Romiplostim (AMG 531) Versus Medical Standard of Care for Immune (Idiopathic) Thrombocytopenic Purpura

This is a phase 3b, multi-center, randomized, Standard of Care (SOC)-controlled, open-label, 52-week treatment study to compare romiplostim to medical SOC for Idiopathic Thrombocytopenia Purpura (ITP), with a 6-month Safety Follow-up. Patients randomized to romiplostim must complete the taper or discontinuation of medical SOC for ITP as soon as medically feasible after the initiation of romiplostim. After the completion or discontinuation of the study treatment period, any participant who does not transfer in to another romiplostim study will complete a 6-month Safety Follow-up period.