Open Label Extension Study of Romiplostim (AMG 531) in Thrombocytopenic Patients With Immune (Idiopathic) Thrombocytopenic Purpura (ITP)

An Open Label Study Evaluating the Safety and Efficacy of Long-Term Dosing of AMG 531 in Thrombocytopenic Subjects With Immune (Idiopathic) Thrombocytopenic Purpura (ITP)

The purpose of this study is to determine the safety of romiplostim as a long-term treatment in thrombocytopenic subjects with ITP, to evaluate the long-term platelet response to romiplostim, and to evaluate changes in patient reported outcomes due to the use of romiplostim. Participants must have previously completed a romiplostim ITP study.

Inclusion Criteria:

• Must have previously completed a romiplostim ITP study
• Platelet count ≤ 50 x 10 ^9/L
• Written informed consent

Exclusion Criteria:

• Bone marrow stem cell disorder or new active malignancies diagnosed since enrollment in the previous romiplostim ITP study
• Received any alkylating agents within 4 weeks before screening visit or anticipated use during the time of the proposed study
• Currently enrolled in or has not yet completed at least 4 weeks since ending device or drug trial(s) (other than the previous romiplostim ITP study), or subject is receiving other investigational agent(s) other than romiplostim
• Not using adequate contraceptive precautions
• Not available for follow-up assessments
• Has any kind of disorder that compromises the ability of the participant to give informed consent and does not have a legally-acceptable representative and/or is unable to comply with study procedures.