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

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

NCT Number	NCT07570316
Lead Sponsor	argenx
Conditions	Graves' Disease, Graves Disease
Enrollment	230 participants
Start Date	2026-06-10
Primary Completion	2028-06 (estimated)
Study Completion	2030-05 (estimated)
Updated on ClinicalTrials.gov	2026-08-12