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
Trial Snapshot
- Phase
- Phase 3
- Status
- Recruiting
- Sponsor
- argenx
- Enrollment
- 230
- Locations
- 23
- Primary Endpoint
- Percentage of participants who are euthyroid (fT3, fT4, and TSH within normal ranges) off ATDs at week 24 in part A
Study Overview
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
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
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.
Arms & Interventions
Part A - efgartigimod PH20 SC PFS
Participants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.
Intervention: Efgartigimod PH20 SC (Biological)
Part A - placebo PH20 SC PFS
Participants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part A double-blinded treatment period.
Intervention: Placebo PH20 SC (Other)
Part B - efgartigimod PH20 SC PFS
Participants will receive efgartigimod PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.
Intervention: Efgartigimod PH20 SC (Biological)
Part B - placebo PH20 SC PFS
Participants will receive placebo PH20 SC Via Prefilled Syringe (PFS) during the part B treatment period.
Intervention: Placebo PH20 SC (Other)
Part C - efgartigimod PH20 SC PFS
Participants will receive efgartigimod PH20 SC PFS in the part C open-label treatment period
Intervention: Efgartigimod PH20 SC (Biological)
Outcomes
Primary Outcomes
Percentage of participants who are euthyroid (fT3, fT4, and TSH within normal ranges) off ATDs at week 24 in part A
Time Frame: Up to 24 weeks (part A)
Free triiodothyronine: \[fT3\]; free thyroxine: \[fT4\]; ATDs: antithyroid drugs
Secondary Outcomes
- 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 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))
- Time to becoming euthyroid off ATDs and TRAb seronegative(Up to 24 weeks (part A) + up to 135 weeks)
- Time to becoming euthyroid and receiving an ATD dose of MMI ≤5 mg/day or CBZ ≤7.5 mg/day (part A)(Up to 24 weeks (Part A))
- Time to becoming euthyroid(Up to 24 weeks (part A) + up to 135 weeks)
- Time to having TSH within normal ranges among participants who have TSH lower than the LLN at baseline (part A)(Up to 24 weeks (part A))
- Percentage of participants who remain euthyroid without ATDs(Up to 74 weeks (part B))
- Percentage of participants who remain euthyroid without ATDs and without efgartigimod PH20 SC PFS for 6, 12, and 18 months(Up to 74 weeks (part B) + up to 135 weeks)
- Percentage of participants who remain euthyroid without ATDs and without efgartigimod PH20 SC PFS(Up to 72 weeks (part C))
- Incidence of AEs and SAEs(Up to 135 weeks)
- Change in ThyPRO-39 over time(Up to 135 weeks)
- Change in PROMIS-PF10a over time(Up to 135 weeks)
- Efgartigimod serum concentrations over time(Up to 24 weeks (part A) + 72 weeks (part C))
- Percentage change from baseline in total IgG levels in serum over time(Up to 98 weeks)
- Percentage change from baseline in TRAb serum levels over time(Up to 135 weeks)
- Incidence of ADA against efgartigimod in serum(Up to 24 weeks (part A) + up to 135 weeks)
- Incidence of antibodies against rHuPH20 in plasma(Up to 24 weeks (part A) + Up to 135 weeks)
- Incidence of NAb against efgartigimod in serum and rHuPH20 in plasma(Up to 24 weeks (part A) + up to 135 weeks)