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Study of emapalumab in children and adults with Macrophage Activation Syndrome (MAS) occurring in Still's Disease or Systemic Lupus Erythematosus

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 study focuses on treating Macrophage Activation Syndrome (MAS), a severe inflammatory condition that can occur in patients with Still's Disease (including both children and adults) and Systemic Lupus Erythematosus. The condition being studied causes the immune system to become overactive, leading to inflammation throughout the body. The study will test a medication called emapalumab, which is given through an intravenous infusion.

The purpose of this research is to determine if emapalumab can effectively treat MAS in patients who have not responded well enough to standard treatments with high-dose steroids. The medication works by targeting specific proteins in the body that are involved in inflammation. The study will include both children and adults between 6 months and 80 years of age.

During the study, participants will receive emapalumab through an intravenous infusion for up to 28 days. The maximum daily dose will be 6 milligrams per kilogram of body weight. Patients will be monitored for 8 weeks after starting the treatment to evaluate how well the medication works. The study will look at how the treatment affects inflammation levels in the body and whether it allows patients to reduce their steroid medication use.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial eligibility verification

    Your age should be between 6 months and 80 years

    You must have a confirmed diagnosis of active MAS (Macrophage Activation Syndrome) with fever and specific blood test results

    You must have already received high-dose intravenous steroids for at least 3 days without adequate improvement

  2. Step 2

    Treatment initiation

    You will receive emapalumab through an intravenous infusion

    The treatment will continue while monitoring your response

    Your current steroid dose may be gradually reduced based on your response to treatment

  3. Step 3

    Monitoring period

    Your response to treatment will be evaluated over 8 weeks after starting emapalumab

    Regular blood tests will be performed to check your condition

    Your doctor will monitor for any signs of MAS recurrence

  4. Step 4

    Safety requirements

    If you are a woman who can become pregnant, you must use effective birth control during treatment and for 6 months after the last dose

    Acceptable birth control methods include hormone-containing contraceptives, intrauterine devices, or other approved methods

    Regular safety assessments will be conducted throughout the treatment period

  5. Step 5

    Treatment completion

    The study will evaluate if your condition has improved completely or partially

    Your steroid dose will be reviewed to determine if it can be reduced to less than half of the starting dose

    Long-term monitoring will continue to check for any return of MAS symptoms

Who can join the trial?

12 criteria

  • Age requirement: Patients must be between 6 months and 80 years old at the time of active MAS diagnosis
  • Must provide informed consent (for adults) or have consent from legal representatives with patient assent when applicable
  • Must have active MAS (Macrophage Activation Syndrome) with:
    • Fever and high ferritin levels (above 684 ng/mL)
    • At least 2 of the following:
      • Low blood platelet count (≤181 x109/L)
      • Elevated liver enzymes (AST >48 U/L)
      • High blood fat levels (triglycerides >156 mg/dL)
      • Low fibrinogen levels (≤360 mg/dL)
      • Must have inadequate response to high-dose intravenous steroids given for at least 3 days
      • For Cohort 1 patients:
        • Must have confirmed systemic juvenile idiopathic arthritis (sJIA) or Adult onset Still's disease (AOSD)
        • For Cohort 2 patients:
          • Must have confirmed systemic lupus erythematosus (SLE)
          • For women who can become pregnant:
            • Must use effective birth control methods during treatment and for 6 months after the last dose
            • Acceptable methods include hormonal contraception, intrauterine devices, tubal ligation, or having a partner with vasectomy

Who cannot join the trial?

12 criteria

  • Active or chronic infections, including but not limited to tuberculosis (TB), HIV, or hepatitis B or C
  • Previous treatment with any cell therapy or gene therapy within 6 months before starting the study
  • History of cancer within the past 5 years (except successfully treated non-melanoma skin cancer)
  • Severe heart conditions, including heart failure or uncontrolled high blood pressure
  • Severe liver problems or abnormal liver function tests
  • Severe kidney problems or significantly reduced kidney function
  • Current pregnancy or breastfeeding
  • Known allergic reactions to similar medications
  • Participation in another clinical trial within the past 30 days
  • Mental conditions that could interfere with following study procedures
  • Use of live vaccines within 6 weeks before starting the study
  • Any condition that, in the opinion of the study doctor, would make participation unsafe
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Investigated drugs

Emapalumab is a medication that works by targeting and blocking a protein called interferon-gamma, which plays a role in inflammation. It is used to treat Macrophage Activation Syndrome (MAS), a severe inflammatory condition that can occur in patients with Still's disease and systemic lupus erythematosus. The medication helps control the overactive immune system response and reduce inflammation in the body.

What is already known about the treatment

Emapalumab - A monoclonal antibody administered through intravenous infusion, specifically designed to treat Macrophage Activation Syndrome (MAS) occurring in patients with Still's Disease and Systemic Lupus Erythematosus (SLE). This medication works by targeting and neutralizing interferon-gamma, a key protein involved in the inflammatory response that drives MAS, effectively reducing the excessive immune system activation characteristic of this condition. Currently under clinical investigation, emapalumab represents a targeted therapeutic approach for both pediatric and adult patients suffering from MAS, a serious complication that can occur in various autoimmune conditions, showing promise in controlling the life-threatening inflammatory response associated with this syndrome.

Investigated diseases

  • Macrophage Activation Syndrome (MAS)

    A severe inflammatory condition characterized by the abnormal activation and growth of immune system cells called macrophages. It can develop as a complication of other inflammatory diseases, causing fever, enlarged liver and spleen, and changes in blood cell counts.

  • Systemic Juvenile Idiopathic Arthritis (sJIA)

    A form of arthritis that affects children, causing inflammation in joints and other body parts. It typically begins with high fevers, rash, and joint pain, and can affect internal organs.

  • Adult Onset Still's Disease (AOSD)

    A rare inflammatory disorder that affects adults, similar to systemic juvenile idiopathic arthritis. It causes high fevers, salmon-colored rash, joint pain, and may affect various organs.

  • Systemic Lupus Erythematosus (SLE)

    A chronic autoimmune disease where the immune system attacks healthy tissues throughout the body. It can affect multiple organs, causing inflammation and various symptoms including joint pain, skin rashes, and fatigue.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2024-516153-52-00Protocol codeNI-0501-14Estimated enrolment41 patientsSponsorSwedish Orphan Biovitrum AG

sourced from the EU Clinical Trials Register and site verification

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