Sickle Cell DiseasePhase 2/3NCT05632354

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

A Phase 2/3 study testing Osivelotor in people with Sickle Cell Disease, run by Pfizer at 9 sites in 2 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record

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Trial summary

An Open-label Extension Study of GBT021601 in Participants with Sickle Cell Disease Read more about this study

Who is it for?: Ages 6 months and older
Conditions the study is for: Sickle Cell Disease
What is being tested?: Osivelotor
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 47 participants
Where: 9 sitesin 2 countries
Study dates: 5 Jan 2023to 13 Feb 2025
Phase: Phase 2/3
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 6 months and older
All sexes
No healthy volunteers
Child, Adult, Older adult

Who may be able to join

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.
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.
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

Show all 9Show fewer

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
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.

Who cannot join

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

Trial locations and contacts

9 sites in 2 countries.

Country

City, postcode or hospital

9 sites in 2 countries

United States6 sites

Our Lady of the Lake Hospital, Inc.
Baton Rouge, Louisiana, 70808
Inova Schar Cancer Institute
Fairfax, Virginia, 22031
University of Texas Health Science Center
Houston, Texas, 77030
Mississippi Center for Advanced Medicine
Madison, Mississippi, 39110
University Medical Center Inpatient Pharmacy
New Orleans, Louisiana, 70112
University Medical Center New Orleans
New Orleans, Louisiana, 70112

Other trials in United States

Nigeria3 sites

University College Hospital Ibadan
Ibadan, Oyo/ibadan North, 200212
Aminu kano Teaching Hospital
Kano, 700233
Lagos University Teaching Hospital
Lagos, 100254

Other trials in Nigeria

About this study

Official title: 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

Read the 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

Conditions: Sickle Cell Disease
Being tested: Osivelotor
Medical subject headings: Anemia, Sickle Cell

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

OsivelotorDrug
Osivelotor

Study groups in NCT05632354
Study group	Role	What they receive
Treatment	Experimental	Osivelotor Receives: Drug: Osivelotor

What is being measured

The primary outcome is the main question the study is designed to answer.

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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline, Week 12
Change From Baseline in Leukocytes Week 48
Change from baseline in leukocytes at week 48 were reported in this outcome measure.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline, Week 48

Secondary outcomes (6)

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.
Measured: 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).
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline, Weeks 12, 24, 36, 48, and 60

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

5 Jan 202313 Feb 2025

First posted30 Nov 2022
Study start5 Jan 2023
Primary completion13 Feb 2025
Study completion13 Feb 2025

Why it stopped: Study terminated as data obtained from this non-placebo-controlled trial may not be informative for the interpretation of the benefits and risks of osivelotor

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Sickle Cell DiseaseStudies of the same condition, open and under way.
More trials run by PfizerThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2/3
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 47 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05632354
Sponsor's protocol ID: GBT021601-022
Other IDs: C5351005
Status last verified: Mar 2026
First submitted: 1 Nov 2022
Last updated: 19 Mar 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: 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.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

Active, not recruitingPhase 1/2
Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Long-term Mitapivat Dosing in Subjects With Stable Sickle Cell Disease: An Extension of a Phase I Pilot Study of Mitapivat
Sickle Cell Disease, Hemolytic Anemia
RecruitingObservational study
HPC Offered for PRESERVE Expansion
Bone Marrow Transplant (BMT)
RecruitingPhase 1
Study to Evaluate the Safety and Tolerability of Escalating Doses of Fostamatinib in Subjects With Stable Sickle Cell Disease
Sickle Cell Disorders, Sickle Cell Disease
RecruitingPhase 4
Clinical and Biomarker Effects of Depot Medroxyprogesterone Acetate in Females With Sickle Cell Disease
Sickle Cell Disease (SCD), Vaso-Occlusive Pain Episode in Sickle Cell Disease
Not yet recruitingPhase 1
Buprenorphine for the Management of Pain in Children With Sickle Cell Disease
Sickle Cell Disease (SCD), Sickle Cell Disease Vaso-occlusive Crisis

