A study testing ACT-1004-1239 compared to placebo for adults with progressive multiple sclerosis to measure nerve repair using MRI scans

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What is this study about?

This study focuses on progressive multiple sclerosis, which is a form of a long-term condition affecting the brain and spinal cord where symptoms gradually worsen over time. The study will test a medication called ACT-1004-1239, which will be compared with placebo. Multiple sclerosis occurs when the protective covering of nerve fibers, called myelin, becomes damaged, and this study is looking at whether the medication can help repair this protective covering, a process called remyelination.

The purpose of this study is to evaluate whether ACT-1004-1239 can help restore the myelin covering of nerves in people with progressive multiple sclerosis, as measured by magnetic resonance imaging, which is a type of scan that creates detailed pictures of the inside of the body. During the study, participants will receive either the study medication or placebo for up to 48 weeks. The study will measure changes in the myelin content of a specific part of the brain called the corpus callosum, which connects the two sides of the brain. Additionally, the study will look at nerve function by measuring how quickly electrical signals travel through the visual pathway using a test called visual evoked potential.

Throughout the study, participants will undergo regular assessments including brain scans, nerve function tests, and collection of cerebrospinal fluid, which is the liquid that surrounds the brain and spinal cord. The study will also monitor safety by tracking any unwanted effects, changes in vital signs such as blood pressure and heart rate, body weight, blood and urine tests, and heart function using an electrocardiogram, which records the electrical activity of the heart. The study will also assess mood and thoughts using a specific rating scale.

1 Baseline assessments and treatment start

At the beginning of the trial, baseline measurements will be taken. These measurements will serve as a reference point to compare changes throughout the trial.

A magnetic resonance imaging scan will be performed to measure the myelin water fraction in the corpus callosum. Myelin is the protective coating around nerve fibers, and this scan measures how much myelin is present in a specific part of the brain.

Visual evoked potential testing will be conducted to measure how quickly signals travel from the eyes to the brain. This test is called P100 latency measurement.

Physical examinations will include measurements of vital signs such as blood pressure, heart rate, and temperature, as well as body weight.

Blood and urine samples will be collected for laboratory tests.

An electrocardiogram will be performed to check heart rhythm and electrical activity.

The Columbia Suicide Severity Rating Scale questionnaire will be completed to assess mental health and any thoughts of self-harm.

The Expanded Disability Status Scale assessment will be performed to evaluate the level of disability related to multiple sclerosis.

Treatment will begin with either ACT-1004-1239 or a matching placebo. The placebo is an inactive substance that looks identical to the actual medication. Neither the patient nor the medical team will know which one is being received.

The medication or placebo will be provided as hard capsules to be taken orally.

If currently taking disease-modifying therapy for multiple sclerosis, this existing treatment will continue unchanged throughout the trial, provided it has been stable for at least 6 months.

2 Week 4 assessment

At week 4, a measurement of labeled body water will be taken. This measurement will be used later to analyze certain molecules in the cerebrospinal fluid.

The trial medication or placebo will continue to be taken as prescribed.

3 Week 12 assessment

At week 12, a sample of cerebrospinal fluid will be collected. Cerebrospinal fluid is the liquid that surrounds the brain and spinal cord. This sample will be analyzed for specific molecules to evaluate the treatment effect.

Physical examinations will be performed, including measurements of vital signs and body weight.

Blood and urine samples will be collected for laboratory tests.

An electrocardiogram will be performed.

The Columbia Suicide Severity Rating Scale questionnaire will be completed.

The trial medication or placebo will continue to be taken as prescribed.

4 Week 24 final assessment

At week 24, the final assessments will be performed. This is the main evaluation point of the trial.

A magnetic resonance imaging scan will be performed to measure changes in the myelin water fraction of the corpus callosum compared to baseline.

Visual evoked potential testing will be conducted to measure changes in P100 latency compared to baseline.

