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Study of Efgartigimod for Adults with Thyroid Eye Disease

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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 Thyroid Eye Disease (TED), a condition often associated with autoimmune thyroid disorders like Graves' disease or Hashimoto's thyroiditis. The study will evaluate a treatment called Efgartigimod, which is administered as a solution for injection using a pre-filled syringe. Efgartigimod is a type of protein designed to interact with the immune system, specifically targeting a receptor known as FcRn. The trial will compare the effects of Efgartigimod with a placebo to understand its effectiveness and safety.

The purpose of the study is to assess how well Efgartigimod works in reducing symptoms of Thyroid Eye Disease, particularly focusing on the reduction of eye bulging, known as proptosis, over a 24-week period. Participants in the study will receive either Efgartigimod or a placebo through subcutaneous injections, which means the injection is given under the skin. The study will monitor changes in eye symptoms and overall quality of life during this time.

Participants will be adults diagnosed with active, moderate-to-severe Thyroid Eye Disease. The study will involve regular visits to monitor the effects of the treatment and ensure the safety and well-being of the participants. The trial aims to provide valuable information on whether Efgartigimod can be a beneficial treatment option for those affected by this condition.

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

    Joining the study

    Upon joining the study, the participant must be at least 18 years old and have a diagnosis of active, moderate-to-severe thyroid eye disease (TED) associated with autoimmune thyroid conditions.

    The participant must have experienced the onset of active TED symptoms within 12 months before joining the study and have normal thyroid function or mild thyroid issues that are under control.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to confirm eligibility, including a review of medical history and a physical examination.

    Participants of child-bearing potential will undergo a blood pregnancy test at screening and a urine pregnancy test before receiving the study drug.

  3. Step 3

    Treatment period

    The treatment involves receiving efgartigimod or a placebo, administered as a solution for injection using a pre-filled syringe.

    The medication is given subcutaneously, which means it is injected under the skin.

    The treatment period is double-blind, meaning neither the participant nor the study team knows whether the participant is receiving efgartigimod or the placebo.

  4. Step 4

    Monitoring and assessments

    Throughout the study, regular monitoring and assessments will be conducted to evaluate the efficacy and safety of the treatment.

    The primary goal is to assess the percentage of participants who are proptosis responders at week 24 of the treatment period.

  5. Step 5

    Completion of treatment

    At the end of the 24-week treatment period, final assessments will be conducted to measure changes in proptosis and quality of life scores.

    The study aims to determine the effectiveness of efgartigimod in reducing symptoms of thyroid eye disease.

Who can join the trial?

6 criteria

  • The participant is at least 18 years old.
  • The participant is capable of providing signed informed consent, which means they understand the study and agree to participate, and can follow the study's requirements.
  • The participant has a doctor's diagnosis of active, moderate-to-severe **Thyroid Eye Disease (TED)**, which is related to autoimmune thyroid conditions like **Graves' disease** or **Hashimoto's thyroiditis**, affecting the most severely impacted eye.
  • The participant has experienced symptoms of active TED within 12 months before the screening for the study.
  • The participant must have normal thyroid function, meaning their thyroid is working properly, or have mild **hypothyroidism** (underactive thyroid) or **hyperthyroidism** (overactive thyroid) at the time of screening. Efforts should be made to correct any mild thyroid issues quickly and maintain normal thyroid function throughout the study.
  • The participant agrees to use birth control as per local regulations. People who can have children must have a negative blood pregnancy test at screening and a negative urine pregnancy test before receiving the study drug.

Who cannot join the trial?

10 criteria

  • Patients with other serious health conditions that might interfere with the study.
  • Patients who are currently participating in another clinical trial.
  • Patients who have had recent surgery or plan to have surgery during the study period.
  • Patients who are pregnant or breastfeeding.
  • Patients with a history of drug or alcohol abuse.
  • Patients who have an allergy to the study medication or its ingredients.
  • Patients who have received certain treatments for Thyroid Eye Disease (TED) recently.
  • Patients with uncontrolled high blood pressure or diabetes.
  • Patients with certain eye conditions that are not related to TED.
  • Patients who have a history of certain types of cancer.
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Investigated drugs

Efgartigimod PH20 SC is a medication being studied for its effectiveness in treating Thyroid Eye Disease. It is administered using a prefilled syringe. The trial aims to assess how well this medication works, its safety, how the body processes it, and its potential to cause an immune response.

What is already known about the treatment

Efgartigimod PH20 SC – This medication is administered subcutaneously using a prefilled syringe. It is currently being studied in a Phase 3 clinical trial for its effectiveness in treating Thyroid Eye Disease (TED). The main therapeutic indication is to reduce symptoms associated with TED, such as eye bulging. 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.

Investigated diseases

Thyroid Eye Disease (TED) – This is an autoimmune condition where the immune system mistakenly attacks the tissues around the eyes, often associated with thyroid disorders. It leads to inflammation and swelling, causing the eyes to bulge outward, a condition known as proptosis. Patients may experience redness, irritation, and discomfort in the eyes, along with double vision or vision changes. As the disease progresses, it can lead to further complications such as restricted eye movement and eyelid retraction. The severity of symptoms can vary, and the disease may have periods of activity and inactivity. TED is often linked to Graves' disease, but it can occur in other thyroid conditions as well.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-509197-35-00Protocol codeARGX-113-2301Estimated enrolment123 patientsSponsorArgenx

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