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Study to Determine the Best Dose of Vesleteplirsen for Patients with Duchenne Muscular Dystrophy Suitable for Exon 51-Skipping Treatment

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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 Duchenne Muscular Dystrophy, a genetic disorder characterized by progressive muscle weakness and degeneration. The treatment being tested is called Vesleteplirsen (SRP-5051), which is administered through an intravenous infusion. This means the medication is given directly into a vein. The study aims to determine the best dose of Vesleteplirsen and to evaluate its effects on the levels of a protein called dystrophin in the muscles. Dystrophin is important for muscle strength and function, and the study is particularly interested in patients whose condition can benefit from a specific type of genetic treatment known as exon 51-skipping.

The study is divided into two parts. In the first part, participants will receive different doses of Vesleteplirsen to find the highest dose that can be tolerated safely. This part will help researchers understand how the body handles the medication and its safety profile. In the second part, participants will receive the dose determined from the first part, and researchers will measure the amount of dystrophin in the muscle tissue to see how well the treatment is working. The medication is given every four weeks, and the study will monitor participants over a period of time to gather comprehensive data.

Throughout the study, researchers will also keep track of any side effects or adverse events that participants may experience. This information is crucial for understanding the safety and effectiveness of Vesleteplirsen in treating Duchenne Muscular Dystrophy. The study is designed to provide valuable insights into how this treatment can potentially improve muscle function and quality of life for those affected by this condition.

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

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria related to Duchenne Muscular Dystrophy (DMD).

    Participants may have previously received Vesleteplirsen or be new to the treatment.

  2. Step 2

    Part A: dose determination

    In Part A, the focus is on determining the safe and tolerable dose of Vesleteplirsen (SRP-5051).

    The medication is administered through an intravenous (IV) infusion every 4 weeks.

    The goal is to find the maximum dose that can be tolerated without significant side effects.

  3. Step 3

    Monitoring and assessments in part A

    Participants are monitored for any adverse events over a period of up to 75 weeks.

    Blood and urine samples are collected to measure the concentration of Vesleteplirsen at various times after the infusion.

  4. Step 4

    Part B: dose expansion

    In Part B, the selected dose from Part A is used to evaluate its effect on dystrophin protein levels in muscle tissue.

    The medication continues to be administered IV every 4 weeks.

  5. Step 5

    Monitoring and assessments in part B

    The primary focus is on changes in dystrophin protein levels at Week 28.

    Participants are monitored for adverse events throughout the study, up to Week 304.

    Additional assessments include changes in exon-skipping levels and dystrophin-positive fibers.

Who can join the trial?

9 criteria

  • The study is for males only.
  • Participants must have a genetic diagnosis of Duchenne Muscular Dystrophy (DMD). This is a condition that affects muscles.
  • Participants should have a specific type of genetic change called an out-of-frame deletion mutation in the DMD gene. This means a part of the gene is missing, which affects how the gene works.
  • The genetic change must be suitable for a treatment called exon 51-skipping. This is a method used to help the gene work better.
  • Participants must have been on a stable dose of oral corticosteroids for at least 12 weeks before starting the study. Corticosteroids are medicines that help reduce inflammation and improve muscle strength.
  • If participants have not been on corticosteroids, they should not have taken them for at least 12 weeks before starting the study.
  • Participants must have stable lung function, with a forced vital capacity (FVC) of at least 40% of what is expected. FVC is a measure of how much air you can exhale after taking a deep breath.
  • Participants should not need a machine to help them breathe at night.
  • Participants who have previously been treated with a medication called Vesleteplirsen in Part A of this study or in a related study are eligible.

Who cannot join the trial?

3 criteria

  • Only males can participate, so females are excluded.
  • Participants must be within a specific age range, so those outside this range cannot join.
  • Individuals with certain health conditions that make them more vulnerable may not be eligible.
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Investigated drugs

SRP-5051 is a medication being studied for its potential to treat patients with Duchenne Muscular Dystrophy who can benefit from exon 51-skipping treatment. It is administered intravenously every four weeks. The study aims to determine the safety and tolerability of different doses of SRP-5051 and to find the maximum dose that patients can tolerate. Additionally, the study evaluates the effect of SRP-5051 on the level of dystrophin protein in skeletal muscle tissue, which is important for muscle function.

What is already known about the treatment

SRP-5051 – This medication is administered intravenously every four weeks and is currently being studied in clinical trials for its potential use in treating Duchenne Muscular Dystrophy, specifically for patients who can benefit from exon 51-skipping treatment. The main therapeutic indication is to increase dystrophin protein levels in skeletal muscle tissue, which is crucial for muscle function. At the molecular level, SRP-5051 works by skipping exon 51 during the mRNA processing of the dystrophin gene, allowing for the production of a functional dystrophin protein. It is classified pharmacologically as an exon-skipping therapy, a type of genetic medicine aimed at modifying the expression of specific genes.

Investigated diseases

Duchenne Muscular Dystrophy – Duchenne Muscular Dystrophy is a genetic disorder characterized by progressive muscle degeneration and weakness. It primarily affects boys and is caused by mutations in the dystrophin gene, which is crucial for maintaining muscle cell structure. Symptoms usually begin in early childhood, with affected individuals experiencing difficulty in walking, frequent falls, and muscle stiffness. As the disease progresses, muscle weakness spreads to the arms, neck, and other areas, leading to increased difficulty in movement. Over time, individuals may lose the ability to walk and require assistance with daily activities. The progression of muscle weakness can also impact respiratory and cardiac muscles, affecting breathing and heart function.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-509935-23-00Protocol code5051-201Estimated enrolment61 patientsSponsorSarepta Therapeutics Inc.

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