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Sickle Cell Anemia in ChildrenPhase 2VoxSCANNCT05018728

The Effect of Voxelotor on Cerebral Hemodynamic Response in Children With Sickle Cell Anemia

A Phase 2 study testing Voxelotor in people with Sickle Cell Anemia in Children, run by Emory University at 2 sites in United States.

Terminated

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

Official record
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Trial summary

Voxelotor is a new drug for adolescents and adults with sickle cell disease that improves hemoglobin levels and reduces the incidence of worsening anemia. However, it is unclear whether this increase in hemoglobin is associated with a reduction in cerebral metabolic stress. Read more about this study

Who is it for?
Ages 4 to 30 years
Conditions the study is for
Sickle Cell Anemia in Children
What is being tested?
Voxelotor
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
22 participants
Where
2 sitesUnited States
Study dates
28 Mar 2022to 22 Oct 2024
Phase
Phase 2
Are there results?
None posted in the registry

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 4 to 30 years
  • All sexes
  • No healthy volunteers
  • Child, Adult

Who may be able to join

  • Written informed parental/guardian consent and participant assent/consent has been obtained per institutional review board (IRB)/Ethics Committee (EC) policy and requirements, consistent with International Conference on Harmonization (ICH) guidelines
  • Stated willingness to comply with all study procedures and availability for the duration of the study
  • Male or female participants, ages 4 to 30 years, inclusive
  • Homozygous hemoglobin SS (HbSS) or hemoglobin S/beta^0 thalassemia (HbS/β^0 thal)
  • Hemoglobin (Hb) ≤10.5 g/dL at baseline
  • Concomitant hydroxyurea (HU) therapy is allowed if the dose has been stable for at least 3 months with no anticipated need for dose adjustments during the study and no sign of hematological toxicity
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  • Ability to take oral medication and willingness to adhere to daily voxelotor and scheduled DCS/NIRS assessments
  • If sexually active and female, must agree to abstain from sexual intercourse or to use a highly effective method of contraception throughout the study period and for 30 days after discontinuation of study drug. If sexually active and male, must agree to abstain from sexual intercourse or willing to use barrier methods of contraception throughout the study period and for 30 days after discontinuation of study drug.
  • Females of child-bearing potential, i.e., who have begun menstruation and are sexually active, are required to have a negative pregnancy test at screening before the initial administration of study drug.

Who cannot join

  • Any one of the following requiring medical attention within 14 days prior to signing the informed consent form (ICF):
  • Vaso-occlusive crisis (VOC)
  • Acute chest syndrome (ACS)
  • Splenic sequestration crisis
  • Dactylitis
  • Requires chronic transfusion therapy
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  • Red blood cell (RBC) transfusion within 60 days of signing the ICF
  • Renal dysfunction requiring chronic dialysis or creatinine ≥1.5 mg/dL
  • Hepatic dysfunction characterized by alanine aminotransferase (ALT) >4× upper limit of normal (ULN) for age
  • Clinically relevant cardiac abnormality, in the opinion of the Investigator, such as:
  • Hemodynamically significant heart disease, e.g., congenital heart defect, uncompensated heart failure, or any unstable cardiac condition
  • An arrhythmic heart condition requiring medical therapy
  • Corrected QT interval by Fridericia (QTcF) >450 msec, congenital long QT syndrome, second- or third-degree heart block at rest (with the exception of asymptomatic Mobitz type I second degree heart block)
  • Received an investigational drug within 30 days or 5 half-lives, whichever is longer, of signing the ICF
  • Heavy smoker (defined as smoking more than 10 cigarettes/day or its nicotine equivalent including e-cigarettes)
  • Unlikely to comply with the study procedures
  • Other medical, psychological, or addictive condition that, in the opinion of the Investigator, would confound or interfere with evaluation of safety and/or pharmacokinetics (PK) of the investigational drug, prevent compliance with the study protocol, or preclude informed consent
  • Any condition affecting drug absorption, such as major surgery involving the stomach or small intestine (prior cholecystectomy is acceptable)
  • History of malignancy within the past 2 years prior to treatment Day 1 requiring chemotherapy and/or radiation (with the exception of local therapy for non-melanoma skin malignancy)
  • Clinically significant bacterial, fungal, parasitic, or viral infection currently receiving or that will require therapy
  • Participants with acute bacterial infection requiring antibiotic use should delay screening until the course of antibiotic therapy has been completed and the infection has resolved, in the opinion of the investigator
  • Known active hepatitis A, B, or C infection or human immunodeficiency virus (HIV)-positive; known active
  • Known active malaria
  • Pregnant patients
  • Evidence of abnormal high blood flow velocities on transcranial doppler (TCD) of 200 cm/sec or more

Trial locations and contacts

2 sites in 1 country.

United States2 sites

  • Children's Healthcare of Atlanta

    Atlanta, Georgia, 30322

  • Aflac Sickle Cell Comprehensive Clinics at Children's Healthcare of Atlanta, Scottish Rite

    Atlanta, Georgia, 30342

Other trials in United States

About this study

Voxelotor is a new drug for adolescents and adults with sickle cell disease that improves hemoglobin levels and reduces the incidence of worsening anemia. However, it is unclear whether this increase in hemoglobin is associated with a reduction in cerebral metabolic stress. This study will measure the effects of voxelotor on cerebral hemodynamics.

