Oral LGD-4665 Versus Placebo in Adults With Immune Thrombocytopenic Purpura (ITP) for 6 Weeks Plus Open Treatment Continuation

Inclusion Criteria:

• Adults 18 years or older
• Diagnosis of ITP for at least 3 months consistent with ASH guidelines
• Treated with one or more prior therapies for ITP and platelet counts < 30,000/µL or < 50,000/µL if on a stable oral corticosteroid for ≥ 4 weeks, supported by 2 platelet counts in prior 30 days

• Laboratory results within normal range except for the following analytes

  • Hemoglobin ≥ 10 g/dL
  • Absolute neutrophil counts > 1000/mL
  • ALT ≤ 1.5X ULN
  • AST ≤ 1.5X ULN
  • Creatinine < 1.5X ULN
  • Bilirubin < 1.5X ULN
  • BUN < 1.5X ULN
  • PT < 1.5X ULN
  • aPTT <1.5X ULN
• Women of child-bearing potential must have a negative serum pregnancy test within 4 days prior to the first dose of study treatment and agree to practice an approved method of contraception or abstinence from sexual intercourse.
• Willing to sign a written informed consent

Exclusion criteria:

• History of heart attack or cardiovascular disease
• Known history of arterial or venous thrombosis
• More than 3 risk factors for thromboembolic events (diabetes, smoker, using oral contraception, using estrogen therapy, hypertriglyceridemia, average cholesterol > 240 mg/dL, treatment for hypertension)
• Active cancer or a history of bone marrow disorders
• Women who are pregnant or nursing
• History of alcohol/drug abuse or dependence within one year

• Listed medications dosed within:

  • 4 weeks of the first dose of the study treatment:

    • Use of Rituximab
    • Use of cytotoxic agents
    • Use of Cyclosporine and other immunomodulators
    • Use of an investigational drug

  • 2 weeks of the first dose of the study treatment:

    • Use of Danazol
    • Use of Azathioprine
    • Use of Mycophenolate mofetil and pulsed-dose steroids

  • 1 week of the first dose of the study treatment:

    • Use of Anti-D (WinRho®)
    • Use of IVIG
    • Had a platelet transfusion
    • Use of herbal/dietary supplements (excluding vitamins and mineral supplements)

  • 3 days of the first dose of the study treatment

    • Use of aspirin, aspirin containing compounds
    • salicylates
    • milk of magnesia
    • non-steroidal anti-inflammatory drugs (unless prescribed for heart disease)
• History of platelet aggregation that would prevent measurement of platelet counts
• Known active infection with HIV, hepatitis B, or hepatitis C
• In the Investigator's opinion, the patient is not able to comply with requirements of the study