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Study of momelotinib in patients with VEXAS syndrome and myelodysplastic syndrome who are dependent on or do not respond to steroid treatment

Verified siteInvestigationalNo 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 investigates the use of momelotinib (GSK3070785) in patients with VEXAS syndrome, a rare condition that causes inflammation throughout the body, with or without associated myelodysplastic syndrome, a group of blood disorders where the bone marrow doesn't produce enough healthy blood cells. The purpose of this study is to determine the most appropriate dose of momelotinib and evaluate how well it works in managing symptoms in patients who have not responded well to steroid treatment.

The study medication will be given as tablets taken by mouth. The treatment period will last up to 48 weeks, during which patients will receive momelotinib at doses up to 300 mg per day. The study consists of two parts: first, a safety phase to find the right dose, followed by a second phase to test how well the medication works.

During the study, doctors will monitor patients' symptoms and response to treatment, particularly focusing on improvements in VEXAS syndrome symptoms and any changes in blood cell production. They will also track how well patients can reduce their use of steroids while taking the study medication. Throughout the treatment period, patients will have regular check-ups to monitor their health and any side effects.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment period

    You will receive momelotinib tablets for oral use. The exact dose will be determined during the first phase of the study.

    During the first 4 weeks (first cycle), your health will be closely monitored to determine how well you tolerate the medication.

    An additional 4-week period may be needed to observe any side effects.

  2. Step 2

    Ongoing treatment and monitoring

    Your response to the treatment will be evaluated at weeks 4, 12, and 24 after starting the medication.

    Regular blood tests will be conducted to monitor your condition.

    Your steroid medication dose may be adjusted during this period.

    The effects of the treatment on your symptoms will be assessed.

  3. Step 3

    Extended follow-up

    Your progress will continue to be monitored up to 48 weeks after starting treatment.

    Blood samples will be taken to measure the effectiveness of the treatment.

    Your overall health status will be evaluated at regular intervals.

    Any side effects will be recorded and monitored using standardized criteria.

  4. Step 4

    Final assessment

    A comprehensive evaluation will be conducted at 12 months to assess your overall response to the treatment.

    The final assessment will include blood tests and evaluation of your symptoms.

    The effectiveness of the treatment in reducing your need for steroids will be evaluated.

    Any changes in your condition will be documented.

Who can join the trial?

16 criteria

  • Must be at least 18 years old
  • Must have VEXAS syndrome confirmed by a UBA1 mutation test and have symptoms requiring treatment with immunosuppressive medications and at least 10 mg per day of glucocorticoids (steroid medications)
  • Must have symptoms that are not well controlled with previous treatments, including steroids
  • Must have a performance status of 0-2 (ability to perform daily activities ranging from fully active to being up and about more than 50% of waking hours)
  • Must have adequate liver function as shown by blood tests
  • Must have adequate kidney function (kidney filtration rate above 30 ml/min)
  • Must provide written informed consent
  • Can be taking only steroid medication at the time of joining the study
  • Must stop other immune system medications 28 days before starting the study medication
  • Cannot have received erythropoietin or luspatercept (medications that stimulate red blood cell production) within 28 days before joining
  • For women who can become pregnant:
    • Must have a negative pregnancy test within 24 hours before starting treatment
    • Must use effective birth control from 4 weeks before treatment until 12 weeks after treatment ends
    • Must agree to learn about egg preservation procedures
    • Cannot be breastfeeding
    • For men:
      • Must use condoms during sexual activity with women who can become pregnant, during treatment and for 12 weeks after
      • Must agree to learn about sperm preservation procedures

Who cannot join the trial?

15 criteria

  • Age below 18 years
  • Active, uncontrolled systemic infections (infections affecting the whole body)
  • History of malignancy (cancer) within the past 5 years, except for successfully treated skin cancer
  • Severe heart conditions including:
    • Uncontrolled high blood pressure
    • Recent heart attack
    • Unstable heart disease
    • Severe liver disease or abnormal liver function tests
    • Severe kidney disease or significantly reduced kidney function
    • Pregnant or breastfeeding women
    • Currently participating in other clinical trials
    • Unable to provide informed consent
    • Known allergic reactions to similar medications
    • Significant mental health conditions that could interfere with study participation
    • Use of prohibited medications that could interact with the study drug
    • Any condition that, in the investigator's opinion, makes the patient unsuitable for the study
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Investigated drugs

Momelotinib is a medication being studied for treating VEXAS syndrome, which is a rare inflammatory condition. This medication works by blocking certain proteins that are involved in inflammation and blood cell production. It's taken orally (by mouth) and is being tested to help reduce symptoms in patients who haven't responded well to steroid treatments. The medication is particularly being studied in patients who may also have a condition called myelodysplastic syndrome, which affects blood cell production in the bone marrow.

What is already known about the treatment

Momelotinib – An oral JAK inhibitor medication that is administered in tablet form for treating inflammatory conditions and myeloid disorders. It works by blocking specific enzymes called Janus kinases (JAK1/JAK2), which are involved in inflammation and blood cell production pathways at the molecular level. The drug is currently being investigated in clinical trials for treating VEXAS syndrome (a rare autoinflammatory condition) and myelodysplastic syndrome, particularly in patients who are dependent on or refractory to steroid treatments. As a kinase inhibitor class medication, momelotinib shows promise in managing both inflammatory symptoms and blood disorders through its dual mechanism of action.

Investigated diseases

  • Myelodysplastic syndrome

    A blood disorder where bone marrow fails to produce enough healthy blood cells. The condition occurs when blood-forming cells in the bone marrow become abnormal, leading to low numbers of one or more types of blood cells. This causes patients to have too few healthy blood cells, with symptoms developing gradually over time. The condition primarily affects older adults and can make people feel tired and short of breath.

  • VEXAS syndrome

    A rare genetic condition caused by mutations in the UBA1 gene on the X chromosome. The disease causes inflammation throughout the body, affecting multiple systems and tissues. Patients develop unusual vacuoles (small cavities) in certain blood cells. The condition typically causes recurrent fevers, skin problems, and affects blood cell production. The symptoms tend to be ongoing and can vary in severity over time.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519779-24-00Protocol codeGFM-VEXAS-MMBEstimated enrolment57 patientsSponsorGroupe Francophone Des Myelodysplasies

sourced from the EU Clinical Trials Register and site verification

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