A Phase 2/3 interventional study of EFG PH20 SC and PBO in Active Idiopathic Inflammatory Myopathy, Myositis and Dermatomyositis, sponsored by argenx. Completed at 202 sites in 36 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by argenx · Phase 2/3, Interventional, and Treatment
This study's purpose is to measure the treatment response from efgartigimod PH20 SC compared with placebo in participants with Idiopathic Inflammatory Myopathy (IIM). Participants with the IIM subtypes of dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), or certain other subtypes of polymyositis (PM; including antisynthetase syndrome [ASyS]) will be included in the study. Treatment response will be measured by Total improvement score (TIS).
184 studies on the registry are indexed under Dermatomyositis; 63 are open to participants now.
This study's enrollment of 265 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.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
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.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
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.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
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.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
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.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
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.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
participants receiving efgartigimod PH20 SC on top of background treatment
Biological: EFG PH20 SC
participants receiving placebo PH20 SC on top of background treatment
Other: PBO
Subcutaneous injection of efgartigimod coformulated with rHuPH20, a permeation enhancer
Subcutaneous injection of placebo coformulated with rHuPH20, a permeation enhancer
Mean TIS
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: phase 2: 24 weeks; phase 3: 52 weeks
Time to reach TIS ≥ 20 (first "minimal clinical improvement")
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Percentage of participants with TIS ≥ 20
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Time to reach TIS ≥ 40 (first "moderate clinical improvement")
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Percentage of participants with TIS ≥ 40
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Change in MMT8 score
The manual muscle testing-8 (MMT8) is a physician assessment of muscle strength in a set of 8 designated muscles tested bilaterally and axially. The highest total potential MMT8 score is 150
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Change in Patient Global Assessment of Disease Activity (PGA)
The Patient Global Assessment of Disease Activity (PGA) is a tool that measures a patient's global evaluation of their overall disease activity at the time of assessment using a 10-cm VAS. The participant rates their overall disease activity by drawing a vertical mark on a 10-cm VAS from the left end of the line (no evidence of disease activity) to the right end of the line (extremely active or severe disease activity).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Change in Physician Global Assessment of Disease Activity (MDGA)
The Physician Global Assessment of Disease Activity (MDGA) is a tool that measures the physician's global evaluation of the participant's overall disease activity, defined as potentially reversible pathology or physiology resulting from IIM. The physician rates disease activity on the MDGA using a 10-cm VAS. Overall disease activity is rated by drawing a vertical mark on a 10-cm VAS from the left end of the line (no evidence of disease activity), midpoint of the line (moderate disease activity), and the right end of the line (extremely active or severe disease activity).
Time frame: phase 2: up to 24 weeks; phase 3: up to 52 weeks
Proportion of participants who have at least moderate improvement (≥40) in TIS at week 52 and adhere to an oral prednisone dosage of ≤5 mg/day (or equivalent) from week 44 onward
The Total improvement score (TIS) assesses minimal, moderate, and major clinical response, and is assessed using the ACR/EULAR criteria. It is measured on a 0 to 100 scale. Higher scores represent improvement; zero indicates no improvement or worsening (from baseline).
Time frame: Phase 3: up to 52 weeks
Change in CK abnormality grades at week 52
CK: creatine kinase
Time frame: Phase 3: up to 52 weeks
Change in CDASI activity score at week 52
The Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) is a skin-specific outcome measure used to assess disease in patients with Dermatomyositis (DM). Disease in 15 different anatomical locations is rated using 3 activity measures (erythema, scale, erosion/ulceration) and 2 damage measures (poikiloderma, calcinosis). The resulting activity and damage scores range from 0 to 100 and 0 to 32, respectively. Higher scores indicate greater disease severity.
Time frame: Phase 3: up to 52 weeks
Showing the first 100 of 202 sites across 36 countries. Choose a country and city above to see the rest.
This study is completed, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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