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Taking peoplePhase 3

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

Key facts

Who runs it
argenx
Where
Angers, Bron, Nantes, and Paris, FranceSee the 4 sitesAlso in 16 other countries, 97 sites
Status
Recruiting
Phase
Phase 3
People taking part
230 people, planned
Started
10 Jun 2026
Expected to end
May 2030
Type of study
Interventional, 5 groupsOne group gets a placebo (a dummy treatment), for comparison.
Treatments tested
  • efgartigimod PH20 SC
  • Placebo PH20 SC
Record updated
3 November 2026

Who can take part

Age
18 years and older
Sex
Women and men
Healthy volunteers
Cannot take part

The registry criteria, word for word

Show all 9 criteriaShow less

Who can take part

  • Is at least 18 years of age and the local legal age of consent for clinical studies when signing the ICF
  • Has a documented diagnosis of GD with TRAb (anti-thyrotropin receptor antibody) levels >=ULN (upper limit of normal) at screening
  • Has active hyperthyroidism due to GD with TSH (thyroid-stimulating hormone) <0.1 mIU/L at screening
  • Has been treated with MMI (methimazole) or CBZ (carbimazole) for at least 3 months before screening

Who cannot take part

  • History of RAI (radioactive iodine) therapy or received a total thyroidectomy
  • T3- or T4-containing medication or supplement (eg, levothyroxine, liothyronine, desiccated thyroid preparations, or thyroid-support supplements) received <6 weeks before screening
  • History of hyperthyroidism not caused by GD (eg, toxic adenoma or toxic multinodular goiter)
  • Any complication of hyperthyroidism or underlying medical condition that would put the participant at undue risk. This includes arrhythmia or tachyarrhythmia related to GD, such as atrial fibrillation or atrial flutter not sufficiently controlled with medications
  • Graves' orbitopathy/Thyroid Eye Disease (GO/TED) requiring systemic therapy (eg, corticosteroids), orbital injections, orbital surgery, or orbital radiation, or expected immediate surgical intervention and/or planned corrective surgery/irradiation or medical therapy during the study

Where in France

Also in 16 other countries, 97 sites

  • Centre Hospitalier Universitaire D'AngersAngers, FranceNo longer taking part
  • Hospices Civils de LyonBron, FranceNo longer taking part
  • Centre Hospitalier Universitaire de NantesNantes, FranceNo longer taking part
  • Assistance Publique Hopitaux de ParisParis, FranceNo longer taking part

About the trial

What the trial wants to find out

The main purpose of this study is to look at how efgartigimod affects thyroid function in adults with Graves' Disease (GD). The study will also check whether efgartigimod is safe and well tolerated. It will look at how efgartigimod is distributed and eliminated in the body, how it changes antibody levels, and how the immune system responds to it.

Read full original descriptionShow less

The study consists of a part A double-blinded treatment period, a part B treatment/observation period and a part C open-label treatment/observation period. During the part A and part B treatment periods, participants will receive efgartigimod PH20 SC via Prefilled Syringe (PFS) or placebo. During the part C open-label treatment period, participants will receive efgartigimod PH20 SC PFS. Participation in the different parts of the study will depend on the participant's response to treatment.

The total study duration for participants ranges from 63 to 135 weeks, depending on the response to treatment.

More information can be found here: https://clinicaltrials.argenx.com/vitalithy

The 5 groups in the trial

  • Part A - efgartigimod PH20 SC PFSTreatment being tested

    Participants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.

    Treatment: efgartigimod PH20 SC

  • Part A - placebo PH20 SC PFSPlacebo, for comparison

    Participants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.

    Treatment: Placebo PH20 SC

  • Part B - efgartigimod PH20 SC PFSTreatment being tested

    Participants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.

    Treatment: efgartigimod PH20 SC

  • Part B - placebo PH20 SC PFSTreatment being tested

    Participants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.

    Treatment: Placebo PH20 SC

  • Part C - efgartigimod PH20 SC PFSTreatment being tested

    Participants, will receive efgartigimod PH20 SC PFS in the part C open-label treatment period

    Treatment: efgartigimod PH20 SC

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

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Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A Phase 3, Randomized, Double-Masked, Placebo-Controlled, Multicenter Study Evaluating the Efficacy and Safety of Efgartigimod PH20 SC PFS in Adult Participants With Graves' Disease Inadequately Controlled With Antithyroid Drugs
Record updated
3 November 2026