RecruitingPHASE3INTERVENTIONAL

A Study to Assess Efficacy and Safety of Efgartigimod PH20 SC PFS in Adult Participants With Graves' Disease

Graves' disease is an autoimmune condition where the body's defence system mistakenly attacks the thyroid gland, making it produce too many hormones. This can lead to symptoms like weight loss, shakiness, and feeling tired or anxious. In this Phase 3 clinical trial, researchers are testing a medicine called efgartigimod. It is given as an injection just under the skin. Efgartigimod is designed to reduce the specific antibodies that cause the thyroid to become overactive. The trial will compare the medicine to a dummy injection (placebo) to see if it is safe and effective. Adults who still have an overactive thyroid despite taking standard medications, such as carbimazole, may be able to join. The study lasts between 63 and 135 weeks, depending on how each person responds to the treatment.

At a glance

Status

Recruiting

Phase

PHASE3

Sponsor

argenx

Enrolment target

230

Start

10 Jun 2026

Estimated completion

01 May 2030

Graves' Disease Graves Disease

What is this study about?

Graves' disease is an autoimmune condition. Normally, your immune system protects you from illness. In Graves' disease, it mistakenly creates proteins called antibodies that tell your thyroid gland to work overtime. The thyroid sits in your neck and controls your metabolism. When it produces too much hormone, it can cause problems such as a racing heart, weight loss, heat intolerance, and trouble sleeping.

Standard treatments, like daily tablets, do not work well for everyone and may cause side effects. This study is exploring a new treatment approach. The study medicine, efgartigimod, targets and clears away the harmful antibodies driving the condition. Researchers want to find out whether lowering these antibodies can help bring thyroid hormone levels back to normal.

This is a Phase 3 trial, which means the medicine has already shown promise in earlier, smaller studies. Researchers now need to test it in a larger group of people to confirm how well it works and check for any side effects. By taking part, volunteers can help doctors understand if this could become a helpful new treatment option in the future.

Key takeaways

The trial tests a new injection designed to lower the antibodies that cause Graves' disease.
It is for adults whose Graves' disease is not fully controlled on tablets like carbimazole.
The study compares the active medicine against a placebo in its early stages.
Total participation lasts between 63 and 135 weeks, depending on your response.
Joining is voluntary, and you can withdraw at any time without losing your regular care.

Who may be eligible?

This trial is for adults aged 18 and older who have a confirmed diagnosis of Graves' disease and still have an overactive thyroid. To qualify, you must have been taking standard anti-thyroid tablets (such as carbimazole or methimazole) for at least three months, and your blood tests must still show elevated antibody levels and low thyroid-stimulating hormone (TSH).

You will not be able to join if your overactive thyroid is caused by something other than Graves' disease, or if you have previously had radioactive iodine treatment or surgery to remove your thyroid gland. You must also not have taken thyroid hormone replacement medicines (like levothyroxine) in the past six weeks.

In addition, people with certain complications cannot take part. This includes heart rhythm problems linked to Graves' disease that are not well controlled, or active thyroid eye disease that requires steroid treatment or surgery.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or older.
I have been diagnosed with Graves' disease.
I have taken carbimazole or methimazole for at least 3 months.
My thyroid is still overactive according to recent blood tests.
I have never had radioactive iodine therapy or thyroid removal surgery.
I do not have severe eye problems from Graves' disease needing steroids or surgery.

Answer every question to see your result.

What does participation involve?

If you take part, you will receive the study medicine or a dummy treatment (placebo) as an injection under the skin using a pre-filled syringe. The trial has three stages: a first part where neither you nor the doctors know if you receive the real medicine or placebo, a second monitoring stage, and a third open-label stage where all participants receive efgartigimod. You will visit the clinic regularly for blood tests, health checks, and safety monitoring. Depending on how your condition responds, your time in the study will range from about 15 months to just over two and a half years (63 to 135 weeks).

Potential risks and benefits

A potential benefit is that the study medicine may lower your antibody levels and help control your Graves' disease symptoms. You will also receive close medical attention and monitoring from specialist doctors throughout the trial. However, there is no guarantee the treatment will work for you, and in the first part you might receive a placebo. Like all medicines, efgartigimod can cause side effects, such as mild reactions around the injection site or an increased chance of minor infections because it lowers antibody levels. Taking part is completely your choice, and you can leave the study at any time without it affecting your usual NHS care.

Locations (35)

Profound Research LLC at Tri-City Primary Care
Verified postcode
Carlsbad, United States· Recruiting
Diabetes Associates Medical Group
Verified postcode
Orange, United States· Recruiting
Pasadena Clinical Trials
Verified postcode
Pasadena, United States· Recruiting
Havana Research Institute LLC.
Verified postcode
Pasadena, United States· Recruiting
San Jose Clinical Trials
Verified postcode
San Jose, United States· Recruiting
Northeast Florida Endocrine & Diabetes Associates (NEFEDA) - Orange Park Location
Verified postcode
Fleming Island, United States· Recruiting
The Center for Diabetes and Endocrine Care
Verified postcode
Fort Lauderdale, United States· Recruiting
University of Florida Jacksonville College of Medicine
Verified postcode
Jacksonville, United States· Recruiting
Ilumina Medical Research LLC
Verified postcode
Kissimmee, United States· Recruiting
Oceane 7 Medical & Research Center, Inc
Verified postcode
Miami, United States· Recruiting
Johnson County Clin-Trials, Inc.
Verified postcode
Lenexa, United States· Recruiting
Alliance for Multispecialty Research, LLC
Verified postcode
Wichita, United States· Recruiting

Common questions

What is efgartigimod?

Efgartigimod is a medicine that helps the body clear out certain antibodies. In Graves' disease, it aims to remove the antibodies that cause your thyroid to produce too much hormone.

Will I definitely get the active medicine?

Not right away. In the first part of the study, you have an equal chance of receiving either the active medicine or a dummy injection (placebo). In the final part, all participants receive the active medicine.

Can I keep taking my current thyroid tablets?

Participants must have been taking tablets like carbimazole for at least three months before joining. The study doctors will give you clear instructions on how your current medicines will be managed during the study.

How is the treatment given?

The medicine is given as a quick injection just under the skin (subcutaneously) using a pre-filled syringe, similar to how insulin is injected.

Do I have to pay to take part?

No. The study treatment and all trial-related tests are provided free of charge, and travel expenses to and from the clinic are often reimbursed.

How to find out more

Sabine Coppieters, MD

clinicaltrials@argenx.com 857-350-4834 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.