GBT021601-022: A Study of GBT021601 in Participants With Sickle Cell Disease (SCD)

An Open-label Extension Study to Evaluate the Long-term Safety of GBT021601 Administered to Participants With Sickle Cell Disease Who Have Participated in a GBT021601 Clinical Trial

An Open-label Extension Study of GBT021601 in Participants with Sickle Cell Disease

Study Overview

• Status: Terminated
• Conditions: Sickle Cell Disease
• Intervention / Treatment: Drug: Osivelotor

Detailed Description

An Open-label Extension Study to Evaluate the Long-term Safety and Efficacy of GBT021601 Administered to Participants with Sickle Cell Disease Who Have Participated in a GBT021601 Clinical Trial

• Study Type: Interventional
• Enrollment (Actual): 47
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• Nigeria
  • Kano, Nigeria, 700233
    • Aminu Kano Teaching Hospital
  • Lagos, Nigeria, 100254
    • Lagos University Teaching Hospital
  • Oyo/ibadan North
    • Ibadan, Oyo/ibadan North, Nigeria, 200212
      • University College Hospital Ibadan
• United States
  • Louisiana
    • Baton Rouge, Louisiana, United States, 70808
      • Our Lady of the Lake Hospital, Inc.
    • New Orleans, Louisiana, United States, 70112
      • University Medical Center New Orleans
    • New Orleans, Louisiana, United States, 70112
      • University Medical Center Inpatient Pharmacy
  • Mississippi
    • Madison, Mississippi, United States, 39110
      • Mississippi Center for Advanced Medicine
  • Texas
    • Houston, Texas, United States, 77030
      • University of Texas Health Science Center
  • Virginia
    • Fairfax, Virginia, United States, 22031
      • INOVA Schar Cancer Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 2 years to 61 years (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male or female aged 6 months or older with SCD who participated and received study drug or placebo in a previous osivelotor clinical study and completed the end of treatment visit.

   Note: Participants who discontinued study drug in the originating study due to an TEAE, but who remained on study, may be eligible for treatment in this study provided the TEAE does not pose a risk for treatment with osivelotor.

2. Females of childbearing potential are required to have a negative urine pregnancy test prior to dosing on Day 1.

   Note: Females who become of childbearing potential during the study must be willing to have negative urine pregnancy tests to remain in the study.

3. If sexually active, females of childbearing potential must consistently use highly effective methods of contraception consistently throughout the study and for at least 120 days after the last dose of study drug. If sexually active, male participants must use barrier methods of contraception until 84 days after the last dose of study drug. Male participants are eligible to participate if they agree to the following requirements during the study intervention period and for 84 days after the last dose of study intervention:

   • Refrain from donating sperm PLUS either
   • Be abstinent from heterosexual intercourse as their preferred and usual lifestyle OR
   • Must agree to use a male condom when engaging in any activity that allows for passage of ejaculate to another person
4. Participant has provided written informed consent/assent. For underage participants, both the consent of the participant's legal representative or legal guardian and the participant's assent (where applicable) must be obtained based on local requirements.

Exclusion Criteria:

• Participant withdrew consent or was noncompliant from the originating osivelotor clinical study
• Current or recent use of voxelotor. Recent use is defined as within 10 days prior to Day 1
• Current or recent use of crizanlizumab. Recent use is defined as within 90 days prior to Day 1
• Participant has any medical, psychological, safety, or behavioral conditions that, in the opinion of the Investigator, may confound safety interpretation, interfere with compliance, or preclude informed consent
• Has received an investigational drug (including investigational vaccines) within 5 times the elimination half-life (if known) or within 30 days (if the elimination half-life- is unknown) prior to study drug administration or is concurrently enrolled in any research judged not to be scientifically or medically compatible with this study

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: Treatment; Osivelotor	Drug: Osivelotor; Osivelotor

