Efficacy and Safety of Oral E5501 Plus Standard of Care for the Treatment of Thrombocytopenia in Adults With Chronic Immune Thrombocytopenia (Amendment 02)

"Permitted ITP concomitant background therapies are as follows:~* Corticosteroids and/or azathioprine taken at a stable dose for 4 weeks before randomization;~* Mycophenolate mofetil (MMF) or danazol taken at a stable dose for at least 12 weeks before randomization;~* Cyclosporine A (CsA) (due to the fact that it is a P-glycoprotein-mediated transport \[P-gp\] inhibitor) is to be avoided unless deemed medically necessary; CsA taken at a stable dose for at least 12 weeks before randomization.~At the discretion of the investigator, participants will be allowed to use aspirin, other salicylates, or approved adenosine diphosphate (ADP) receptor antagonists, (eg, clopidogrel, prasugrel) during the study once their platelet count had risen.~Participants treated with proton pump inhibitors (PPIs) and H2 antagonist therapy will receive a stable dose for at least 6 weeks prior to randomization. Treatment with these therapies must have been completed at least 2 weeks prior to randomization."