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Study on ATX-01 for Adults Aged 18-64 with Myotonic Dystrophy Type 1 (DM1)

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What is this trial about?

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

This clinical trial is focused on studying a condition known as Myotonic Dystrophy Type 1 (DM1), which is a genetic disorder that affects muscle function. The study will evaluate a new treatment called ATX-01, which is a solution for injection or infusion. This treatment involves a novel synthetic antisense oligonucleotide, which is a type of genetic material designed to target specific molecules in the body. The purpose of the study is to assess the safety and tolerability of ATX-01 in adults with DM1.

Participants in the study will receive either the ATX-01 treatment or a placebo. The study will be conducted in a double-blind manner, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. The study will involve both single and multiple doses of the treatment, administered intravenously, which means it will be given directly into a vein. The trial will include regular monitoring to ensure the safety of participants and to observe any effects of the treatment.

The study aims to gather information on how the body processes ATX-01 and its potential effects on the symptoms of Myotonic Dystrophy Type 1. Participants will be monitored for any side effects, and various health parameters will be assessed throughout the study. The trial is expected to provide valuable insights into the potential benefits and risks of ATX-01 for individuals with DM1.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying age, diagnosis of myotonic dystrophy type 1 (DM1), and ability to walk a 10-meter distance without assistive devices, except for ankle-foot orthoses.

    Additional criteria include a body mass index (BMI) of less than 35 kg/m² and the ability to provide informed consent.

  2. Step 2

    Baseline measurements

    Baseline measurements are taken to establish initial health status. These include clinical safety laboratory tests, electrocardiogram (ECG) parameters, and urine kidney biomarkers.

    Vital signs and any existing symptoms are recorded. Muscle biopsies may be performed as part of the baseline assessment.

  3. Step 3

    Treatment administration

    Participants receive the study medication, ATX-01, or a placebo through intravenous administration. The medication is a solution for injection or infusion.

    The study involves both single and multiple ascending doses to evaluate safety and tolerability.

  4. Step 4

    Monitoring and follow-up

    Participants are monitored for any adverse events, including serious adverse events and those of special interest. Monitoring includes regular check-ups and assessments.

    Changes from baseline in clinical safety laboratory tests, ECG parameters, and vital signs are evaluated. Suicidal ideation and behavior are assessed using the Columbia-Suicide Severity Rating Scale (C-SSRS).

  5. Step 5

    Pharmacokinetic and pharmacodynamic assessments

    Pharmacokinetic (PK) parameters of ATX-01 are measured in plasma and urine to understand how the drug is processed in the body.

    Pharmacodynamic (PD) biomarkers are assessed, including changes in muscle protein expression and RNA splice index.

  6. Step 6

    Efficacy evaluation

    The study evaluates preliminary clinical efficacy by measuring changes in hand opening time, ankle dorsiflexion strength, and the impact of myotonia on daily activities.

    Participants' mobility, upper extremity function, breathing, stamina, and gastrointestinal symptoms are assessed through questionnaires.

  7. Step 7

    Study completion

    The study is estimated to conclude by December 15, 2025. Participants are expected to refrain from sharing personal medical data or study information publicly until the study is completed.

Who can join the trial?

9 criteria

  • The participant must be between 18 and 64 years old when signing the consent form.
  • The participant must have a confirmed diagnosis of **Myotonic Dystrophy Type 1 (DM1)**. This is supported by a specific genetic test showing more than 150 repeats in a gene called **DMPK**.
  • The participant must be able to walk or run 10 meters without using devices like canes or walkers, except for special braces for the ankle and foot.
  • The participant must have **grip myotonia**, which means their hand muscles take longer to relax after squeezing, lasting more than 3 seconds.
  • The participant's **Body Mass Index (BMI)** must be less than 35. BMI is a measure of body fat based on height and weight.
  • Both male and female participants are eligible.
  • The participant must be able to understand and sign a consent form, agreeing to follow the study's rules and restrictions.
  • The participant must agree not to share any personal medical information or details about the study on social media or public platforms until the study is finished.
  • The participant must be able to undergo **muscle biopsies**, which are small samples taken from muscles for testing, as required by the study schedule.

Who cannot join the trial?

4 criteria

  • Individuals who do not have Myotonic dystrophy type 1 (DM1) cannot participate. DM1 is a genetic disorder that affects muscle function.
  • Participants must be adults, meaning they are 18 years or older.
  • Both males and females are eligible, but certain health conditions or treatments may exclude them.
  • People who are considered part of a vulnerable population may be excluded. This term refers to groups who might be at higher risk of harm or exploitation, such as those with limited decision-making ability.
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Investigated drugs

ATX-01 is an experimental medication being tested for its safety and tolerability in adults with Classic Myotonic Dystrophy Type 1 (DM1). This study involves giving the medication through an intravenous (IV) infusion to see how the body processes it and to observe any potential effects it may have on the symptoms of DM1. The trial aims to gather information on how well participants can tolerate the medication and to identify any side effects that may occur.

What is already known about the treatment

ATX-01 – This medication is administered intravenously and is currently being studied in clinical trials for its safety and effectiveness in treating myotonic dystrophy type 1 (DM1). It is in the early stages of research, specifically in Phase 1/2a trials, and is not yet widely recognized in medical literature. The main therapeutic indication for ATX-01 is to address symptoms associated with DM1. At the molecular level, it is designed to target and modify specific pathways involved in the disease process, although detailed mechanisms are still under investigation. It falls under the pharmacological classification of investigational drugs, as it is still being evaluated for its potential benefits and risks.

Investigated diseases

Myotonic Dystrophy Type 1 – Myotonic Dystrophy Type 1 (DM1) is a genetic disorder characterized by progressive muscle wasting and weakness. It often begins in adulthood and affects various body systems, including the skeletal muscles, heart, and eyes. Individuals with DM1 may experience prolonged muscle contractions, known as myotonia, which can make it difficult to relax muscles after use. Over time, the condition can lead to increased muscle stiffness and weakness, impacting daily activities. Other symptoms may include cataracts, heart conduction problems, and endocrine changes. The severity and progression of symptoms can vary widely among individuals.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-505363-37-00Protocol codeCT-ATX-01-DM1-1.1Estimated enrolment56 patientsSponsorArthex Biotech S.L.

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