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Study on Long-Term Safety and Efficacy of VX-670 for Adults with Myotonic Dystrophy Type I

Verified siteInvestigationalNo placebo
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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 the long-term effects of a treatment called VX-670 for individuals with Myotonic Dystrophy Type I. Myotonic Dystrophy is a genetic disorder that affects muscle function, leading to symptoms such as muscle weakness and stiffness. The treatment being tested, VX-670, is administered as a solution for injection or infusion, which means it is given directly into the bloodstream through a vein.

The purpose of this study is to evaluate how safe and tolerable VX-670 is for patients over an extended period. Participants in the study will receive the treatment and be monitored for any side effects or changes in their health. The study will also look at how the body processes the treatment and its effects on the disease. This includes checking for any changes in muscle tissue and the presence of the treatment in the blood and muscles.

Throughout the study, participants will have regular check-ups to monitor their health, including assessments of vital signs, heart function through electrocardiograms (ECGs), and laboratory tests. The study aims to provide valuable information on the long-term use of VX-670 for managing Myotonic Dystrophy Type I, helping to understand its potential benefits and any risks involved.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, an informed consent form must be signed and dated. This form confirms understanding and agreement to participate in the study.

    Eligibility requires completion of a previous VX-670 study, specifically having received at least two doses of the study drug in Study 001, Part B.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to evaluate current health status. This includes checking vital signs, performing an electrocardiogram (ECG), and conducting laboratory tests.

    These assessments help ensure the safety and suitability for continued participation in the study.

  3. Step 3

    Treatment administration

    The study involves receiving the medication VX-670 as a solution for injection/infusion. This is administered through a vein, a process known as intravenous administration.

    The frequency and dosage of the medication will be determined by the study protocol and communicated during the study visits.

  4. Step 4

    Ongoing monitoring

    Regular visits are scheduled to monitor health and response to the medication. This includes checking for any side effects, known as adverse events, and assessing overall well-being.

    Vital signs, ECGs, and laboratory tests will be repeated at these visits to ensure safety and tolerability of the treatment.

  5. Step 5

    Muscle biopsy

    At Week 24, a muscle biopsy of the tibialis anterior muscle will be performed. This procedure involves taking a small sample of muscle tissue to study changes from the baseline.

    The concentration of VX-670 and another compound, PMO-0221a, will be measured in both plasma and muscle tissues.

  6. Step 6

    Completion of study

    The study is estimated to end on November 16, 2029. Upon completion, a final assessment will be conducted to evaluate long-term safety and efficacy of the treatment.

    Participants will receive information about the study results and any further steps if necessary.

Who can join the trial?

5 criteria

  • The person must have **Myotonic Dystrophy** (also known as DM1).
  • The person, or someone who can help them if they cannot write, must sign and date a form that shows they agree to join the study. This is called an **informed consent form**.
  • The person must have finished a previous study with the study drug **VX-670**. For those in a specific part of the previous study, they must have received at least two doses of the study drug.
  • The person must be willing and able to attend scheduled visits, follow the treatment plan, adhere to study rules, undergo safety tests, follow guidelines for preventing pregnancy, and participate in other study procedures.
  • Both **men and women** can participate in the study.

Who cannot join the trial?

3 criteria

  • Patients who do not have Myotonic Dystrophy cannot participate.
  • Patients who are not within the specified age range cannot participate.
  • Patients who are part of a vulnerable population cannot participate.
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Investigated drugs

VX-670 is a medication being studied for its potential to help people with Myotonic Dystrophy Type I, a condition that affects the muscles and other systems in the body. This medication is being tested to see if it is safe and well-tolerated over a long period. Researchers are also looking at how the body processes the medication and how it affects the body. The goal is to understand if VX-670 can help improve the symptoms of this condition and how it works in the body over time.

What is already known about the treatment

VX-670 – VX-670 is administered orally in the form of a tablet and is currently being studied in clinical trials for its potential use in treating Myotonic Dystrophy Type I, a genetic disorder that affects muscle function. The medication is in the experimental phase, and researchers are evaluating its long-term safety, tolerability, and effectiveness. VX-670 works by targeting specific molecular pathways involved in the disease, aiming to improve muscle function and reduce symptoms. It is classified as an investigational drug, meaning it is not yet approved for general medical use but is being tested for its potential benefits in clinical settings.

Investigated diseases

Myotonic Dystrophy – Myotonic Dystrophy is a genetic disorder characterized by progressive muscle wasting and weakness. It primarily affects the skeletal muscles, but can also impact the heart, eyes, and endocrine system. The disease progresses with muscle stiffness and difficulty relaxing muscles after use, known as myotonia. Over time, individuals may experience increased muscle weakness and atrophy, particularly in the face, neck, and lower legs. Other symptoms can include cataracts, cardiac conduction defects, and hormonal changes. The progression of the disease varies widely among individuals, with symptoms often worsening over time.
Trial detailsLast updated 4 Oct 2026
Age18+ yearsPhasePhase ITrial ID2024-517983-47-00Protocol codeVX-24-670-101Estimated enrolment39 patientsSponsorVertex Pharmaceuticals Inc.

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