A sample of cerebrospinal fluid will be collected and analyzed for specific molecules.

Physical examinations will be performed, including measurements of vital signs and body weight.

Blood and urine samples will be collected for laboratory tests.

An electrocardiogram will be performed.

The Columbia Suicide Severity Rating Scale questionnaire will be completed.

The Expanded Disability Status Scale assessment will be performed.

This marks the completion of the treatment period.

5 Follow-up period

After stopping the trial medication or placebo at week 24, a follow-up period of 30 days will occur.

For those of childbearing potential, monthly pregnancy tests will continue during this follow-up period. These tests may be urine or blood tests.

Any side effects or health changes that occur during this follow-up period will be monitored and recorded.

Contraception must continue to be used throughout this 30-day follow-up period for those of childbearing potential.

Who Can Join the Study?

You must be 18 to 55 years old, either male or female
You must have a diagnosis of primary or secondary progressive multiple sclerosis, which means a type of multiple sclerosis where symptoms gradually worsen over time. This diagnosis must be confirmed by a specialist doctor who is an expert in multiple sclerosis
You must not have had a clinical relapse in the 6 months before joining the study. A clinical relapse is when your multiple sclerosis symptoms suddenly get worse or new symptoms appear
Your Expanded Disability Status Scale score must be between 2.0 and 6.0. This is a scoring system that measures how much multiple sclerosis affects your ability to move and perform daily activities, with higher numbers meaning more disability
If you are currently taking disease-modifying therapy, which are medicines that help control multiple sclerosis, you must have been on the same stable treatment for at least 6 months before joining the study. This does not apply to medicines called B-cell depleting therapies, which are a specific type of treatment that reduces certain immune system cells
If you are a woman who can become pregnant, you must agree to take a pregnancy test every month during the study and for 30 days after stopping the study treatment
If you are a woman who can become pregnant, you must agree to use a highly effective method of birth control from the time you join the study until 30 days after stopping the study treatment

Who Cannot Join the Study?

The study has not provided specific exclusion criteria in the available information
You should discuss with the study doctor whether you are eligible to participate based on your individual health condition and medical history
General factors that typically prevent participation in clinical trials, which are research studies testing new treatments, may include having other serious health conditions, taking certain medications, or being pregnant or breastfeeding
The study doctor will review your complete medical information to determine if you can safely take part in this research

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Centre for Human Drug Research	Leiden	The Netherlands

Trial status

Country	Status	Recruitment Start
The Netherlands	Recruiting	12.11.2025

Trial locations

Investigated drugs:

ACT-1004-1239

ACT-1004-1239 is an investigational medication being tested in this trial for people with progressive multiple sclerosis. The purpose of this medication is to help repair the protective coating around nerve fibers in the brain and spinal cord, which becomes damaged in multiple sclerosis. Researchers will use special brain scans to see if this medication can help restore this protective coating.

Placebo is an inactive substance that looks like the real medication but contains no active treatment. It is used in this trial to compare against the investigational medication to help determine if the real medication is actually working.

Investigated diseases:

Progressive multiple sclerosis

Progressive Multiple Sclerosis – Progressive multiple sclerosis is a form of multiple sclerosis where the disease steadily worsens over time. In this type, nerve damage continues to accumulate without clear periods of recovery or remission. The protective coating around nerve fibers, called myelin, becomes increasingly damaged, which affects the transmission of signals between the brain and the rest of the body. As the disease progresses, people experience a gradual worsening of physical and cognitive functions. Unlike other forms of multiple sclerosis, progressive multiple sclerosis does not have distinct attacks or flare-ups. The continuous nerve damage leads to increasing disability that builds up gradually over months and years.

Trial ID:

2025-522922-11-00

Protocol code:

ID-086B201

Trial Phase:

Therapeutic exploratory (Phase II)

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A study testing ACT-1004-1239 compared to placebo for adults with progressive multiple sclerosis to measure nerve repair using MRI scans

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?