Safety and Efficacy Study of PF-06835375 in Primary Immune Thrombocytopenia

Inclusion Criteria: * Diagnosis of Primary ITP. Ongoing ITP (platelet counts \<50 x 109/L) \[No severe bleeding within 1 month or during screening\] AND Persistent ITP (3 to 12 months) or Chronic ITP \>12 months Exclusion Criteria: * Bleeding event according to the WHO grading scale ≥2 occurring ≤4 weeks prior to screen OR a current bleeding event that, in the opinion of the investigator, requires treatment with standard of care therapy OR require blood or blood products during screening * Splenectomy within 3 months of randomization or planned during the study duration.