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EFG PH20

Phase 2

Active Idiopathic Inflammatory Myopathy | Monoclonal antibody | Rare Disease |argenx SE|Last Updated: Jul 24, 2026

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

Clinical trial landscape

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 used for?

EFG PH20 is an investigational monoclonal antibody being studied for the treatment of active idiopathic inflammatory myopathy, a group of rare muscle diseases that includes myositis, dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and antisynthetase syndrome. It is administered subcutaneously and is currently in clinical development.

Who makes EFG PH20?

EFG PH20 is being developed by argenx SE, a biopharmaceutical company traded on the NASDAQ under the ticker ARGX. The company is conducting clinical trials to evaluate the efficacy and safety of this investigational therapy in patients with active idiopathic inflammatory myopathy.

What phase is EFG PH20 in?

EFG PH20 is in Phase 2 clinical development. It is an investigational drug, meaning it has not been approved by regulatory authorities and is still being studied for safety and efficacy in patients with active idiopathic inflammatory myopathy.

What clinical trials is EFG PH20 in?

EFG PH20 has one completed Phase 2 clinical trial, registered as NCT05523167. This randomized, double-blind, placebo-controlled study enrolled 265 adult participants with active idiopathic inflammatory myopathy and evaluated the efficacy and safety of the drug across multiple countries worldwide.

How does EFG PH20 work?

EFG PH20 is a monoclonal antibody designed to target and neutralize the activity of the neonatal Fc receptor, which plays a role in recycling immunoglobulin G antibodies. By blocking this receptor, the drug reduces levels of pathogenic IgG antibodies that contribute to the muscle inflammation seen in idiopathic inflammatory myopathy.

Is EFG PH20 the same as efgartigimod PH20 SC?

Yes, EFG PH20 is the same drug as efgartigimod PH20 SC. The clinical trial NCT05523167, which investigated the efficacy and safety of efgartigimod PH20 SC in adults with active idiopathic inflammatory myopathy, is the trial associated with EFG PH20.