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Study on the Effects of GLPG3667 for Adults with Dermatomyositis

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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 the effects of a new treatment for dermatomyositis, a rare inflammatory disease that affects the skin and muscles, causing muscle weakness and skin rashes. The treatment being tested is called GLPG3667, which is taken as a capsule once a day. The study will compare the effects of GLPG3667 with a placebo to see how well it works in reducing the symptoms of dermatomyositis.

The purpose of the study is to evaluate the effectiveness and safety of GLPG3667 over a period of 24 weeks. Participants will be randomly assigned to receive either the GLPG3667 capsule or a placebo. Throughout the study, participants will have regular check-ups to monitor their health and any changes in their symptoms. The study aims to determine if GLPG3667 can provide at least minimal improvement in the condition by the end of the 24 weeks.

In addition to assessing the improvement in symptoms, the study will also look at the safety and tolerability of GLPG3667. This includes monitoring any side effects that may occur during the treatment period. Participants who complete the initial 24-week period may have the opportunity to continue receiving GLPG3667 in an open-label extension, where all participants receive the active treatment. This extension will help further evaluate the long-term safety and benefits of the treatment.

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, you will be randomly assigned to receive either the study medication, GLPG3667, or a placebo. A placebo is a substance with no active medication, used to compare the effects of the actual drug.

  2. Step 2

    Medication administration

    You will take the assigned medication orally in the form of a capsule once daily. The duration of this phase is 24 weeks.

  3. Step 3

    Regular check-ups

    Throughout the 24-week period, you will have regular check-ups to monitor your health and the effects of the medication. These check-ups will include assessments of your muscle strength, skin condition, and overall health.

  4. Step 4

    End of initial treatment phase

    At the end of the 24 weeks, your progress will be evaluated to determine the effectiveness of the treatment. This will involve measuring any improvements in your condition according to specific criteria.

  5. Step 5

    Open label extension

    If you complete the initial 24-week treatment period, you may be eligible to continue in an open label extension phase. In this phase, all participants will receive GLPG3667 for further evaluation of its safety and tolerability.

  6. Step 6

    Final assessments

    Throughout the open label extension, and at its conclusion, you will undergo final assessments to monitor any long-term effects and gather additional data on the medication's impact.

Who can join the trial?

15 criteria

  • Participants must be female or male and between 18 to 75 years old on the date they sign the consent form.
  • Participants must have a diagnosis of dermatomyositis (DM) according to specific medical criteria for at least 3 months.
  • If diagnosed with dermatomyositis in the 3 years before the study, participants must have had a cancer screening within the last year.
  • Participants must show active disease through one of the following:
    • A specific type of rash with a score of 6 or more on a medical scale.
    • A creatinine kinase level more than 4 times the normal limit.
    • Evidence of active disease from a muscle biopsy within the last 3 months.
    • Signs of inflammation in muscles from a muscle MRI within the last 3 months.
    • Changes in muscles from an electromyography test within the last 3 months.
    • Any other clinical evidence of active disease confirmed by experts.
    • Participants must have reduced muscle strength and at least two other abnormal test results, such as:
      • A doctor’s or patient’s disease activity score greater than 2 on a 10 cm scale.
      • Extra-muscular disease activity score greater than 2 on a 10 cm scale.
      • A disability score greater than 0.25 on a specific questionnaire.
      • Elevated levels of muscle enzymes with at least one enzyme more than 1.5 times the normal limit.
      • Participants must have previously shown failure or intolerance to first-line treatments, or have active disease despite treatment. They should currently be on a stable dose of up to three treatments for dermatomyositis for at least 3 months.
      • For the open-label extension part of the study, participants must have completed the initial 24-week treatment period and may benefit from further treatment according to the investigator's judgment.

Who cannot join the trial?

9 criteria

  • Patients who have any other serious health conditions that could interfere with the study.
  • Patients who are currently participating in another clinical trial.
  • Patients who have had a recent infection that required treatment with antibiotics.
  • Patients who have a history of allergic reactions to similar medications.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of drug or alcohol abuse.
  • Patients who have received certain treatments for dermatomyositis within a specific time frame before the study.
  • Patients who have been vaccinated with a live vaccine within a certain period before the study.
  • Patients who have any condition that, in the opinion of the study doctor, makes them unsuitable for the study.
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Investigated drugs

GLPG3667 is a medication being tested in this clinical trial for its effectiveness in treating dermatomyositis, a condition that causes muscle weakness and skin rashes. The trial aims to see how well this medication works in reducing the symptoms of the disease. Participants in the study will take this medication orally once a day for 24 weeks. The trial also includes an open-label extension phase, where all participants will receive the medication to further assess its safety and how well people can tolerate it over time. This means that after the initial study period, everyone will know they are receiving the actual medication, not a placebo, to gather more information about its long-term effects.

What is already known about the treatment

GLPG3667 – GLPG3667 is an oral medication taken once daily, currently being studied for its effectiveness in treating dermatomyositis, a condition that causes muscle weakness and skin rashes. This medication is in the clinical trial phase, where researchers are evaluating its safety, tolerability, and how well it works compared to a placebo. GLPG3667 is designed to target specific pathways in the body that are involved in inflammation, aiming to reduce the symptoms associated with dermatomyositis. It falls under the category of drugs that modulate the immune system to help manage autoimmune conditions.

Investigated diseases

Dermatomyositis – Dermatomyositis is an inflammatory disease characterized by muscle weakness and a distinctive skin rash. It primarily affects the skin and muscles, leading to symptoms such as a violet or dusky red rash, often on the face, eyelids, knuckles, elbows, knees, chest, and back. Muscle weakness typically occurs in the hips, thighs, shoulders, upper arms, and neck, making it difficult to climb stairs, lift objects, or perform other daily tasks. The disease progresses with increasing muscle weakness and skin changes, which can vary in severity. Over time, dermatomyositis may also affect other organs, including the lungs and heart. The exact cause of dermatomyositis is unknown, but it is believed to involve an autoimmune response.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2022-501097-19-00Protocol codeGLPG3667-CL-214Estimated enrolment40 patientsSponsorGalapagos

sourced from the EU Clinical Trials Register and site verification

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