A Study to Assess Efficacy and Safety of Efgartigimod PH20 SC PFS in Adult Participants With Graves' Disease
VitaliThy
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
2 other identifiers
interventional
230
2 countries
18
Brief Summary
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
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for phase_3
Started Jun 2026
Typical duration for phase_3
18 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
April 30, 2026
CompletedFirst Posted
Study publicly available on registry
May 6, 2026
CompletedStudy Start
First participant enrolled
June 10, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 1, 2028
ExpectedStudy Completion
Last participant's last visit for all outcomes
May 1, 2030
July 8, 2026
July 1, 2026
2 years
April 30, 2026
July 7, 2026
Conditions
Outcome Measures
Primary Outcomes (1)
Percentage of participants who are euthyroid (fT3, fT4, and TSH within normal ranges) off ATDs at week 24 in part A
Free triiodothyronine: \[fT3\]; free thyroxine: \[fT4\]; ATDs: antithyroid drugs
Up to 24 weeks (part A)
Secondary Outcomes (20)
Time to becoming euthyroid off ATDs in part A
Up to 24 weeks (part A)
Percentage of participants who are euthyroid and receiving MMI ≤5 mg/day or CBZ ≤7.5 mg/day at week 24 in part A
Up to 24 weeks (part A)
Percentage of participants with fT3 and fT4 levels below the ULN off ATDs at week 24 in part A
Up to 24 weeks (part A)
Percentage of participants who are euthyroid off ATDs and TRAb seronegative at week 24 in part A
Up to 24 weeks (part A)
Time to becoming euthyroid off ATDs and TRAb seronegative
Up to 24 weeks (part A) + up to 135 weeks
- +15 more secondary outcomes
Study Arms (5)
Part A - efgartigimod PH20 SC PFS
EXPERIMENTALParticipants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.
Part A - placebo PH20 SC PFS
PLACEBO COMPARATORParticipants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.
Part B - efgartigimod PH20 SC PFS
EXPERIMENTALParticipants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.
Part B - placebo PH20 SC PFS
EXPERIMENTALParticipants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.
Part C - efgartigimod PH20 SC PFS
EXPERIMENTALParticipants will receive efgartigimod PH20 SC PFS in the part C open-label treatment period
Interventions
Subcutaneous injection of placebo PH20 via Prefilled Syringe (PFS)
Subcutaneous injection of Efgartigimod PH20 Via Prefilled Syringe (PFS)
Eligibility Criteria
You may qualify if:
- 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.
You may not qualify if:
- 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.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- argenxlead
Study Sites (18)
Diabetes Associates Medical Group
Orange, California, 92868, United States
Havana Research Institute LLC.
Pasadena, California, 91105, United States
Northeast Florida Endocrine & Diabetes Associates (NEFEDA) - Orange Park Location
Fleming Island, Florida, 32003, United States
The Center for Diabetes and Endocrine Care
Fort Lauderdale, Florida, 33312, United States
Ilumina Medical Research LLC
Kissimmee, Florida, 34744, United States
Johnson County Clin-Trials, Inc.
Lenexa, Kansas, 66219, United States
Metro Detroit Endocrinology Center
Dearborn, Michigan, 48126, United States
Profound Research
Farmington Hills, Michigan, 48334, United States
Endocrine Associates of West Village PC
New York, New York, 10016, United States
Research Institute of Dallas
Dallas, Texas, 75231, United States
Juno Research
Houston, Texas, 77040, United States
Tekton Research Irving
Irving, Texas, 75039, United States
Biopharma Informatic, LLC
McAllen, Texas, 78503, United States
Tekton Research - McKinney
McKinney, Texas, 75069, United States
Southern Endocrinology Associates PA
Mesquite, Texas, 75149, United States
Consano Clinical Research
Shavano Park, Texas, 78231, United States
New Hospitals
Tbilisi, 0114, Georgia
LLC Todua Clinic
Tbilisi, 0119, Georgia
Related Links
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
April 30, 2026
First Posted
May 6, 2026
Study Start
June 10, 2026
Primary Completion (Estimated)
June 1, 2028
Study Completion (Estimated)
May 1, 2030
Last Updated
July 8, 2026
Record last verified: 2026-07
Data Sharing
- IPD Sharing
- Will not share