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

argenx

Status and phase: Enrolling; Phase 3

Conditions: Graves Disease; Graves' Disease

Treatments: Biological: Efgartigimod PH20 SC; Other: Placebo PH20 SC

Study type: Interventional

Funder types: Industry

Identifiers

NCT07570316

2025-524223-42-00 (EU Trial (CTIS) Number)

ARGX-113-25-GRD-3002

Details and patient eligibility

About

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.

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

Enrollment: 230 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 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.

Exclusion criteria

• History of hyperthyroidism not caused by GD (eg, toxic adenoma or toxic multinodular goiter).
• 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.
• 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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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230 participants in 5 patient groups, including a placebo group

Part A - efgartigimod PH20 SC PFS

Experimental group

Description:

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

Treatment:

Biological: Efgartigimod PH20 SC

Part A - placebo PH20 SC PFS

Placebo Comparator group

Description:

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

Treatment:

Other: Placebo PH20 SC

Part B - efgartigimod PH20 SC PFS

Experimental group

Description:

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

Treatment:

Biological: Efgartigimod PH20 SC

Part B - placebo PH20 SC PFS

Experimental group

Description:

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

Treatment:

Other: Placebo PH20 SC

Part C - efgartigimod PH20 SC PFS

Experimental group

Description:

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

Treatment:

Biological: Efgartigimod PH20 SC