All Sickle Cell Disease trials

Study at a glance

From the registry record, last updated by the sponsor on 19 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: 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
ClinicalTrials.gov ID: NCT05632354
Acronym / sponsor ID: GBT021601-022
Conditions: Sickle Cell Disease
Phase: Phase 2/3
Study type: Interventional
Recruitment status: TerminatedReason stopped: Study terminated as data obtained from this non-placebo-controlled trial may not be informative for the interpretation of the benefits and risks of osivelotor
Enrolment: 47 participants (actual)
Lead sponsor: PfizerIndustry (pharma, biotech, devices)
Study start: 5 Jan 2023 (actual)
Primary completion: 13 Feb 2025 (actual)
Study completion: 13 Feb 2025 (actual)
First posted: 30 Nov 2022 (actual)
Results: Posted 19 Mar 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

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

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 design

Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
Treatment	Experimental	Drug: OsivelotorOsivelotor

Who may qualify

Ages: 6 months and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Child, Adult, Older adult

Key inclusion criteria (9 listed)

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.
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.
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:

Key exclusion criteria (5 listed)

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

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
OsivelotorOsivelotor	Drug	Treatment

Primary outcome

Number of Participants With Treatment Emergent Adverse Events (TEAEs)
Time frame: From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days)
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.
Change From Baseline in Hematocrit at Week 12
Time frame: Baseline, Week 12
Change from baseline in hematocrit at week 12 were reported in this outcome measure.
Change From Baseline in Hematocrit at Week 48
Time frame: Baseline, Week 48
Change from baseline in hematocrit at week 48 were reported in this outcome measure.
Change From Baseline in Leukocytes at Week 12
Time frame: Baseline, Week 12
Change from baseline in leukocytes at week 12 were reported in this outcome measure.
Change From Baseline in Leukocytes Week 48
Time frame: Baseline, Week 48
Change from baseline in leukocytes at week 48 were reported in this outcome measure.
Change From Baseline in Supine Blood Pressure (SBP) at Week 12
Time frame: Baseline, Week 12
Change from baseline in SBP at week 12 were reported in this outcome measure.
Change From Baseline in SBP at Week 48
Time frame: Baseline, Week 48
Change from baseline in SBP at week 48 were reported in this outcome measure.
Change From Baseline in Diastolic Blood Pressure (DBP) at Week 12
Time frame: Baseline, Week 12
Change from baseline in DBP at week 12 were reported in this outcome measure.
Change From Baseline in DBP at Week 48
Time frame: Baseline, Week 48
Change from baseline in DBP at week 48 were reported in this outcome measure.

6 secondary outcomes

Annualized Rate of Vaso-Occlusive Crisis (VOC)
Time frame: 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)
Time frame: 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
Time frame: Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Reticulocytes at Weeks 12, 24, 36, 48, and 60
Time frame: Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Lactate Dehydrogenase (LDH) at Weeks 12, 24, 36, 48, and 60
Time frame: Baseline, Weeks 12, 24, 36, 48, and 60
Change From Baseline in Unconjugated Bilirubin at Weeks 12, 24, 36, 48, and 60
Time frame: Baseline, Weeks 12, 24, 36, 48, and 60

Results and safety

Results posted to the registry on 19 Mar 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Participants Without Delayed Start: Osivelotor 100 Milligram (mg)	18	0
Participants Without Delayed Start: Osivelotor 150 mg	17	0
Participants Without Delayed Start: Osivelotor 200 mg	1	0
Participants With Delayed Start: Osivelotor 100 mg	5	0
Participants With Delayed Start: Osivelotor 150 mg	6	0

Primary outcome: Number of Participants With Treatment Emergent Adverse Events (TEAEs)

Time frame: From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days). Count of participants. Unit: Participants

Measure	Participants Without Delayed Start: Osivelotor 100 mg n = 18	Participants Without Delayed Start: Osivelotor 150 mg n = 17	Participants Without Delayed Start: Osivelotor 200 mg n = 1	Participants With Delayed Start: Osivelotor 100 mg n = 5	Participants With Delayed Start: Osivelotor 150 mg n = 6
TEAE	14	13	1	5	6
Treatment related TEAE	4	0	0	0	0
Treatment emergent SAEs	5	4	1	2	2
Treatment-Related Treatment-Emergent SAEs	1	0	0	0	0
Treatment Emergent Non-Serious AEs	14	13	1	5	5

