A Phase 3 interventional study of Efgartigimod PH20 SC in Myositis, Active Idiopathic Inflammatory Myopathy and Dermatomyositis, sponsored by argenx. Enrolling by invitation at 92 sites in 29 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by argenx · Phase 3, Interventional, and Treatment
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.
184 studies on the registry are indexed under Dermatomyositis; 63 are open to participants now.
This study's planned enrollment of 240 is above the median of 35 across 130 interventional studies indexed under Dermatomyositis.
Browse Dermatomyositis studies →argenx is the lead sponsor of 87 studies on the registry; 29 are open to participants now.
Of its 22 completed or terminated interventional studies of FDA-regulated products, 16 (73%) have results posted.
Compared within Dermatomyositis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Myositis. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receiving efgartigimod PH20 subcutaneously
Biological: Efgartigimod PH20 SC
Drug pages: Efgartigimod alfa · Hyaluronidase (human recombinant)
Subcutaneous injection of Efgartigimod PH20 given by vials or prefilled syringe (PFS)
Incidence of AEs, SAEs and AESIs over time
AE : adverse event ; SAE : serious adverse event ; AESI : adverse event of special interest.
Time frame: Up to 53 months
C-GTI comprising the AIS over time
The Composite Glucocorticoid Toxicity Index (C-GTI) serves as a primary instrument to capture toxicities likely caused by glucocorticoid exposure and enables monitoring of long-term tolerability of glucocorticoids during prolonged use. The Aggregate Improvement Score (AIS) is an analytical scores generated from the weighted C-GTI. The AIS can be used to assess whether a new therapy is effective in reducing glucocorticoid toxicity over time; higher AIS scores are associated with less toxicity.
Time frame: Up to 51 months
C-GTI comprising the CWS over time
The Composite Glucocorticoid Toxicity Index (C-GTI) serves as a primary instrument to capture toxicities likely caused by glucocorticoid exposure and enables monitoring of long-term tolerability of glucocorticoids during prolonged use. The Cumulative Worsening Score (CWS) is an analytical score generated from the weighted C-GTI. The CWS is designed to assess cumulative glucocorticoid toxicity; higher scores indicate increased steroid toxicity.
Time frame: Up to 51 months
C-GTI comprising the GTI-MD over time
The Composite Glucocorticoid Toxicity Index (C-GTI) serves as a primary instrument to capture toxicities likely caused by glucocorticoid exposure and enables monitoring of long-term tolerability of glucocorticoids during prolonged use. The Glucocorticoid Toxicity Index-Metabolic Domains (GTI-MD) is an abbreviated GTI version limited to the 4 metabolic domains. A GTI-MD score of 0 indicates a low likelihood of toxicity in the assessed metabolic domains.
Time frame: Up to 51 months
Prednisone dose reduction (average monthly dose) over time
Time frame: Up to 51 months
TIS over time
The total improvement score (TIS) assesses minimal, moderate, and major clinical response, and it is assessed using the ACR/EULAR criteria. The total score varies between 0 and 100, with higher scores indicating greater improvement.
Time frame: Up to 51 months
Proportion of TIS responders (minimal, moderate, major) over time
The total improvement score (TIS) assesses minimal, moderate, and major clinical response, and it is assessed using the ACR/EULAR criteria. The total score varies between 0 and 100, with higher scores indicating greater improvement
Time frame: Up to 51 months
Individual CSMs of the TIS over time
The total improvement score (TIS) assesses minimal, moderate, and major clinical response, and it is assessed using the ACR/EULAR criteria. The ACR/EULAR criteria calculate TIS using the 6 core set measure (CSMs): MDGA, PGA, MMT8, HAQ-DI, muscle enzymes, and extramuscular global assessment (assessed by the MDAAT).
Time frame: Up to 51 months
Percentage of participants with clinically inactive disease
Clinically inactive disease is defined as no evidence of disease activity, based on an Physician Global Assessment of Disease Activity (MDGA) and Extramuscular Global Assessment of the Myositis Disease Activity Assessment Tool (MDAAT) of 0 and normal creatine kinase (CK) values for at least 12 weeks (at week 28 and every 24 weeks thereafter).
Time frame: Up to 51 months
Percentage of participants with remission during the study
Remission is defined as a clinically inactive disease for at least 24 weeks
Time frame: Up to 51 months
PGI-S over time
The Patient Global Impression of Severity (PGI-S) asks participants to rate the severity of their disease symptoms over the past 7 days on a 4-point Likert scale, where scores range from "no symptoms" to "severe."
Time frame: Up to 51 months
CGI-S over time
The Clinical Global Impression of Severity (CGI-S) asks the physician to rate the severity of the participant's disease on a 4-point Likert scale, where scores range from "no activity" to "severe".
Time frame: Up to 51 months
Physical Functioning subscale and Physical Component Summary scores of the SF-36v2 over time
The 36-Item Short Form Survey version 2 (SF-36v2) is a 36-item scale constructed to survey health-related quality of life in 8 domains.
Time frame: Up to 51 months
EQ-5D-5L utilities over time
The EQ-5D-5L questionnaire is a standardized test recognized by many health authorities as a generic measure of health status for clinical and economic appraisal. The descriptive system comprises 5 dimensions, each having 5 levels ranging from "No problem" to "Extreme problem".
Time frame: Up to 51 months
EQ-5D-5L VAS over time
The EQ-5D-5L questionnaire is a standardized test recognized by many health authorities as a generic measure of health status for clinical and economic appraisal. A visual analog scale (VAS) is included in the EQ-5D-5L, where participants will mark their health status from 0 (the worst health you can imagine) to 100 (the best health you can imagine).
Time frame: Up to 51 months
Percent change from baseline in total IgG levels in serum over time
Time frame: Up to 53 months
Incidence of ADA against efgartigimod (serum levels) over time
ADA : anti-drug antibodies.
Time frame: Up to 53 months
Proportion of participants achieving sustained low disease activity while on IMP, over time
Sustained low disease activity is defined as a CGI-S score of "mild" or "no activity" and a PGI-S score of "mild" or "no symptoms" for at least 12 weeks.
Time frame: Up to 51 months
Proportion of participants with low disease activity over time, while on IMP
Low disease activity is defined as a CGI-S score of "mild" or "no activity" and a PGI-S score of "mild" or "no symptoms"
Time frame: Up to 51 months
Proportion of participants with low disease activity who continue dosing every 2 weeks at week 52 and every 24 weeks thereafter
Low disease activity is defined as a CGI-S score of "mild" or "no activity" and a PGI-S score of "mild" or "no symptoms"
Time frame: Up to 51 months
Proportion of participants who have marked worsening during the period of dosing every 2 weeks
Marked worsening is defined as a CGI-S score of "moderate" or "severe" and a PGI-S score of "moderate" or "severe"
Time frame: Up to 51 months
Duration of dosing every 2 weeks
Time frame: Up to 51 months
Plan to share: Undecided
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Studies of the drugs tested here: Efgartigimod alfa · Hyaluronidase (human recombinant)