Open-Label Extension of Voxelotor

Study Overview
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Brief Summary
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Open-label extension study of voxelotor for participants with Sickle Cell Disease who have participated in voxelotor clinical trials.

Detailed Description
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Open-label extension (OLE) study of voxelotor for participants with Sickle Cell Disease who have participated in voxelotor clinical trials. Up to approximately 600 participants with sickle cell disease (SCD), will be enrolled at approximately 70 clinical sites globally. All participants will receive voxelotor once daily, administered orally as tablets, dispersible tablets, or powder for oral suspension formulation. The objective of this OLE is to assess the safety of, and SCD-related complications of, long-term treatment with voxelotor, in participants who have completed treatment in a Global Blood Therapeutics (GBT)-sponsored voxelotor clinical study.

Official Title
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An Open-Label Extension Study of Voxelotor Administered Orally to Participants With Sickle Cell Disease Who Have Participated in Voxelotor Clinical Trials

Conditions
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Sickle Cell Disease

Intervention / Treatment
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* Drug: Voxelotor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female participant with SCD, who participated and received study drug in a GBT-sponsored voxelotor clinical study. Note: Participants who discontinued study drug due to an AE, but who remained on study, may be eligible for treatment in this study provided the AE does not pose a risk for treatment with voxelotor. Note: Participants who discontinued Study GBT440-032 as the result of an abnormal transcranial Doppler (TCD) flow velocity assessment (≥ 200 cm/sec) are eligible for treatment in this study. - Participant has provided written consent/assent (for pediatric participants, both the consent of the participant's legal representative or legal guardian and the participant's assent [where applicable] must be obtained). Exclusion Criteria: Female participant who is breastfeeding or pregnant Participant withdrew consent from a GBT-sponsored voxelotor clinical study Known hypersensitivity to voxelotor or any other components of the study drug Use of St. John's wort, sensitive cytochrome P450 (CYP) 3A4 substrates with a narrow therapeutic index, or moderate or strong CYP3A4 inducers within 30 days of Day 1

Ages Eligible for Study
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Minimum Age: 6 Months
Maximum Age: 18 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
Intervention Model: Single Group Assignment
Interventional Model Description: Open-Label Extension study available to eligible participants from GBT-sponsored voxelotor clinical studies.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Voxelotor<br>All participants will receive voxelotor once daily (QD), administered orally as tablets, dispersible tablets, or a stick pack formulation (powder blend formulation packaged as stick packs). Participants aged ≥ 12 years and/or ≥ 40 kgs will receive a voxelotor dose of 1500 mg QD. Participants aged < 12 years and < 40 kgs will receive weight based dosing of voxelotor. The participant's weight at study entry will be used to determine the starting voxelotor dose in this study. Participants may receive study drug as long they continue to receive clinical benefit that outweighs risk as determined by the investigator and/or until the participant has access to voxelotor from an alternative source. | Drug: Voxelotor<br>* All participants will receive voxelotor once daily (QD), administered orally as tablets, dispersible tablets, or a powder for oral suspension formulation (powder formulation packaged as stick packs).<br>* Other names: GBT440;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| TEAEs and SAEs | Treatment Emergent Adverse Events and Serious Adverse Events | Throughout entire study | 
| Sickle Cell Disease-Related Complications | Frequency of SCD-related complications | Throughout entire study |