Read the detailed description

Sickle cell disease (SCD) is a genetic blood disorder that has profound effects on the brain. In the presence of chronic anemia, the brain microvasculature dilates in order to maintain adequate oxygen delivery to the tissue. As cerebral blood flow increases and the vasculature becomes maximally dilated, oxygen extraction fraction (OEF) increases to keep up with metabolic demand. Unfortunately, this state of maximized response leaves the brain vulnerable and ill-equipped to adapt to increased metabolic demand; consequently, the tissue is susceptible to infarction when blood flow/volume are insufficient to maintain sufficient oxygen metabolism.

Voxelotor is a first-in-class drug approved by the FDA for treatment of adults and children (aged four years and older) with SCD. This study will examine the effects of voxelotor on cerebral hemodynamics. The researchers hypothesize that as hemoglobin increases due to voxelotor, cerebral blood flow and oxygen extraction fraction will decrease. To test this hypothesis, measurements of brain blood flow, oxygen extraction, and oxygen metabolism will be made using a customized diffuse correlation spectroscopy and frequency domain near-infrared spectroscopy system (DCS/fdNIRS). This non-invasive, optical technique uses light to estimate an average oxygen saturation of the microvasculature, i.e., capillaries, arterioles, and venules.

All participants will receive voxelotor, administered orally once daily as tablets, dispersible tablets or as powder for oral suspension at a dose based on their body weight, for 12 weeks. Measurements of cerebral blood flow, oxygen extraction, and oxygen metabolism will be made at baseline (before starting drug), and at 4, and 12 weeks after the start of voxelotor.

Being tested
Voxelotor

What participants receive

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

  • VoxelotorDrug

    Also called Oxbryta

    Voxelotor is taken orally once a day. Participants 12 years or older will take 1500 mg/day. Participants younger than 12 years of age will receive a dose based on their body weight to provide exposure corresponding to the adult dose of 1500 mg/day.

Study groups in NCT05018728
Study groupRoleWhat they receive
VoxelotorExperimentalChildren with sickle cell anemia taking voxelotor for 12 weeks.
Receives: Drug: Voxelotor

What is being measured

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

  1. Change in cerebral blood flow (CBF)

    CBF will be measured by diffuse correlation spectroscopy and frequency domain near-infrared spectroscopy (DCS/FDNIRS).

    Measured: Baseline, Weeks 4 and 12

  2. Change in oxygen extraction fraction (OEF)

    OEF will be measured by DCS/FDNIRS. OEF is defined as the difference between arterial and venous oxygen content and it increases to keep up with metabolic demand.

    Measured: Baseline, Weeks 4 and 12

  3. Change in cerebral metabolic rate of oxygen (CMRO2)

    CMRO2 will be measured by DCS/FDNIRS. CMRO2 is the rate that the brain consumes oxygen and is a marker of brain health.

    Measured: Baseline, Weeks 4 and 12

Secondary outcomes (2)

  1. Change in total hemoglobin

    Total hemoglobin levels will be assessed and the correlation between changes in CBF, OEF and CMRO2 and change in hemoglobin at 4 and 12 weeks will be evaluated.

    Measured: Baseline, Weeks 4 and 12

  2. Change in RBC content of voxelotor-modified hemoglobin

    RBC levels in voxelotor-modified hemoglobin will be assessed and the correlation between changes in CBF, OEF and CMRO2 and change in voxelotor-modified hemoglobin at 4 and 12 weeks will be evaluated.

    Measured: Baseline, Weeks 4 and 12

Timeline

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

  1. First posted24 Aug 2021
  2. Study start28 Mar 2022
  3. Primary completion22 Oct 2024
  4. Study completion22 Oct 2024

Why it stopped: This study was terminated on September 26, 2024 due to voluntary withdrawal of study drug from the market.

Resources

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
Primary purpose
Supportive care
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
22 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05018728
Sponsor's protocol ID
STUDY00002483
Acronym
VoxSCAN
Status last verified
Oct 2025
First submitted
18 Aug 2021
Last updated
12 Dec 2025
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Individual participant data that underlie the results reported in the publication of this study (text, tables, figures, and appendices) will be made available for sharing, after de-identification

Publications

  • Brothers RO, Turrentine KB, Akbar M, Triplett S, Zhao H, Urner TM, Goldman-Yassen A, Jones RA, Knight-Scott J, Milla SS, Bai S, Tang A, Brown RC, Buckley EM. The influence of voxelotor on cerebral blood flow and oxygen extraction in pediatric sickle cell disease. Blood. 2024 May 23;143(21):2145-2151. doi: 10.1182/blood.2023022011.

    PubMed 38364110

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Voxelotor in people with Sickle Cell Anemia in Children, run by Emory University at 2 sites in United States.

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 25 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 12 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. 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 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.

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

Are results available for this study?

The study was stopped early (reason given: This study was terminated on September 26, 2024 due to voluntary withdrawal of study drug from the market.). Results are not available in the source record.

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?

Change in cerebral blood flow (CBF) (time frame: Baseline, Weeks 4 and 12). The study lists 3 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 NCT05018728, which also lists 1 linked publication.

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 12 Dec 2025; AzTrials last refreshed its copy on 8 Nov 2026.

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