Open-Label Extension of Voxelotor

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: Terminated
• Conditions: Sickle Cell Disease
• Intervention / Treatment: Drug: Voxelotor

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: Interventional
• Enrollment (Actual): 162
• Phase: Phase 3

Expanded Access

No longer available outside the clinical trial. See expanded access record.

Contacts and Locations

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

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

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

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment Emergent Adverse Events (AEs)	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	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	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

• Sponsor: Pfizer
• Collaborators: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): November 18, 2019
• Primary Completion (Actual): November 1, 2024
• Study Completion (Actual): November 1, 2024

Study Registration Dates

• First Submitted: December 3, 2019
• First Submitted That Met QC Criteria: December 3, 2019
• First Posted (Actual): December 6, 2019

Study Record Updates

• Last Update Posted (Estimated): November 13, 2025
• Last Update Submitted That Met QC Criteria: October 30, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Hematologic Diseases; Anemia, Hemolytic, Congenital; Anemia, Hemolytic; Anemia; Hemoglobinopathies; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Hemic and Lymphatic Diseases; Anemia, Sickle Cell; voxelotor
• Other Study ID 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