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A study to test if empasiprubart can improve function and is safe for adults with chronic inflammatory demyelinating polyneuropathy

Fast replyInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at Chronic Inflammatory Demyelinating Polyneuropathy, which is a condition that affects the nerves outside the brain and spinal cord. In this condition, the protective covering of the nerves becomes damaged, leading to weakness, numbness, and difficulties with movement and daily activities. The study will test a medication called empasiprubart, which is also known by its code name ARGX-117. This medication works by targeting a specific part of the immune system that may be involved in causing nerve damage. Some people in the study will receive empasiprubart while others will receive placebo.

The purpose of the study is to see if empasiprubart can help improve the ability to perform daily activities compared to placebo. The study will also look at how safe the medication is and how well it is tolerated by people with this nerve condition. Researchers want to understand if this treatment can help reduce disability and improve quality of life for people living with this condition.

The study is divided into two parts and will last up to about two years for each person who takes part. During the study, empasiprubart will be given through a needle into a vein, which is called an infusion. People taking part will have regular visits where doctors will check their muscle strength, ability to perform daily tasks, grip strength, and overall well-being. The study will also measure various safety aspects including blood tests, heart function tests, and any side effects that may occur. Throughout the study, researchers will collect blood samples to measure the levels of the medication in the body and to see how the immune system responds to the treatment.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment assignment

    Upon joining the study, you will be randomly assigned to receive either empasiprubart or placebo. Empasiprubart is the medication being tested, while placebo is an inactive substance that looks like the medication but contains no active ingredient.

    Neither you nor your doctor will know which treatment you are receiving during the study. This is called a double-blinded study design.

  2. Step 2

    Treatment administration

    You will receive your assigned treatment through an intravenous infusion, which means the medication will be delivered directly into your vein through a needle.

    The study medication is called ARGX-117 and comes as a concentrate that will be prepared as a solution for infusion.

  3. Step 3

    Part A - Initial treatment period

    The first part of the study lasts 24 weeks.

    During this period, your functional ability will be assessed using the aINCAT score, which measures your ability to perform daily activities with your arms and legs.

    Your muscle strength will be evaluated using the MRC-SS, which stands for Medical Research Council Sum Score.

    Your grip strength will be measured in your dominant hand and both hands using daily measurements.

    The I-RODS score will assess your ability to perform activities of daily living. This stands for Inflammatory Rasch-built Overall Disability Scale.

    The TUG test will measure the time it takes you to stand up, walk, turn around, and sit back down. This stands for Timed Up and Go test.

    Your quality of life will be evaluated using the EQ-5D-5L questionnaire, which assesses mobility, self-care, usual activities, pain, and anxiety.

    Fatigue will be measured using the RT-FSS, which is the Rasch-built fatigue severity scale.

    Any pain you experience will be assessed with the BPI-SF, which stands for Brief Pain Inventory - Short Form.

    You will rate your overall condition using PGI-S (Patient Global Impression of Severity) and changes in your condition using PGI-C (Patient Global Impression of Change).

  4. Step 4

    Part B - Extended treatment period

    After completing the first 24 weeks, you may continue in the study for an extended period.

    Part B can last up to 96 weeks in total.

    During this extended period, the same assessments will continue to be performed to monitor your muscle strength, functional ability, and overall well-being over time.

  5. Step 5

    Safety monitoring

    Throughout the study, you will be monitored for any adverse events, which are any unwanted medical occurrences or side effects.

    Blood samples will be taken to check for ADA (anti-drug antibodies) and NAb (neutralizing antibodies), which are substances your body might produce in response to the study medication.

    Laboratory tests will be performed regularly to monitor your blood values and overall health.

    Your heart function will be checked using ECG (electrocardiogram), which records the electrical activity of your heart.

    Your vital signs will be measured, including blood pressure, heart rate, and temperature.

    Blood levels of C2, which is a component of your immune system called complement, will be measured to see how the medication affects it.

    The concentration of empasiprubart in your blood will be measured at various times during the study.

Who can join the trial?

6 criteria

  • You must meet the criteria for CIDP, which is a condition where the protective covering of nerves becomes damaged and causes weakness and numbness, based on specific medical guidelines from 2021
  • You must have either typical CIDP or one of these specific forms: motor CIDP (affecting mainly movement, including cases where movement problems are the main issue), multifocal CIDP (also called Lewis-Sumner syndrome, where several separate areas are affected), focal CIDP (affecting one specific area), or distal CIDP (affecting the parts of the body furthest from the center, like hands and feet)
  • You must have remaining disability and your disease must still be active, meaning you continue to experience symptoms
  • You must be in one of these treatment situations: you have never received treatment for CIDP before, or you have stopped receiving CIDP treatment, or you are currently receiving CIDP treatment which may include steroid medications given in pulses or taken by mouth, immunoglobulins (proteins that help fight disease), PLEX (a procedure that filters your blood), or FcRn inhibitors (medications that block a specific protein in the body)
  • You can be male or female
  • You must be an adult

Who cannot join the trial?

3 criteria

  • The study does not list specific reasons why patients cannot participate in the trial at this time
  • If you are considering joining this study, the research team will review your medical history and current health condition to determine if you are eligible
  • General factors that might prevent participation will be assessed during the screening process, which is when doctors check if you meet all requirements to join the study
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Investigated drugs

  • Empasiprubart IV

    is an investigational medication given through a vein (intravenous or IV). In this study, it is being tested to see if it can help improve how well the body functions in adults with a condition called chronic inflammatory demyelinating polyneuropathy, which affects the nerves. The medication works by targeting certain processes in the immune system that may be causing nerve damage.

  • Placebo

    is an inactive substance that looks like the real medication but contains no active treatment. It is used in this study to compare against empasiprubart IV to determine if the actual medication is effective. Some participants will receive the placebo instead of the active medication.

What is already known about the treatment

Empasiprubart – Empasiprubart is an investigational medication administered intravenously (through a vein) that is currently being studied in clinical trials for the treatment of chronic inflammatory demyelinating polyneuropathy, a condition where the immune system attacks the protective covering of nerves. The drug works by targeting and blocking specific immune system proteins that cause inflammation and damage to the nerve's protective layer, helping to reduce the body's harmful immune response. It belongs to a class of medications called immunomodulators, which are designed to modify or regulate the immune system's activity to prevent it from attacking the body's own tissues.

Investigated diseases

Chronic Inflammatory Demyelinating Polyneuropathy – Chronic inflammatory demyelinating polyneuropathy is a neurological disorder that affects the peripheral nerves throughout the body. The condition occurs when the immune system mistakenly attacks the protective covering of nerves called myelin, leading to nerve damage. This damage causes progressive weakness and loss of sensation, typically affecting both sides of the body. Patients often experience difficulty with movement and coordination, particularly in their arms and legs. The disease develops slowly over time, with symptoms gradually worsening over a period of at least eight weeks. Common manifestations include reduced grip strength, impaired ability to perform daily activities, and challenges with balance and walking.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-520805-10-00Protocol codeARGX-117-2402Estimated enrolment186 patientsSponsorArgenx

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

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