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

Study Overview
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Brief Summary
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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.

Official Title
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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)

Conditions
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Thrombocytopenia, Idiopathic Thrombocytopenic Purpura

Intervention / Treatment
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* Biological: Romiplostim


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 1 Year

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Romiplostim<br>Romiplostim weekly subcutaneous dosing based on screening weight and platelet count. Starting dose of 1 µg/kg up to a maximum dose of 10 µg/kg. | Biological: Romiplostim<br>* Romiplostim is supplied in a 5 mL single use glass vial as a sterile, white, preservative-free, lyophilized powder.<br>* Other names: Nplate;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Adverse Events | Participants with one or more occurrences of one or more adverse events up to 8 weeks after the end of treatment. Participants with more than one event were only counted once. | Duration of treatment plus 8 weeks (up to 285 weeks) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With a Platelet Response | Platelet response was defined as having a platelet count of ≥ 50 x 10^9/L at any time on study, excluding platelet counts within 8 weeks after receiving any rescue medications. | Duration of treatment (up to 277 weeks) | 
| Number of Participants With a Reduction or Discontinuation of Concurrent ITP Therapies | The number of participants with a reduction or discontinuation of concurrent immune (idiopathic) thrombocytopenic purpura (ITP) therapies (corticosteroids, danazol, azathioprine) during the study. | Duration of treatment (up to 277 weeks) | 
| Change From Baseline in ITP Patient Assessment Questionnaire | The ITP Patient Assessment Questionnaire (ITP-PAQ) assesses ITP-specific health-related quality of life (HRQOL). This questionnaire assesses ITP specific health-related quality of life (HRQOL). The questionnaire consists of 44 items and has six domains: These domains assess the impact of ITP on Physical Health, Mental Health, Work, Social Activity, Women's Health and Overall QOL. The impact of ITP on Physical Health consists of four sub-scales, which evaluate ITP related Symptoms, Fatigue, Bother and Activity. The impact of ITP on Mental Health consists of two sub-scales, which evaluate Psychological distress and Fear in a population with ITP. Items are scored from 0-100 with higher scores indicating better HRQOL. | Baseline to Week 48 | 
| Change From Baseline in Short Form 36 (SF-36) | The SF-36 is a widely used generic health-related quality of life measure. It has 36 questions with 8 domains: Physical Functioning, Role Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role Emotional and Mental Health. Items are scored from 0 to 100 with higher scores indicating better health status. | Baseline to Week 48 | 
| Change From Baseline in Euroqol-5D (EQ-5D) Index Score | The EQ-5D is a patient-completed, multidimensional measure of health related quality of life. The instrument is applicable to a wide range of health conditions and treatments and results in a single index score and a visual analog scale (VAS) score. The EQ-5D descriptive health profile comprises five dimensions of health (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression). Each dimension comprises three levels (no problems, some/moderate problems, extreme problems). A unique EQ-5D health state is defined by combining one level from each of the five dimensions. EQ-5D index values range from -0.59 to 1.00. Higher EQ-5D Index scores represent better health status. | Baseline to Week 48 | 
| Change From Baseline in Euroqol-5D (EQ-5D) Visual Analogue Scale (VAS) | The EQ-5D is a patient-completed, multidimensional measure of health related quality of life. The EQ-5D VAS records the respondent's self-rated health status on a vertical graduated (0-100) visual analogue scale. Higher EQ-5D VAS scores represent better health status. | Baseline to Week 48 | 
| Patient Global Assessment | The Patient Global Assessment is two questions which assess the overall health-related quality of life (HRQOL) and symptoms of the patient. Each item is answered on a 15-point Likert scale ranging from 'A very great deal worse' (1) to 'A very great deal better' (15). A higher score indicates that quality of life or symptoms have improved. | Week 1 and Week 48 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Immune (Idiopathic) Thrombocytopenic Purpura (ITP), Thrombocytopenic