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Study on Mavorixafor for Patients with Chronic Neutropenia Experiencing Recurrent or Serious Infections

Fast replyInvestigationalNo 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 a group of conditions known as neutropenias. Neutropenias are disorders where the body has a lower than normal number of a type of white blood cell called neutrophils, which are important for fighting infections. The study is particularly interested in people with chronic forms of these conditions, which can be either congenital (present from birth) or acquired later in life. These conditions can lead to frequent and serious infections.

The treatment being tested in this study is a medication called mavorixafor, which is taken as a capsule by mouth. The purpose of the study is to evaluate how effective mavorixafor is in reducing the rate of infections and improving the levels of neutrophils in the blood. Participants in the study will be randomly assigned to receive either mavorixafor or a placebo, which looks like the medication but does not contain the active ingredient. The study will last for about a year, during which participants will have regular check-ups to monitor their health and the effects of the treatment.

Throughout the study, participants will be closely monitored for any changes in their condition, including the frequency and severity of infections. The study aims to provide valuable information on the safety and tolerability of mavorixafor for people with chronic neutropenia. This research could potentially lead to new treatment options for managing these challenging conditions.

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, including age, weight, and medical history related to chronic neutropenia.

    A bone marrow biopsy or aspirate is required to ensure no evidence of blood-related cancer.

  2. Step 2

    Screening and baseline assessment

    During the screening phase, a blood test is conducted to measure the absolute neutrophil count (ANC).

    The baseline visit occurs at least two weeks before the first dose of the study medication, ensuring the ANC is below 1500 cells/µL without signs of infection.

  3. Step 3

    Medication administration

    Participants receive either mavorixafor or a placebo in the form of hard capsules taken orally.

    The dosage and frequency are determined by the study protocol, and participants must adhere to the prescribed schedule.

  4. Step 4

    Treatment period

    The treatment period lasts for 12 months, during which the effectiveness of mavorixafor is evaluated based on infection rates and ANC levels.

    Participants continue any existing therapies for chronic neutropenia, maintaining stable doses unless safety concerns arise.

  5. Step 5

    Monitoring and assessments

    Regular visits are scheduled to monitor health status, including blood tests to assess ANC and check for infections.

    Additional assessments may include questionnaires to evaluate fatigue and the presence of oral ulcers.

  6. Step 6

    End of study

    At the end of the 12-month period, a final assessment is conducted to evaluate the overall health and response to the treatment.

    Participants may be required to continue using contraception for a specified period after the last dose.

Who can join the trial?

11 criteria

  • Participants must be at least 12 years old when they sign the consent form.
  • A test called a bone marrow biopsy or aspirate must show no signs of blood cancer.
  • Participants must weigh at least 15 kilograms.
  • Men and women must use birth control methods that follow local rules. Abstinence is not considered a reliable method.
  • Participants must be able to give consent, or have a parent or guardian who can do so.
  • Participants must have a type of low white blood cell count called **chronic neutropenia** for at least 6 months. This condition should not be caused by medications, infections, or cancer.
  • Participants must have a confirmed low level of a type of white blood cell called **ANC** (absolute neutrophil count) below 1500 cells per microliter, with no signs of infection.
  • Participants must have had at least two serious infections in the past year that required antibiotics or a visit to a healthcare facility.
  • If participants are on a treatment called **G-CSF** or other therapies, they must have been on a stable dose for at least 4 weeks before the study and keep it stable during the study.
  • Participants must avoid certain drugs that affect how the body processes medications, starting 14 days before the study.
  • Participants must avoid grapefruit and Seville orange products, as they can affect medication processing.

Who cannot join the trial?

4 criteria

  • Patients who are currently receiving **chronic G-CSF treatment** cannot participate. G-CSF is a medication that helps the body make more white blood cells.
  • Patients with **chronic neutropenia** who are not receiving chronic G-CSF treatment are eligible, but those who are receiving it are excluded.
  • Patients who do not meet the age requirements for the study cannot participate. The study has specific age ranges that are eligible.
  • Patients who are part of a vulnerable population may not be eligible. A vulnerable population includes groups that might need special protection, like children or the elderly.
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Investigated drugs

Mavorixafor is a medication being studied for its ability to help people with certain types of chronic neutropenia, a condition where the body has a lower than normal number of neutrophils, a type of white blood cell important for fighting infections. This trial is looking at how well mavorixafor can reduce the rate of infections and improve the levels of neutrophils in the blood of participants who have chronic neutropenia and are not receiving ongoing treatment with G-CSF, a common therapy for this condition.

What is already known about the treatment

Mavorixafor – Mavorixafor is administered orally in the form of tablets. It is currently being studied in a Phase 3 clinical trial for its effectiveness in treating chronic neutropenia, a condition characterized by low levels of neutrophils, which are a type of white blood cell. The main therapeutic indication for mavorixafor is to reduce the rate of infections in individuals with congenital and acquired primary autoimmune and idiopathic chronic neutropenic disorders. At the molecular level, mavorixafor works by inhibiting the CXCR4 receptor, which plays a role in the movement and function of neutrophils. It is classified pharmacologically as a CXCR4 antagonist.

Investigated diseases

Neutropenias – Neutropenias are conditions characterized by an abnormally low count of neutrophils, a type of white blood cell essential for fighting off infections. This reduction in neutrophils can make individuals more susceptible to infections, as their immune system is compromised. Neutropenias can be chronic or acute, with chronic forms persisting over a longer period. The condition can arise from various causes, including bone marrow disorders, certain medications, or autoimmune diseases. Symptoms may include frequent infections, fever, and mouth ulcers. The severity of neutropenia can vary, influencing the risk and frequency of infections.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-508482-32-00Protocol codeX4P-001-110Estimated enrolment214 patientsSponsorX4 Pharmaceuticals Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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