Open-Label Extension of Voxelotor

October 30, 2025 updated by: Pfizer

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

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

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
162

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Expanded Access

Expanded Access

A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration (FDA). Also called compassionate use. There are different expanded access types.
No longer available

No longer available

  • Available: Expanded access is currently available for this investigational treatment, and patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.
  • No longer available: Expanded access was available for this intervention previously but is not currently available and will not be available in the future.
  • Temporarily not available: Expanded access is not currently available for this intervention but is expected to be available in the future.
  • Approved for marketing: The intervention has been approved by the U.S. Food and Drug Administration for use by the public.
 outside the clinical trial. See expanded access record.

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Egypt
      • Alexandria, Egypt, 21131
        • Alexandria University Hospital - Clinical Research Center
      • Cairo, Egypt, 11562
        • Cairo University Hospital, Abu El Rish Hospital
      • Cairo, Egypt
        • Ain Shams University Hospital - Clinical Research Center (MASRI-CRC)
    • Alsharkia
      • Zagazig, Alsharkia, Egypt
        • Zagazig University Hospital
  • Lebanon
      • Beirut, Lebanon
        • American University of Beirut - Medical Center
      • Tripoli, Lebanon
        • Nini Hospital
  • Nigeria
      • Kaduna, Nigeria, 800212
        • Barau Dikko Teaching Hospital/Kaduna State University
      • Kano, Nigeria, 700233
        • Aminu Kano Teaching Hospital
      • Lagos, Nigeria, 100254
        • Lagos University Teaching Hospital
    • Cross River State
      • Calabar, Cross River State, Nigeria, 540281
        • University of Calabar Teaching Hospital
    • Oyo State
      • Ibadan, Oyo State, Nigeria, 200212
        • College of Medicine, University of Ibadan
  • United Kingdom
      • London, United Kingdom, SE1 7EH
        • Guy's and St Thomas' NHS Foundation Trust
      • London, United Kingdom, E1 1BB
        • Barts Health NHS Trust , The Royal London Hospital
    • Greater London
      • London, Greater London, United Kingdom, NW1 2PG
        • University College Hospital NHS Foundation Trust
  • United States
    • District of Columbia
      • Washington D.C., District of Columbia, United States, 20010
        • Children's National Medical Center
    • Georgia
      • Atlanta, Georgia, United States, 30342
        • Children's Healthcare of Atlanta Scottish Rite
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Ann & Robert H. Lurie Children's Hospital of Chicago
    • Missouri
      • Kansas City, Missouri, United States, 64108
        • Children's Mercy Hospital
    • North Carolina
      • Greenville, North Carolina, United States, 27834
        • ECU Physicians, Brody Outpatient Clinic
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15224
        • UPMC Children's Hospital of Pittsburgh

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

6 months and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Voxelotor
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
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).
Other Names:
  • GBT440

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Participants With Treatment Emergent Adverse Events (AEs)
Time Frame: From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)
An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered to be drug related. A treatment emergent AE was defined as an AE with an onset date on or after the date of informed consent until 28 days after discontinuation of drug. AEs included both serious AEs (SAEs) and all non-SAEs. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of the either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.
From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)
Number of Participants With SAEs
Time Frame: From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)
An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered to be drug related. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of the either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.
From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)
Number of Participants With Sickle Cell Disease (SCD) Related TEAEs and SAEs
Time Frame: From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)
SCD-related AEs were common complications associated with the study participant's SCD and were not considered to be related to voxelotor unless judged by the investigator to have worsened in severity and/or frequency or changed in nature during the study. SCD-related complications included the following: sickle cell anemia with crisis, acute chest syndrome (ACS), pneumonia, priapism, and osteonecrosis. A treatment emergent AE was defined as an AE with an onset date on or after the date of informed consent until 28 days after discontinuation of drug. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.
From date of informed consent until 28 days after last dose of study drug (maximum up to 4.31 years)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pfizer

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Pfizer

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 18, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 3, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 3, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 6, 2019

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 13, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 30, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • GBT440-038
  • C5341023 (Other Identifier: Alias Study Number)
  • 2019-003144-76 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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