-label Safety Study of S-888711

Inclusion Criteria:

• A signed and dated written informed consent
• Males and females ≥ 18 years of age
• All subjects must agree to use barrier contraception
• Diagnosis of ITP
• Subjects > 60 years must have had a diagnostic bone marrow aspiration
• Relapsed persistent or chronic ITP status
• Subjects receiving steroid therapy must be on a stable dose
• PT and APTT within 20% of the upper limit of normal
• Subjects receiving stable dosages of cyclosporine A, mycophenolate mofetil, azathioprine, or danazol are allowed

Exclusion Criteria:

• History of clinically important hemorrhagic clotting disorder
• Females who are pregnant, lactating, or taking oral contraceptives
• History of alcohol/drug abuse or dependence within 1 year

• Use of the following drugs or treatment prior to Visit 1 (Day 1):

  • Within 1 week - Rho(D) immune globulin or intravenous immunoglobulin;
  • Within 2 weeks - plasmaphoresis treatment;
  • Within 4 weeks - use of anti-platelet or anti-coagulant drugs;
  • Within 8 weeks - rituximab;
  • Within 12 weeks - alemtuzumab, multi-drug systemic chemotherapy, stem cell therapy;
• History of clinically significant cardiovascular or thromboembolic disease within 26 weeks prior to Initial Screening
• Splenectomy within 4 weeks prior to Initial Screening

• Clinically significant laboratory abnormalities

  • Hemoglobin < 10.0 g/dL for men or women, not clearly related to ITP
  • Absolute neutrophil count < 1000/mm3
  • Abnormal peripheral blood smear with evidence of fibrosis confirmed by bonemarrow biopsy
  • Total bilirubin > 1.5 x upper limit of normal
  • Alanine aminotransferase (ALT) > 1.5 x upper limit of normal
  • Aspartate aminotransferase (AST) > 1.5 x upper limit of normal
  • Creatinine > 1.5 x upper limit of normal
  • Human immunodeficiency virus positive
  • Hepatitis A IgM antibody positive, hepatitis B surface antigen or hepatitis C antibody positive
• Exposure to previous TPO mimetics/agonists (e.g., eltrombopag,romiplostim, E5501 [AKR-501] or LGD-4665) within 4 weeks prior to Initial Screening
• Subjects unresponsive to previous TPO mimetics/agonists (e.g., eltrombopag, romiplostim, E5501 [AKR-501] or LGD-4665)
• Exposure to an investigative medication within 4 weeks prior to the initial Screening Visit