A Study to Assess the Long-term Safety and Efficacy of a Subcutaneous Formulation of Efgartigimod in Adults With Active Idiopathic Inflammatory Myopathy

Phase 3

• Conditions: Myositis; Polymyositis; Dermatomyositis; Immune-Mediated Necrotizing Myopathy; Antisynthetase Syndrome; Active Idiopathic Inflammatory Myopathy
• Interventions: Biological: EFG PH20 SC

• Registration Number: NCT05979441
• Lead Sponsor: argenx

Brief Summary

The purpose of this study is to measure the long-term safety and tolerability of efgartigimod PH20 SC in adult participants with IIM who previously participated in ARGX-113-2007. Secondary objectives include efficacy measures of efgartigimod PH20 SC in participants with IIM.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-07-28
• Study First Submitted QC: 2023-07-28
• Study First Posted: 2023-08-07
• Study Start: 2023-09-12
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-19
• Last Update Posted: 2025-05-22
• Primary Completion: 2027-09
• Study Completion: 2027-09

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 240

Inclusion Criteria

• Has completed trial ARGX-113-2007
• Being capable of providing signed informed consent and complying with protocol requirements
• Agrees to use contraceptive measures consistent with local regulations and women of childbearing potential must have a negative urine pregnancy test at baseline before receiving the investigational medicinal product

Exclusion Criteria

• Intention to have major surgery during the study period; or any other medical condition that has arisen since enrollment in study ARGX-113-2007, that in the investigator's opinion, would confound the results of the study or put the participant at undue risk
• Known hypersensitivity reaction to investigational medicinal product or 1 of its excipients Development of any malignancy, either new or recurrent, other than basal cell carcinoma of the skin, regardless of relatedness
• Permanent discontinuation of IMP in ARGX-113-2007, or met the permanent discontinuation criteria at the rollover visit
• Diagnosis with a deselected subtype of myositis based on the analysis of the phase 2 stage data in ARGX-113-2007, unless the investigator determines that the participant is benefiting from IMP as defined by a score of "much better" or "moderately better" on the 'Clinical Global Impression of Change' and 'Patient Global
• Impression of Change' assessments for at least 12 weeks, and that enrolling in the study is in the participant's best interest

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
EFG PH20 SC	EFG PH20 SC	participants receiving efgartigimod PH20 SC on top of background treatment

Primary Outcome Measures

Name	Time	Method
Incidence treatment-emergent adverse events and adverse event of special interest	Up to 60 weeks

Secondary Outcome Measures

Name	Time	Method
Composite Glucocorticoid Toxicity Index (C-GTI) comprising the Aggregate Improvement Score (AIS) and the Cumulative Worsening Score (CWS)	Up to 52 weeks
Prednisone dose reduction (average monthly dose)	Up to 52 weeks
Percentage of participants with clinically inactive disease	up to 52 weeks
Proportion of TIS responders (minimal, moderate, major)	up to 52 weeks
Percentage of participants with remission, defined as a clinically inactive disease for at least 24 weeks	up to 52 weeks
Total improvement score (TIS)	Up to 52 weeks	measured on a \[0,100\] scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Proportion of participants who discontinue corticosteroids	Up to 52 weeks
Individual core set measures (CSMs) of the TIS	up to 52 weeks	measured on a \[0,100\] scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).

Trial Locations

Locations (51)

Neuromuscular Clinical and Research Center - Neurology; 🇺🇸 Phoenix, Arizona, United States

Attune Health Research, Inc; 🇺🇸 Beverly Hills, California, United States

UCI Health - ALS and Neuromuscular Center - Neurology; 🇺🇸 Orange, California, United States

UCSF Health - ALS and Neurodegenerative Disease Center - Dermatology; 🇺🇸 San Francisco, California, United States

UF Health - Rheumatology Medical Specialties Medical Plaza; 🇺🇸 Gainesville, Florida, United States

Mayo Clinic - Florida - Neurology; 🇺🇸 Jacksonville, Florida, United States

Emory Healthcare - Emory Clinic - Rheumatology; 🇺🇸 Atlanta, Georgia, United States

Northwestern Medicine - Northwestern Memorial Hospital; 🇺🇸 Chicago, Illinois, United States

Northwell Health Physician Partners Rheumatology; 🇺🇸 Great Neck, New York, United States

Oregon Health and Science University; 🇺🇸 Portland, Oregon, United States

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