A Study of Empasiprubart as Add-On Therapy to IVIg in Adult Participants With Guillain-Barré Syndrome (embridge)

A Phase 2, Randomized, Double-Blinded, Placebo-Controlled Study to Assess the Efficacy and Safety of Empasiprubart as Add-On Therapy to IVIg in Adult Participants With Guillain-Barré Syndrome

The main purpose of this study is to learn whether empasiprubart, when given in addition to intravenous immunoglobulin (IVIg), helps adults with Guillain-Barré syndrome (GBS) recover and whether it is safe. About 63 participants will be assigned by chance to receive either empasiprubart or placebo by intravenous infusion; all participants will also receive IVIg. The study includes screening for up to 72 hours, study treatment through Day 12, and follow-up through Week 67 (15 months after the last dose of study treatment). Participation lasts up to 67 weeks.

Study Overview

• Status: Not yet recruiting
• Conditions: Guillain-Barré Syndrome (GBS)
• Intervention / Treatment: Biological: Empasiprubart IV; Biological: Intravenous immunoglobulin (IVIg); Other: Empasiprubart Placebo IV

• Study Type: Interventional
• Enrollment (Estimated): 63
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Sabine Coppieters, MD; Phone Number: 857-350-4834; Email: ClinicalTrials@argenx.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• At least 18 years old
• Clinically diagnosed with Guillain-Barré syndrome (GBS) according to NINDS (National Institute of Neurological Disorders and Stroke) diagnostic criteria
• GBS-related weakness beginning within 7 days before the first study treatment
• GBS Disability Scale (GBS-DS) score of 3, 4, or 5 at screening and baseline
• Was able to walk approximately 10 m or more without assistance before the onset of GBS symptoms
• Agrees to receive antibiotic prophylaxis against N. meningitidis and S. pneumoniae for the first 90 days of the study or until a completed vaccination schedule against these bacterial pathogens per local guidelines has been shown.

Exclusion Criteria:

• History of a previous GBS episode or diagnosis of an atypical GBS variant
• Clinical diagnosis of systemic lupus erythematosus (SLE) or known complement deficiency
• Autoimmune or neuromuscular diseases or medical conditions (eg, clinically significant renal, hepatic, cardiac, pulmonary, hematologic, or neurological conditions or clinically significant laboratory abnormalities) that would interfere with an accurate assessment of clinical symptoms of GBS, confound the study results, or put the participant at undue risk
• IVIg therapy contraindications or another medical condition that, in the opinion of the investigator, would make IVIg administration unsafe
• Recent treatment with IVIg or plasma exchange (PLEX), or recent use of certain immune-modulating or immunosuppressive therapies

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Empasiprubart + IVIg; Participants receive empasiprubart by intravenous infusion and IVIg by intravenous infusion.	Biological: Empasiprubart IV; Intravenous infusion of Empasiprubart; Biological: Intravenous immunoglobulin (IVIg); Intravenous infusion of IVIg
Placebo Comparator: Placebo + IVIg; Participants receive placebo by intravenous and IVIg by intravenous infusion.	Biological: Intravenous immunoglobulin (IVIg); Intravenous infusion of IVIg; Other: Empasiprubart Placebo IV; Intravenous infusion of Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Participants With a Guillain-Barré Syndrome Disability Scale (GBS-DS) Score ≤2 at Week 4	The Guillain-Barré Syndrome Disability Scale (GBS-DS) is a clinician-reported measure of global functional disability. It has 7 categories ranging from 0 (healthy) to 6 (death), with higher scores indicating greater disability. A GBS-DS score ≤2 indicates the participant is able to walk 10 meters or more without assistance.	at week 4

