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Study on Long-term Safety and Efficacy of Efgartigimod in Adults with Active Idiopathic Inflammatory Myopathy Using a Drug Combination

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 the long-term safety and effectiveness of a treatment for people with idiopathic inflammatory myopathy, a condition that causes muscle inflammation and weakness. The treatment being tested is called efgartigimod, which is given as an injection under the skin. This study aims to understand how well this treatment works over a longer period and how well it is tolerated by participants.

Participants in the study will receive the treatment and be monitored for any side effects or changes in their health. The study will also look at how the treatment affects the use of other medications, such as glucocorticoids, which are often used to manage symptoms of the disease. The goal is to see if the treatment can help reduce the need for these medications over time.

Throughout the study, participants will have regular check-ups to monitor their health and the effectiveness of the treatment. This includes looking at various health indicators and assessing the overall improvement in their condition. The study will provide valuable information on the potential benefits and risks of using efgartigimod for treating idiopathic inflammatory myopathy.

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

    Participation begins after completing the previous study, ARGX-113-2007.

    Eligibility requires the ability to provide informed consent and comply with study requirements.

    Women of childbearing potential must have a negative pregnancy test before starting the study.

  2. Step 2

    Medication administration

    The study involves the administration of efgartigimod PH20 SC, a subcutaneous solution for injection.

    The medication is designed to assess long-term safety and tolerability in adults with active idiopathic inflammatory myopathy.

  3. Step 3

    Monitoring and assessments

    Regular monitoring of treatment-emergent adverse events, including any serious adverse events, is conducted.

    Vital signs, electrocardiogram (ECG), and laboratory parameters are checked for changes and abnormalities over time.

  4. Step 4

    Evaluation of treatment effects

    The study evaluates the reduction in prednisone dosage over time and the proportion of participants who discontinue corticosteroids by week 52.

    The total improvement score (TIS) and the proportion of TIS responders are assessed at weeks 12, 24, and 52.

  5. Step 5

    Disease activity and remission

    The percentage of participants with clinically inactive disease is measured, defined by no evidence of disease activity and normal creatine kinase values for at least 12 weeks.

    The study also measures the percentage of participants achieving remission, defined as clinically inactive disease for at least 24 weeks.

  6. Step 6

    Study duration

    The study is estimated to conclude by September 23, 2027.

    Recruitment for the study began on September 21, 2023.

Who can join the trial?

4 criteria

  • The patient must have completed a previous study called ARGX-113-2007.
  • The patient must be able to provide signed informed consent, which means they understand the study and agree to participate.
  • The patient must agree to follow contraceptive measures as required by local regulations. This means using methods to prevent pregnancy.
  • Women who can have children must have a negative urine pregnancy test before starting the study treatment.

Who cannot join the trial?

3 criteria

  • Patients who do not have Active Idiopathic Inflammatory Myopathy (IIM) cannot participate. This is a condition where the body's immune system attacks its own muscles, causing inflammation and weakness.
  • Patients who are not adults cannot participate. This means only individuals who are 18 years or older are eligible.
  • Patients who are part of a vulnerable population may not be eligible. Vulnerable populations include groups who might have difficulty giving informed consent or are at higher risk of harm.
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Investigated drugs

Efgartigimod PH20 SC is a medication being studied for its long-term safety, tolerability, and effectiveness in adults with active idiopathic inflammatory myopathy. This condition involves inflammation of the muscles, leading to muscle weakness. The medication is administered subcutaneously, meaning it is injected under the skin. The goal of this study is to determine how well patients tolerate the medication over an extended period and to observe any potential side effects or improvements in their condition.

What is already known about the treatment

Efgartigimod PH20 SC – This medication is administered subcutaneously, meaning it is injected under the skin. It is currently being studied in clinical trials to evaluate its long-term safety and effectiveness for treating active idiopathic inflammatory myopathy, a condition characterized by muscle inflammation. Efgartigimod works by modulating the immune system, specifically targeting and reducing the levels of certain antibodies that contribute to the disease. It is classified as an immunomodulatory agent, which means it helps regulate or normalize the immune system's response.

Investigated diseases

Idiopathic Inflammatory Myopathy – This is a group of diseases characterized by chronic muscle inflammation and weakness. The exact cause is unknown, but it involves the immune system attacking the body's own muscle tissues. Symptoms often begin with muscle weakness, particularly in the shoulders and hips, making it difficult to perform everyday activities. Over time, the weakness can progress, affecting other muscles and leading to fatigue and difficulty swallowing. Some individuals may also experience joint pain, skin rashes, or lung problems. The progression and severity of symptoms can vary widely among individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2022-502851-79-00Protocol codeARGX-113-2011Estimated enrolment240 patientsSponsorArgenx

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