Primary outcome: Change From Baseline in Hematocrit at Week 12

Time frame: Baseline, Week 12. Mean (Standard Deviation). Unit: Percent

Measure	Participants Without Delayed Start: Osivelotor 100 mg n = 15	Participants Without Delayed Start: Osivelotor 150 mg n = 12	Participants Without Delayed Start: Osivelotor 200 mg n = 1	Participants With Delayed Start: Osivelotor 100 mg n = 5	Participants With Delayed Start: Osivelotor 150 mg n = 6
Value	-0.3 (5.88)	-3.9 (7.53)	-1.9 (NA)	7.0 (5.74)	10.0 (2.37)

Population analysed: Safety analysis set included all enrolled participants who had received at least one dose of study drug in this OLE study. Participants were analyzed according to the assigned daily maintenance dose on study day 1 in the OLE study. Here, 'Overall Number of Participants Analyzed' (N) signifies participants evaluable for this outcome measure.

Primary outcome: Change From Baseline in Hematocrit at Week 48

Time frame: Baseline, Week 48. Mean (Standard Deviation). Unit: Percent

Measure	Participants Without Delayed Start: Osivelotor 100 mg n = 12	Participants Without Delayed Start: Osivelotor 150 mg n = 12	Participants Without Delayed Start: Osivelotor 200 mg n = 1	Participants With Delayed Start: Osivelotor 100 mg n = 4	Participants With Delayed Start: Osivelotor 150 mg n = 5
Value	-2.4 (7.71)	-5.5 (8.61)	-9.9 (NA)	4.5 (4.12)	5.5 (5.00)

Population analysed: Safety analysis set included all enrolled participants who had received at least one dose of study drug in this OLE study. Participants were analyzed according to the assigned daily maintenance dose on study day 1 in the OLE study. Here, 'Overall Number of Participants Analyzed' signifies participants evaluable for this outcome measure.

Primary outcome: Change From Baseline in Leukocytes at Week 12

Time frame: Baseline, Week 12. Mean (Standard Deviation). Unit: 10^9 cells per liter (10^9 cells/L)

Measure	Participants Without Delayed Start: Osivelotor 100 mg n = 15	Participants Without Delayed Start: Osivelotor 150 mg n = 12	Participants Without Delayed Start: Osivelotor 200 mg n = 1	Participants With Delayed Start: Osivelotor 100 mg n = 5	Participants With Delayed Start: Osivelotor 150 mg n = 6
Value	1.7 (2.68)	0.8 (1.87)	0.9 (NA)	0.3 (1.92)	-1.8 (2.28)

Population analysed: Safety analysis set included all enrolled participants who had received at least one dose of study drug in this OLE study. Participants were analyzed according to the assigned daily maintenance dose on study day 1 in the OLE study. Here, 'Overall Number of Participants Analyzed' signifies participants evaluable for this outcome measure.

6 secondary outcomes are reported in the full results.

Adverse events

Time frame: From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days). Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Participants Without Delayed Start: Osivelotor 100 mg	5 of 18 (27.8%)	14 of 18 (77.8%)	0 of 18
Participants Without Delayed Start: Osivelotor 150 mg	4 of 17 (23.5%)	13 of 17 (76.5%)	0 of 17
Participants Without Delayed Start: Osivelotor 200 mg	1 of 1 (100%)	1 of 1 (100%)	0 of 1
Participants With Delayed Start: Osivelotor 100 mg	2 of 5 (40%)	5 of 5 (100%)	1 of 5
Participants With Delayed Start: Osivelotor 150 mg	2 of 6 (33.3%)	5 of 6 (83.3%)	0 of 6

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 19 Mar 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
To obtain contact information for a study center near you, click here.Link provided by the sponsor.
Individual participant dataSharing planned: Yes. 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.

Related trials for Sickle Cell Disease

Active, not recruitingPhase 1/2
Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Long-term Mitapivat Dosing in Subjects With Stable Sickle Cell Disease: An Extension of a Phase I Pilot Study of Mitapivat
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Pfizer CT.gov Call Center study director

Pfizer

9 sites in 2 countries: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing Osivelotor in people with Sickle Cell Disease, run by Pfizer at 9 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 9 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 19 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 9 sites in United States, Nigeria. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 19 Mar 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of Participants With Treatment Emergent Adverse Events (TEAEs) (time frame: From first dose of study drug up to 56 days after last dose of study drug (approximately up to 736 days)). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05632354.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Mar 2026.