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Study on Voxelotor for Reducing Hemolysis in Patients with Sickle Cell Disease

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying sickle cell disease, a condition that affects the red blood cells, causing them to become misshapen and break down. The treatment being tested in this study is a medication called Voxelotor, which is taken as a 500 mg film-coated tablet. The purpose of the study is to evaluate how well Voxelotor works in reducing the breakdown of red blood cells in people with sickle cell disease.

Participants in the study will take Voxelotor orally over a period of up to 52 weeks. Throughout the study, various health assessments will be conducted to monitor the effects of the medication. These assessments will include measuring the levels of hemoglobin in the blood, which is a protein in red blood cells that carries oxygen. The study will also look at other health indicators such as blood flow to the brain, kidney function, and overall physical performance.

The study aims to see if Voxelotor can improve the health of people with sickle cell disease by reducing the damage to their red blood cells and improving blood flow and organ function. Participants will be closely monitored for any changes in their condition and any side effects from the medication. The results of this study could provide valuable information about the potential benefits of Voxelotor for individuals living with sickle cell disease.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria such as age, hemoglobin levels, and medical history related to sickle cell disease.

    A negative pregnancy test is required for female participants, along with effective birth control methods during the study.

  2. Step 2

    Medication administration

    The medication used in this study is Oxbryta, which contains the active substance voxelotor.

    Participants will take Oxbryta 500 mg film-coated tablets orally. The dosage and frequency will be determined by the study protocol.

  3. Step 3

    Monitoring and assessments

    Throughout the study, various assessments will be conducted to monitor the effects of voxelotor on sickle cell disease.

    Primary assessments include measuring the reduction of hemolysis, which is the breakdown of red blood cells, by evaluating plasma hemoglobin levels over a period of 48 weeks.

  4. Step 4

    Secondary assessments

    Secondary assessments involve a range of tests such as measuring blood volumes, cerebral perfusion, and cognitive performance.

    Additional tests include evaluating renal function, blood viscosity, and the properties of red blood cells.

  5. Step 5

    Safety evaluations

    Safety is monitored by observing any adverse events or changes in health status, including conditions like vaso-occlusive crises or acute chest syndrome.

    Regular check-ups and tests are conducted to ensure participant safety throughout the study.

  6. Step 6

    Completion of the study

    The study is expected to conclude by September 2025, with final assessments and data collection occurring at the end of the study period.

    Participants will receive a summary of their health status and any relevant findings from the study.

Who can join the trial?

7 criteria

  • Must have a type of **sickle cell disease** known as SS or S-β0 major sickle cell syndrome.
  • Must have a **hemoglobin level** less than 9 grams per deciliter (g/dL). Hemoglobin is a protein in red blood cells that carries oxygen.
  • Must be 18 years old or older.
  • If receiving certain treatments like HU (hydroxyurea), EPO (erythropoietin), ACE inhibitors, ARBs, glutamine, or crizanlizumab, the dose must be stable for at least 3 months. For HU treatment, it must be at least 6 months since starting.
  • Must have social security.
  • If female, must have a negative pregnancy test or be post-menopausal, which means having stopped having periods for a year or more.
  • Must use effective birth control methods, such as condoms, spermicidal gel, birth control pills, intrauterine devices, hormonal implants or patches, injections, approved cervical rings, or abstain from sexual activity from the start of the study until 4 weeks after the last dose of the study medication.
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Investigated drugs

Voxelotor is a medication being studied for its potential to improve conditions related to sickle cell disease. It works by reducing the breakdown of red blood cells, which is known as hemolysis. This reduction in hemolysis is measured by the levels of hemoglobin in the blood. The goal of using Voxelotor in this trial is to see if it can help decrease the damage to organs caused by sickle cell disease by stabilizing the red blood cells.

What is already known about the treatment

Voxelotor – Voxelotor is administered orally in tablet form. It is currently being studied in clinical trials for its potential benefits in treating sickle cell disease. The main therapeutic indication for Voxelotor is to reduce hemolysis, which is the breakdown of red blood cells, in patients with sickle cell disease. At the molecular level, Voxelotor works by binding to hemoglobin, increasing its affinity for oxygen, and thereby stabilizing the red blood cells. It is classified pharmacologically as a hemoglobin modulator.

Investigated diseases

Sickle Cell Disease – Sickle cell disease is a genetic disorder that affects the shape and function of red blood cells. Normally, red blood cells are round and flexible, allowing them to move easily through blood vessels. In sickle cell disease, these cells become rigid and shaped like a crescent or sickle. This abnormal shape can cause the cells to get stuck in small blood vessels, leading to blockages that slow or stop the flow of blood and oxygen to parts of the body. Over time, this can result in pain, organ damage, and other complications. The disease is chronic and can vary in severity among individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-513096-41-00Protocol codeAPHP200750Estimated enrolment35 patientsSponsorAssistance Publique Hopitaux De Paris

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