Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects With Immune Thrombocytopenia for ≥6 Months

Study Overview
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Brief Summary
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A Phase 3b Study to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects with Immune Thrombocytopenia for ≥6 Months

Detailed Description
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Subjects will be randomized in to blinded therapy of avatrombopag or placebo in a 3:1 ratio for a period of 12 weeks. Subjects who complete the 12 week treatment period and are eligible may continue to the open label extension phase which will last 2 years.

Official Title
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Randomized, Double-blind, Placebo-controlled Study With Open-label Extension Phase to Evaluate the Efficacy and Safety of Avatrombopag for the Treatment of Thrombocytopenia in Pediatric Subjects With Immune Thrombocytopenia for ≥6 Months

Conditions
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Immune Thrombocytopenia

Intervention / Treatment
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* Drug: Avatrombopag
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female participants ≥1 and <18 years of age at Screening and Baseline with a diagnosis of primary ITP for ≥6 months duration and has had an insufficient response to a previous treatment, in the opinion of the Investigator. Participant has an average of 2 platelet counts <30×10^9/L with no single count >35×10^9/L in the screening period Exclusion Criteria: Participants must not have a known history of secondary ITP, any history of arterial or venous thrombosis, including partial or complete thrombosis, known inherited thrombocytopenia, a history of myelodysplastic syndrome (MDS) or known history of congenital heart abnormalities or arrhythmias.

Ages Eligible for Study
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Minimum Age: 1 Year
Maximum Age: 17 Years

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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Experimental: Avatrombopag<br>Study is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks | Drug: Avatrombopag<br>* Oral avatrombopag Tablet<br>* Other names: Doptelet;|
| Placebo Comparator: Placebo Comparator:Placebo<br>Study is 3:1 randomization ratio (avatrombopag to placebo). Investigational product administered orally once daily for 12 weeks | Drug: Placebo<br>* Placebo comparator tablet<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Durable platelet response | The proportion of subjects achieving at least 6 out of 8 weekly platelet counts ≥50×10^9/L during the last 8 weeks of the 12 week Treatment Period in the Core Phase, in the absence of rescue medication | Last 8 weeks of 12 week treatment regimen | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Platelet Counts | The percentage of weeks subjects have a platelet count ≥50×10^9/L during 12 weeks of treatment in the Core Phase, in the absence of rescue therapy. | 12 weeks of treatment | 
| Platelet response | The proportion of subjects with a platelet count ≥50×10^9/L at day 8, in the absence of rescue therapy. | Day 8 | 
| Platelet percentage | The percentage of weeks subjects have a platelet count between ≥50×10^9/L and ≤150×10^9/L, during 12 weeks of treatment in the Core Phase, in the absence of rescue therapy. | 12 weeks | 
| Rescue medications | The proportion of subjects who require rescue medications during 12 weeks of treatment in the Core Phase of the study. | 12 weeks | 
| Bleeding Symptoms | Incidence and severity of bleeding symptoms associated with Immune thrombocytopenia (ITP) measured using the World Health Organization (WHO) Bleeding Scale. | Throughout study | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ITP