A Study to Assess the Long-term Safety and Efficacy of a Subcutaneous Formulation of Efgartigimod in Adults With Chronic Inflammatory Demyelinating Polyneuropathy (CIDP, an Autoimmune Disorder That Affects the Peripheral Nerves)

Phase 2

Active, not recruiting

• Conditions: Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
• Interventions: Biological: Efgartigimod PH20 SC

• Registration Number: NCT04280718
• Lead Sponsor: argenx

Brief Summary

This is the open-label extension study of phase II ARGX-113-1802 to evaluate the long-term safety and efficacy of the subcutaneous formulation of efgartigimod in adults with CIDP.

Patients already stabilized on efgartigimod PH20 SC will also have the opportunity to participate in a sub study to explore less frequent dosing of efgartigimod PH20 SC.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2020-02-20
• Study First Submitted QC: 2020-02-20
• Study First Posted: 2020-02-21
• Study Start: 2020-09-18
• Status Verified: 2025-06
• Last Update Submitted: 2025-06-25
• Last Update Posted: 2025-06-29
• Primary Completion: 2027-04-30
• Study Completion: 2027-04-30

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 229

Inclusion Criteria

1. Ability to understand the requirements of the trial, provide written informed consent (including consent for the use and disclosure of research-related health information), willingness and ability to comply with the trial protocol procedures (including required trial visits) of this trial.

2. Male or female patient with one of the following options:

   • Have completed the Week-48 visit of Stage B of the ARGX-113-1802 trial and are considered to be eligible for treatment with efgartigimod PH20 SC; or
   • Have deteriorated during Stage B of the ARGX-113-1802 trial and are considered to be eligible for treatment with efgartigimod PH20 SC, or
   • Have been offered the participation in the OLE trial due to early termination of the ARGX-113-1802 trial (because sufficient events for the primary endpoint analysis of the that trial have been reached and it is stopped) and are considered to be eligible for treatment with efgartigimod PH20 SC treatment; or
   • Have completed the Week-48 visit of the previous cycle of the OLE trial and are considered to be eligible to continue with efgartigimod PH20 SC treatment.

3. Women of childbearing potential who have a negative urine pregnancy test at baseline before IMP administration.

4. Women of childbearing potential must use an acceptable method of contraception from signing the ICF until the date of the last administration of IMP.

Exclusion Criteria

1. Week-48/ED visit in the ARGX-113-1802 trial or the Week-48 visit of the previous OLE participation occurred more than 14 days prior to SD1 of the OLE trial or the start of a new treatment cycle in the OLE trial and more than 21 days since the last dose of IMP.
2. Pregnant and lactating women and those intending to become pregnant during the trial.
3. Patients with clinical evidence of other significant serious disease or patients who underwent a recent or have a planned major surgery, or patients who (intend to) use prohibited medications (see protocol) and therapies during the trial, or any other reason which could confound the results of the trial or put the patient at undue risk.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
efgartigimod PH20 SC	Efgartigimod PH20 SC	Patients treated with efgartigimod PH20 SC

Primary Outcome Measures

Name	Time	Method
Incidence of treatment-emergent adverse events and serious adverse events	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study

Secondary Outcome Measures

Name	Time	Method
Change from baseline over time of the adjusted INCAT score	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Adjusted Inflammatory Neuropathy Cause and Treatment Disability Score (aINCAT) score is a 10-point scale that covers the functionality of legs and arms. The score varies between 0 and 10 (higher score, worse outcome).
Change from baseline over time of the MRC Sum score	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Medical Research Council Sum Score evaluates motor strength. Evaluated on 6 muscle groups on each side, the score varies from 0 to 60 (lower score, worse outcome).
Change from baseline over time of I-RODS disability scores	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	Inflammatory Rasch-built Overall Disability Scale (I-RODS) assesses the limitations of activities and social participation in patients with inflammatory neuropathies like CIDP. The score ranges from 0 to 100 (higher score, worse outcome).
Change from baseline over time of mean grip strength	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study
Change from baseline over time of TUG score	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Timed Up and Go Test (TUG) is a simple test to assess a person's mobility in which the time expended to rise from a chair, walk 3 meters, turn around, walk back to the chair, and sit down is measured.
Percentage of patients without clinical deterioration over time, defined by adjusted INCAT deterioration ≥1 point compared to baseline.	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Adjusted Inflammatory Neuropathy Cause and Treatment Disability Score (aINCAT) score is a 10-point scale that covers the functionality of legs and arms. The score varies between 0 and 10 (higher score, worse outcome).
Percentage of patients with titers of binding antibodies towards efgartigimod and the presence of neutralizing antibodies against efgartigimod.	Up to 51 weeks
Efgartigimod serum concentrations	Up to 51 weeks
Changes from baseline over time of serum IgG levels (total)	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study
Change from baseline over time in EQ-5D-5L	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	EQ-5D-5L questionnaire is a patient-reported outcome measure, ranging 0 to 100 (lower score, worse outcome).
Change from baseline over time in BPI SF	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Brief Pain Inventory-Short Form (BPI-SF) is a patient-reported outcome measure to assess pain severity and pain interference
Change from baseline over time in TSQM-9	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Treatment Satisfaction Questionnaire for Medication (TSQM) is a 9-item questionnaire to assess treatment satisfaction in naturalistic study designs, in which there is potential that the administration of the side effects domain of the TSQM would interfere with routine clinical care
Change from baseline over time in RT-FSS	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Rasch-Transformed Fatigue Severity Scale (RT-FSS) is a 7-item self-reported questionnaire designed to differentiate fatigue from clinical depression. The participant has to rate from 0 to 3 their level of fatigue on 7 items (low score indicates that the statement is not very appropriate, and high score indicates agreement).
Change from baseline over time in HADS	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study	The Hospital Anxiety and Depression Scale (HADS) aims to measure symptoms of anxiety and depression in people with physical health problems. HADS is a 14-item scale with 7 items related to anxiety and 7 to depression
Percentage of patients performing self-administration over time	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study
Percentage of patients with treatment administered by caregiver over time.	Up to 48 weeks per cycle (each cycle is 48 weeks) until the end of the study

Trial Locations

Locations (147)

Investigator site 0010065; 🇺🇸 Birmingham, Alabama, United States

Investigator site 0010013; 🇺🇸 Phoenix, Arizona, United States

Investigator site 0010055; 🇺🇸 Scottsdale, Arizona, United States

Investigator site 0010032; 🇺🇸 Carlsbad, California, United States

Investigator site 10190; 🇺🇸 Pomona, California, United States

Investigator site 0010160; 🇺🇸 Rancho Mirage, California, United States

Investigator site 0010071; 🇺🇸 San Francisco, California, United States

Investigator site 0010057; 🇺🇸 Centennial, Colorado, United States

Investigator site 0010072; 🇺🇸 Boca Raton, Florida, United States

Investigator site 0010144; 🇺🇸 Coral Springs, Florida, United States

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