Study of a New Medication for Childhood Chronic Immune Thrombocytopenia (ITP), a Blood Disorder of Low Platelet Counts That Can Lead to Bruising Easily, Bleeding Gums, and/or Bleeding Inside the Body.

Inclusion Criteria

• •Written informed consent must be obtained from the patient's guardian and accompanying informed assent from the patient (for children over 6 years old)
• •Patients must be between 1 year and \<18 years of age at Day 1
• •Patients will have a confirmed diagnosis of chronic ITP for at least 1 year, at screening, according to the guidelines published in the International Working Group Report
• •A peripheral blood smear or bone marrow examination will support the diagnosis of ITP with no evidence of other causes of thrombocytopenia.
• •Patients must be refractory or have relapsed after at least one prior ITP therapy, or patients must be unable, for a medical reason, to continue other ITP treatments.
• •Patients must have a Day 1 (or within 48 hours prior) platelet count \<30 Gi/L.
• •Previous therapy for ITP with immunoglobulins (IVIg and anti-D) must have been completed at least 2 weeks prior to Day 1, or these therapies must have been completed at least 1 week prior to Day 1 and have been clearly ineffective.
• •Previous treatment for ITP with splenectomy, rituximab and cyclophosphamide must have been completed at least 4 weeks prior to Day 1.
• •Patients treated with concomitant ITP medication (e.g. corticosteroids or azathioprine) must be receiving a dose that has been stable for at least 4 weeks prior to Day 1.
• •Patients must have a complete blood count (CBC) not suggestive of another hematological disorder.
• •Patients must have the following laboratory results:
• •prothrombin time international normalized ratio (INR) and activated partial thromboplastin time (aPTT) within 80 to 120% of the normal range.
• •clinical chemistries that do NOT exceed the upper limit of normal reference range by more than 20% for the following: creatinine, ALT, AST, total bilirubin, and alkaline phosphatase.
• •total albumin that is not below the lower limit of normal by more than 10%.
• •Female patients of child-bearing potential (after menarche) must:
• •have a negative pregnancy test within 24 hours of first dose of study treatment,
• •agree and be able to provide a blood or urine specimen for pregnancy testing during the study,
• •agree to use effective contraception during the study and for 28 days following the last dose of study treatment, and not be lactating.
• •Male patients with a female partner of childbearing potential must agree to use effective contraception from 2 weeks prior to administration of the first dose of study treatment until 3 months after the last dose of study treatment.
• •In France, a patient will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category.