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EFG PH20

Phase 2

Active Idiopathic Inflammatory Myopathy | Monoclonal antibody | Rare Disease |argenx SE|Trials Updated: Sep 21, 2026

EFG PH20 target and mechanism

ModalityMonoclonal antibody

Also known as EFG PH20 SC

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment265

FDA Designations

No designations recorded

EFG PH20 clinical trials

EFG PH20 · 1 trial · 6 indications

Phase 2 1
NCT05523167A Study to Investigate the Efficacy and Safety of Efgartigimod PH20 SC in Adult Participants With Active Idiopathic Inflammatory Myopathy.Active Idiopathic Inflammatory Myopathy
COMPLETED265 Analytics
PHASE2COMPLETED
A Study to Investigate the Efficacy and Safety of Efgartigimod PH20 SC in Adult Participants With Active Idiopathic Inflammatory Myopathy.
Active Idiopathic Inflammatory MyopathyUnlock trial analytics

Study Endpoints

Primary Endpoints

Mean TIS
phase 2: 24 weeks; phase 3: 52 weeks

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).

Secondary Endpoints

Time to reach TIS ≥ 20 (first "minimal clinical improvement")
phase 2: up to 24 weeks; phase 3: up to 52 weeks
Percentage of participants with TIS ≥ 20
phase 2: up to 24 weeks; phase 3: up to 52 weeks
Time to reach TIS ≥ 40 (first "moderate clinical improvement")
phase 2: up to 24 weeks; phase 3: up to 52 weeks
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
EFG PH20 SCEXPERIMENTALparticipants receiving efgartigimod PH20 SC on top of background treatment
PBO PH20 SCPLACEBO_COMPARATORparticipants receiving placebo PH20 SC on top of background treatment

Interventions

NameTypeDescription
EFG PH20 SCBIOLOGICALSubcutaneous injection of efgartigimod coformulated with rHuPH20, a permeation enhancer
PBOOTHERSubcutaneous injection of placebo coformulated with rHuPH20, a permeation enhancer
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites202

Inclusion Criteria: * Ability to consent in the jurisdiction in which the study is taking place and capable of giving signed informed consent. * A definite or probable clinical diagnosis of idiopathic inflammatory myopathy (IIM) * One of the following medical histories: Diagnosis of dermatomyositis...

Countries:United StatesArgentinaAustraliaAustriaBelgiumBulgariaCanadaChinaCyprusCzechiaDenmarkFranceGeorgiaGermanyGreeceHungaryIrelandIsraelItalyJapanLithuaniaMexicoNetherlandsPeruPolandPortugalSerbiaSlovakiaSouth KoreaSpainSwedenSwitzerlandTaiwanThailandTurkey (Türkiye)United Kingdom
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Recent Changes (Last 90 Days)

MEDIUMAug 24, 2026NCT05523167TRIAL_REMOVED: changed
MEDIUMAug 24, 2026NCT05523167TRIAL_REMOVED: changed
MEDIUMAug 24, 2026NCT05523167TRIAL_REMOVED: changed
HIGHJul 24, 2026NCT05523167Status: ACTIVE_NOT_RECRUITING → COMPLETED
HIGHJul 24, 2026NCT05523167Status: ACTIVE_NOT_RECRUITING → COMPLETED

Frequently asked questions about EFG PH20

What is EFG PH20?

EFG PH20 is an investigational monoclonal antibody developed by argenx SE for active idiopathic inflammatory myopathy, a group of rare autoimmune muscle disorders. It is also known as EFG PH20 SC, where SC refers to subcutaneous administration. It has been studied in a Phase 2 clinical trial and is not yet approved.

What is EFG PH20 used for?

EFG PH20 is being developed to treat active idiopathic inflammatory myopathy, which includes myositis, dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and antisynthetase syndrome. The Phase 2 study enrolled adults 18 years and older with these active muscle conditions. It remains investigational and is not approved for any use.

Who makes EFG PH20?

EFG PH20 is developed by argenx SE, a biotechnology company whose shares trade under the ticker ARGX. Argenx sponsored the Phase 2 clinical trial evaluating the drug in active idiopathic inflammatory myopathy. The asset is also referred to as EFG PH20 SC.

What phase is EFG PH20 in?

EFG PH20 is in Phase 2 development. Its single clinical trial, NCT05523167, has been completed, and no trials are currently active. The drug is investigational and has not been approved by the FDA or any other regulatory agency for active idiopathic inflammatory myopathy or any other indication.

What clinical trials is EFG PH20 in?

EFG PH20 has been studied in one clinical trial, NCT05523167, titled A Study to Investigate the Efficacy and Safety of Efgartigimod PH20 SC in Adult Participants With Active Idiopathic Inflammatory Myopathy. The Phase 2 trial was randomized, double-blind, and placebo-controlled, enrolling 265 participants across 37 countries. It is now completed.

Is EFG PH20 the same as EFG PH20 SC?

Yes, EFG PH20 SC is an alternative name for EFG PH20. The SC designation refers to the subcutaneous formulation of the monoclonal antibody. Both names refer to the same investigational asset developed by argenx SE for active idiopathic inflammatory myopathy, studied in the completed Phase 2 trial NCT05523167.