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of calendar days in the intensive care unit (ICU) within the first 4 weeks of investigational medicinal product (IMP) administration	ICU means intensive care unit; IMP means investigational medicinal product	Up to 4 weeks
Number of calendar days receiving invasive mechanical ventilation within the first 4 weeks of investigational medicinal product (IMP) administration	IMP means investigational medicinal product	Up to 4 weeks
Time From First Investigational Medicinal Product (IMP) Administration to Achieving a Guillain-Barré Syndrome Disability Scale (GBS-DS) Score ≤2	IMP means investigational medicinal product; The Guillain-Barré Syndrome Disability Scale (GBS-DS) is a clinician-reported measure of global functional disability with 7 categories ranging from 0 (healthy) to 6 (death), with higher scores indicating greater disability.	Up to 52 weeks
Actual values in the Inflammatory Rasch-Built Overall Disability Scale (I-RODS) Scores at weeks 13 and 26	The Inflammatory Rasch-Built Overall Disability Scale (I-RODS) is a 24-item participant-reported measure of disability that assesses limitations in activities and social participation. Raw scores range from 0 to 48 and are converted to a centile metric score ranging from 0 (most severe activity and social participation limitations) to 100 (no activity and social participation limitations). Higher scores indicate less disability.	Up to 26 weeks
Actual values in the Overall Neuropathy Limitations Scale (ONLS) Score at weeks 13 and 26	The Overall Neuropathy Limitations Scale (ONLS) is a clinician-reported measure of functional limitations in the upper and lower limbs. The upper-limb section is scored from 0 to 5 and the lower-limb section from 0 to 7. A score of 0 indicates no limitations, while scores of 5 (upper limbs) or 7 (lower limbs) indicate no purposeful movement. Higher scores therefore indicate greater functional limitation.	Up to 26 weeks
Change from baseline in the Medical Research Council Sum Score (MRC-SS) over time	The Rasch-built Medical Research Council Sum Score (MRC-SS) is a clinician-assessed measure of muscle strength in selected upper and lower extremity muscle groups bilaterally. The resulting score is used to evaluate the severity of weakness and changes in motor function over time, with higher scores reflecting greater muscle strength.	Up to 52 weeks
Change from baseline in the Medical Research Council Sum Score (MRC-SS) neck flexion assessment over time	The Rasch-built Medical Research Council Sum Score (MRC-SS) neck flexion assessment evaluates the strength of the neck flexion muscles. The participant is asked to flex the neck (bring the chin toward the chest) while the examiner evaluates muscle strength using a Rasch-modified MRC grading system that ranges from 0 (no visible contraction) to 3 (normal strength).	Up to 52 weeks
Change from baseline in the Guillain-Barré Syndrome Disability Scale (GBS-DS) score over time	The Guillain-Barré Syndrome Disability Scale (GBS-DS) is a clinician-reported measure of global functional disability. It has 7 categories ranging from 0 (healthy) to 6 (death), with higher scores indicating greater disability.	Up to 52 weeks
Actual Inflammatory Rasch-Built Overall Disability Scale (I-RODS) Scores Over Time	The Inflammatory Rasch-Built Overall Disability Scale (I-RODS) is a 24-item participant-reported measure of disability that assesses limitations in activities and social participation. Raw scores range from 0 to 48 and are converted to a centile metric score ranging from 0 (most severe activity and social participation limitations) to 100 (no activity and social participation limitations). Higher scores indicate less disability.	Up to 52 weeks
Actual Overall Neuropathy Limitations Scale (ONLS) Score Over Time	The Overall Neuropathy Limitations Scale (ONLS) is a clinician-reported measure of functional limitations in the upper and lower limbs. The upper-limb section is scored from 0 to 5 and the lower-limb section from 0 to 7. A score of 0 indicates no limitations, while scores of 5 (upper limbs) or 7 (lower limbs) indicate no purposeful movement. Higher scores therefore indicate greater functional limitation.	Up to 52 weeks
Number of calendar days receiving invasive mechanical ventilation through week 52		Up to 52 weeks
Proportion of participants who require invasive mechanical ventilation over time and at any time through the week 52		Up to 52 weeks
Number of calendar days in the Intensive Care Unit (ICU) through week 52	ICU means intensive care unit.	Up to 52 weeks
Proportion of participants in the Intensive Care Unit (ICU) over time and at any time through week 52	ICU means intensive care unit.	Up to 52 weeks
Number of calendar days from the start of investigational medicinal product (IMP) until discharge from the acute care facility/department	IMP means investigational medicinal product	Up to 52 weeks
Number of calendar days from the start of investigational medicinal product (IMP) until discharge from the last rehabilitation unit	IMP means investigational medicinal product	Up to 52 weeks
All-cause mortality through week 52		Up to 52 weeks
Incidence of Adverse events (AEs) and Adverse Events of Special Interest (AESIs)	AE = adverse event; AESI = adverse event of special interest	Up to 67 weeks
Incidence of Serious Adverse Events (SAEs)	SAE = Serious adverse event.	Up to 67 weeks
Serum concentrations of empasiprubart over time		Up to 52 weeks
Percentage Change From Baseline in Free Complement Component 2 (C2) Over Time	C2 = complement component 2	Up to 52 weeks
Percentage Change From Baseline in Total Complement Component 2 (C2) Over Time	C2 = complement component 2	Up to 52 weeks

Collaborators and Investigators

• Sponsor: argenx

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): March 1, 2029

Study Registration Dates

• First Submitted: September 10, 2026
• First Submitted That Met QC Criteria: September 10, 2026
• First Posted (Actual): September 16, 2026

Study Record Updates

• Last Update Posted (Actual): September 16, 2026
• Last Update Submitted That Met QC Criteria: September 10, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Post-Infectious Disorders; Nervous System Diseases; Pathologic Processes; Neuromuscular Diseases; Chronic Disease; Disease Attributes; Autoimmune Diseases; Immune System Diseases; Peripheral Nervous System Diseases; Autoimmune Diseases of the Nervous System; Demyelinating Diseases; Polyneuropathies; Polyradiculoneuropathy; Pathological Conditions, Signs and Symptoms; Guillain-Barre Syndrome; Amino Acids, Peptides, and Proteins; Proteins; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Serum Globulins; Globulins; Immunoglobulin Isotypes; Immunoglobulin G; Immunoglobulins, Intravenous
• Other Study ID Numbers: ARGX-117-29-GBS-2001; 2026-527247-17-00 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No