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Study of Efgartigimod PH20 SC 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 that affects the eyes and is often associated with autoimmune thyroid conditions 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 that is designed to help manage the symptoms of TED. Participants in the study will receive either efgartigimod or a placebo, which is a substance with no active medication.

The purpose of the study is to assess how effective efgartigimod is in treating TED by looking at the change in eye symptoms over a 24-week period. The study will involve regular check-ups and assessments to monitor the participants' progress and any changes in their condition. The main focus will be on the reduction of eye bulging, known as proptosis, and improvements in the quality of life related to eye health. Participants will be randomly assigned to receive either the active treatment or the placebo, and neither the participants nor the researchers will know who is receiving which treatment during the study period.

Throughout the study, participants will be closely monitored for any side effects or changes in their condition. The study aims to provide valuable information on the safety and effectiveness of efgartigimod for people with TED, potentially leading to better treatment options in the future. The trial is expected to continue until 2027, with recruitment starting in 2024.

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 such as Graves' disease or Hashimoto's thyroiditis.

    The participant must have experienced the onset of active TED symptoms within 12 months before the screening and have normal thyroid function or mild hypo or hyperthyroidism that is controlled.

  2. Step 2

    Initial screening

    The participant undergoes an initial screening to confirm eligibility, including a blood pregnancy test for those of child-bearing potential, which must be negative.

    The participant must agree to use birth control consistent with local regulations throughout the study.

  3. Step 3

    Treatment period

    The treatment involves receiving efgartigimod or a placebo, administered subcutaneously using a prefilled syringe.

    The treatment is conducted over a period of 24 weeks, during which the participant receives regular doses as per the study protocol.

  4. Step 4

    Monitoring and assessments

    Throughout the 24-week treatment period, the participant's response to the treatment is monitored, focusing on changes in proptosis (eye bulging) and quality of life.

    Assessments include measuring proptosis and evaluating any changes in symptoms such as double vision (diplopia).

  5. Step 5

    End of treatment evaluation

    At the end of the 24-week treatment period, the participant's response to the treatment is evaluated to determine the percentage of proptosis responders.

    Additional evaluations include changes in proptosis measurement and quality of life scores from baseline to the end of the treatment period.

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.
  • 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**. This should be for the eye that is most affected.
  • The participant has had symptoms of active TED starting 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 keep thyroid function normal throughout the study.
  • The participant agrees to use birth control as per local rules. 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 who have a different eye condition that is not related to **Thyroid Eye Disease (TED)**.
  • Patients who are not within the specified age range for the study.
  • Patients who are not able to follow the study procedures or attend the required visits.
  • Patients who have a medical condition that could interfere with the study results.
  • Patients who are currently participating in another clinical trial.
  • Patients who have had a recent surgery or are planning to have surgery during the study period.
  • Patients who are pregnant or breastfeeding.
  • Patients who have a history of allergic reactions to the study medication or similar medications.
  • Patients who have a serious illness that could affect their participation in the study.
  • Patients who have a history of drug or alcohol abuse.
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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, leading to inflammation and swelling. It often occurs in people with thyroid disorders, particularly Graves' disease. The disease can cause symptoms such as bulging eyes, redness, and discomfort. As it progresses, it may lead to double vision and difficulty moving the eyes. The severity of symptoms can vary, and the disease may have periods of activity and remission. Over time, the inflammation can lead to changes in the appearance of the eyes and affect vision.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-509198-22-00Protocol codeARGX-113-2309Estimated enrolment123 patientsSponsorArgenx

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