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment Emergent Adverse Events (TEAEs)	An adverse event (AE) was any untoward medical occurrence in a participant administered a pharmaceutical product during the course of a clinical investigation. Serious adverse events (SAEs) were defined as any untoward medical occurrence that, at any dose, met one or more of the criteria: death, life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, congenital anomaly or birth defect and other medically significant events. TEAEs are events between first dose of study drug and up to 56 days after last dose that were absent before treatment or that worsened relative to pretreatment state. Relatedness of any AE to treatment was based on investigator decision. AEs included both SAEs and all non-serious AEs.	From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days)
Change From Baseline in Hematocrit at Week 12	Change from baseline in hematocrit at week 12 were reported in this outcome measure.	Baseline, Week 12
Change From Baseline in Hematocrit at Week 48	Change from baseline in hematocrit at week 48 were reported in this outcome measure.	Baseline, Week 48
Change From Baseline in Leukocytes at Week 12	Change from baseline in leukocytes at week 12 were reported in this outcome measure.	Baseline, Week 12
Change From Baseline in Leukocytes Week 48	Change from baseline in leukocytes at week 48 were reported in this outcome measure.	Baseline, Week 48
Change From Baseline in Supine Blood Pressure (SBP) at Week 12	Change from baseline in SBP at week 12 were reported in this outcome measure.	Baseline, Week 12
Change From Baseline in SBP at Week 48	Change from baseline in SBP at week 48 were reported in this outcome measure.	Baseline, Week 48
Change From Baseline in Diastolic Blood Pressure (DBP) at Week 12	Change from baseline in DBP at week 12 were reported in this outcome measure.	Baseline, Week 12
Change From Baseline in DBP at Week 48	Change from baseline in DBP at week 48 were reported in this outcome measure.	Baseline, Week 48

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Annualized Rate of Vaso-Occlusive Crisis (VOC)	A VOC was defined as an acute episode of pain that had no medically determined cause other than a vaso-occlusive event, and resulted in a visit to a medical facility (hospitalization, emergency department, urgent care center, outpatient clinic, or infusion center), and required parenteral narcotic agents, parenteral nonsteroidal anti-inflammatory drugs (NSAIDs), or an increase in treatment with oral narcotics. Annualized rate of VOC was reported in this outcome measure.	From the first dose of study drug up to last dose of study drug (approximately up to 680 days)
Number of Participants With Sickle Cell Disease (SCD) Related Serious Adverse Events (SAEs)	SCD is an inherited disorder caused by a point mutation in the beta globin gene which leads to formation of sickle hemoglobin (HbS). SAEs were defined as any untoward medical occurrence that, at any dose, meets one or more of the criteria: death, life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, congenital anomaly or birth defect and other medically significant events. Participants with delayed start are those with a gap in dosing greater than 42 consecutive days from completing the originating study (C5351005 Date of First Dose - C5351004 End of Treatment Date + 1 greater than 42).	From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days)
Change From Baseline in Hemoglobin at Weeks 12, 24, 36, 48, and 60	Change from baseline in hemoglobin at weeks 12, 24, 36, 48 and 60 were reported in this outcome measure.	Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Reticulocytes at Weeks 12, 24, 36, 48, and 60	Change from baseline in reticulocytes at weeks 12, 24, 36, 48 and 60 were reported in this outcome measure.	Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Lactate Dehydrogenase (LDH) at Weeks 12, 24, 36, 48, and 60	Change from baseline in LDH at weeks 12, 24, 36, 48 and 60 were reported in this outcome measure.	Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Unconjugated Bilirubin at Weeks 12, 24, 36, 48, and 60	Change from baseline in unconjugated bilirubin at weeks 12, 24, 36, 48 and 60 were reported in this outcome measure.	Baseline, Weeks 12, 24, 36, 48, and 60

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): January 5, 2023
• Primary Completion (Actual): February 13, 2025
• Study Completion (Actual): February 13, 2025

Study Registration Dates

• First Submitted: November 1, 2022
• First Submitted That Met QC Criteria: November 21, 2022
• First Posted (Actual): November 30, 2022

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: March 1, 2026

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
• Other Study ID Numbers: GBT021601-022; C5351005 (Other Identifier: Alias Study 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