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Study on the Long-term Safety of Efgartigimod for Children with Generalized Myasthenia Gravis

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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 of a treatment for Generalized Myasthenia Gravis, a chronic autoimmune disease that causes muscle weakness. The treatment being tested is called efgartigimod, which is administered in two forms: intravenously (through a vein) and subcutaneously (under the skin). The study aims to evaluate how safe and well-tolerated these forms of efgartigimod are when given to children with this condition.

Participants in the study will receive either the intravenous or subcutaneous form of efgartigimod over a period of time. The study will monitor the occurrence and severity of any side effects, as well as changes in laboratory test results, vital signs, and other health indicators. The study will also look at the presence of any antibodies that might develop against efgartigimod or the enzyme used in the subcutaneous form, known as recombinant human hyaluronidase PH20.

The purpose of this study is to ensure that the treatment is safe for long-term use in children with Generalized Myasthenia Gravis. By carefully observing the effects of the treatment, researchers hope to gather important information that could lead to better management of this condition in the future.

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 a previous study, either ARGX-113-2006 or ARGX-113-2207. Agreement to join this study is required.

    Understanding the study requirements and providing written consent is necessary. This includes a willingness to follow the study procedures.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to ensure eligibility. This includes a negative pregnancy test for female participants of childbearing potential.

  3. Step 3

    Treatment administration

    The medication efgartigimod is administered in two forms: intravenous infusion and subcutaneous injection.

    The intravenous form is known as Vyvgart 20 mg/mL concentrate for solution for infusion.

    The subcutaneous form is known as Vyvgart 1 000 mg solution for injection.

  4. Step 4

    Monitoring and follow-up

    Regular monitoring is conducted to evaluate the safety and tolerability of the treatment.

    This includes checking for any adverse events, changes in laboratory test results, vital signs, height and weight, and electrocardiogram (ECG) results.

  5. Step 5

    Antibody testing

    Testing for the presence of antidrug antibodies against efgartigimod and antibodies against recombinant human hyaluronidase PH20 is performed.

  6. Step 6

    Completion of the study

    The study is estimated to end by September 30, 2028.

    Upon completion, a final assessment is conducted to ensure participant safety and gather final data.

Who can join the trial?

3 criteria

  • The participant must have completed a previous study called ARGX-113-2006 or ARGX-113-2207. This means they either finished the study and agreed to join this new study, or they qualify for more treatment but couldn't finish the previous study within its time limits.
  • The participant or their legally authorized representative must understand what the study involves and agree to it in writing. They should also be willing and able to follow the study's procedures.
  • If the participant is sexually active and can have children, they must use birth control as required by local rules for clinical studies. This applies to both males and females who are biologically capable of having children. Females must have a negative pregnancy test at the start of the study.
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Investigated drugs

  • Efgartigimod

    This medication is being tested to see if it is safe and well-tolerated when given to children with generalized myasthenia gravis. It is administered intravenously, which means it is given directly into a vein through an IV.

  • Efgartigimod PH20

    This is a form of efgartigimod that is administered subcutaneously, meaning it is injected under the skin. The trial is evaluating its safety and how well children with generalized myasthenia gravis tolerate this method of administration.

What is already known about the treatment

Efgartigimod – This medication is administered either intravenously or subcutaneously, depending on the formulation. It is currently being studied in clinical trials for its safety and tolerability in treating children with generalized myasthenia gravis. Efgartigimod works by reducing the levels of certain antibodies that attack the body's own tissues, helping to alleviate symptoms of the disease. It belongs to a class of drugs known as immunomodulators, which help regulate the immune system's activity.

Investigated diseases

Generalized Myasthenia Gravis – Generalized Myasthenia Gravis is a chronic autoimmune disorder that affects the communication between nerves and muscles, leading to muscle weakness. It occurs when the immune system mistakenly attacks the body's own tissues, specifically targeting the receptors that receive nerve signals. This results in fluctuating muscle weakness and fatigue, which can affect various muscle groups, including those responsible for eye movement, facial expression, and swallowing. The severity of symptoms can vary widely among individuals and may worsen with physical activity or stress. Over time, the condition can lead to more persistent muscle weakness, impacting daily activities and quality of life.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase IVTrial ID2023-507379-23-00Protocol codeARGX-113-2008Estimated enrolment31 patientsSponsorArgenx

sourced from the EU Clinical Trials Register and site verification

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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.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).