A Phase 3, Randomized, Double-Masked, Placebo-Controlled, Multicenter Study to Evaluate the Efficacy, Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Efgartigimod PH20 SC Administered by Prefilled Syringe in Adult Participants With Thyroid Eye Disease

Status

Completed

Phases

Phase 3

Study type

Interventional

Source

EU CTIS

Registry ID

CTIS2023-509198-22-00

Acronym

ARGX-113-2309

Enrollment

Registered

2024-09-23

Start date

2024-10-21

Completion date

2025-12-15

Last updated

2025-12-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Thyroid Eye Disease (TED)

Brief summary

Percentage of participants who were proptosis responders at Double-Blind treatment period (DBTP) week 24.

Detailed description

Change in proptosis measurement in the study eye from baseline to Double-Blind Treatment Period (DBTP) week 24, Change in the total GO-QoL score from baseline to Double-Blind Treatment Period (DBTP) week 24, Percentage of participants with a resolution of diplopia (responders) at Double-Blind Treatment Period (DBTP) week 24.

Interventions

DRUGVyvgart 1 000 mg solution for injection in pre-filled syringe

DRUGPlacebo for efgartigimod

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Design outcomes

Primary

Measure	Time frame
Percentage of participants who were proptosis responders at Double-Blind treatment period (DBTP) week 24.	—

Secondary

Measure	Time frame
Change in proptosis measurement in the study eye from baseline to Double-Blind Treatment Period (DBTP) week 24, Change in the total GO-QoL score from baseline to Double-Blind Treatment Period (DBTP) week 24, Percentage of participants with a resolution of diplopia (responders) at Double-Blind Treatment Period (DBTP) week 24.	—

Countries

Austria, Bulgaria, France, Germany, Italy, Latvia, Poland, Slovenia, Spain, Sweden

Outcome results

None listed

Source: EU CTIS · Data processed: Feb 4, 2026