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Clinical trial Phase 3 Interventional Ages 18 and up

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

Run by argenx · NCT05979441 · Data updated 2026-11-12

Enrolling by invitation only. This study is not taking new participants. Its registered completion date is 2028-09.

The main purpose of this study is to measure the long-term safety and tolerability of efgartigimod PH20 SC in adult participants with Idiopathic Inflammatory Myopathy (IIM) who previously participated in ARGX-113-2007. The study consists of a treatment period where participants will receive efgartigimod PH20 SC for up to 51 months. The treatment period will be followed by a treatment-free safety follow-up period of 56 days.

Quick facts

PhasePhase 3
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment240 (estimated)
Sponsorargenx
Industry-sponsored
Drugs / interventionsEfgartigimod PH20 SC
Locations92 sites (Argentina, Austria, Belgium, Bulgaria, China, Cyprus, Czechia, Denmark and more)
Trial IDNCT05979441 on ClinicalTrials.gov

Who can join: the full rules

Show full inclusion / exclusion criteria 
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 study drug

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 the study drug or 1 of its excipients
* Development of any malignancy, either new or recurrent, other than basal cell carcinoma of the skin, regardless of relatedness

Where it's running

  • 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
  • Yale Cancer Center-Yale University School Of Medicine
    New Haven, Connecticut, United States
  • UF Health - Rheumatology Medical Specialties Medical Plaza
    Gainesville, Florida, United States
Show 44 more locations
  • Mayo Clinic - Florida - Neurology
    Jacksonville, Florida, United States
  • University of South Florida (USF) - Morsani Center (USF Health Carol and Frank Morsani Center for Advanced Healthcare)
    Tampa, Florida, United States
  • Emory Healthcare - Emory Clinic - Rheumatology
    Atlanta, Georgia, United States
  • Northwestern Medicine - Northwestern Memorial Hospital
    Chicago, Illinois, United States
  • John Hopkins Medicine - Johns Hopkins Myositis Center
    Baltimore, Maryland, United States
  • Northwell Health Physician Partners Rheumatology
    Great Neck, New York, United States
  • University of North Carolina (UNC) School of Medicine
    Chapel Hill, North Carolina, United States
  • The Ohio State University
    Columbus, Ohio, United States
  • Oregon Health and Science University
    Portland, Oregon, United States
  • University of Pittsburgh Medical Center
    Pittsburgh, Pennsylvania, United States
  • Austin Neuromuscular Center (National Neuromuscular Research Institute, PLLC)
    Austin, Texas, United States
  • Nerve And Muscle Center Of Texas
    Houston, Texas, United States
  • Framingham Centro Medico
    La Plata, Argentina
  • Centro Dermatologico Schejtman
    San Miguel, Argentina
  • Centro Medico Privado de Reumatologia
    San Miguel de Tucumán, Argentina
  • Tirol Kliniken - A.o. Landeskrankenhaus Innsbruck - Neurology
    Innsbruck, Austria
  • AZ Sint-Lucas - Campus Sint-Lucas - Neurology
    Ghent, Belgium
  • Universitair Ziekenhuis Leuven Gasthuisberg Campus
    Leuven, Belgium
  • Medical Centre Artmed
    Plovdiv, Bulgaria
  • Multiprofile hospital for active treatment Kaspela EOOD
    Plovdiv, Bulgaria
  • Nanfang Hospital, Southern Medical University
    Guangzhou, Guangdong, China
  • Nanjing University Medical School - Taikang Xianlin Drum Tower Hospital (Nanjing Drum Tower Hospital)
    Nanjing, Jingsu, China
  • Peking University Third Hospital
    Beijing, China
  • Peking Union Medical College Hospital
    Beijing, China
  • Sichuan Provincial Academy of Medical Sciences and Sichuan Provincial People's Hospital
    Chengdu, China
  • Shanghai Jiao Tong University School of Medicine - Renji Hospital - Shanghai Institute of Digestive Disease (SIDD)
    Shanghai, China
  • Huashan Hospital Affiliated to Fudan University
    Shanghai, China
  • China Medical University (CMU) - First Affiliated Hospital
    Shenyang, China
  • First Affiliated Hospital (Henan Medical University - First Affiliated Hospital)-Zhengzhou University
    Zhengzhou, China
  • Cyprus Institute of Neurology and Genetics
    Nicosia, Cyprus
  • Revmatologicky Ustav
    Prague, Czechia
  • Copenhagen University Hospital-Rigshospitalet University Hospital
    Copenhagen, Denmark
  • Reference Center Neuro-Muscular Diseases - CHU Paris Group Hospitalier La Pitie Salpetriere-Charles Foix
    Paris, France
  • Aversi Clinic
    Tbilisi, Georgia
  • LLC MediClub Georgia
    Tbilisi, Georgia
  • New Hospitals
    Tbilisi, Georgia
  • The First Medical Center
    Tbilisi, Georgia
  • Charite Universitaetsmedizin Berlin - Campus Charite Mitte (CCM) - Rheumatology
    Berlin, Germany
  • Universitaetsklinikum Hamburg-Eppendorf
    Hamburg, Germany
  • Rheumazentrum Ruhrgebiet
    Herne, Germany
  • Universitatsmedizin Mannheim GmbH
    Mannheim, Germany
  • Universitaetsklinikum Tuebingen (UKT)
    Tübingen, Germany
  • Klinikum der Universitaet Ulm
    Ulm, Germany
  • National and Kapodistrian University of Athens - School of Health Sciences - Faculty of Medicine
    Athens, Greece

+42 more sites. See ClinicalTrials.gov for the full list.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
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Last reviewed 2026-11-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.