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Study on the Safety and Effectiveness of AT132 Gene Therapy for Patients with X-Linked Myotubular Myopathy

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 a rare genetic condition called X-linked Myotubular Myopathy (XLMTM). This condition affects muscle strength and function, primarily in young boys. The study is testing a new treatment called AT132, which is a type of gene therapy. Gene therapy involves using a specially designed virus to deliver a healthy copy of a gene into the body. In this case, the therapy uses a viral vector known as AAV serotype 8 to deliver the human MTM1 gene to patients. This approach aims to address the genetic cause of XLMTM by providing the body with the correct gene needed for muscle function.

The purpose of the study is to determine the best dose of AT132 and to confirm its safety and effectiveness in treating XLMTM. Participants in the study will receive the treatment through an intravenous infusion, which means the solution is delivered directly into the bloodstream. The study will follow participants over time to monitor changes in their condition, including their need for ventilator support and their ability to sit independently. Some participants may receive a placebo as part of the study design.

The study will take place over several years, with regular check-ups to assess the health and progress of the participants. Researchers will look at various health indicators, such as muscle strength, breathing ability, and overall quality of life, to understand how well the treatment works. The ultimate goal is to improve the lives of those affected by XLMTM by reducing symptoms and enhancing muscle function.

The research process

The trial runs in 4 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, the patient is confirmed to have a diagnosis of X-linked Myotubular Myopathy (XLMTM) due to a mutation in the MTM1 gene.

    The patient is male and under 5 years old at the time of receiving the treatment.

    The patient requires mechanical ventilatory support, which may range from full-time mechanical ventilation to noninvasive support during sleep.

  2. Step 2

    Treatment administration

    The patient receives the treatment AT132, which is a gene therapy delivered through an intravenous infusion.

    The active substance in the treatment is resamirigene bilparvovec.

  3. Step 3

    Monitoring and assessment

    The primary goal is to observe changes in the hours of ventilation support needed by the patient at Week 24.

    Secondary assessments include the ability to sit independently for at least 30 seconds, reduction in ventilator support, and changes in neuromuscular function and quality of life.

    Safety is monitored through adverse events, laboratory tests, and other health assessments.

  4. Step 4

    Follow-up

    The study continues with regular follow-ups to assess the long-term effects of the treatment.

    The estimated end date for the study is January 29, 2030.

Who can join the trial?

9 criteria

  • The patient must have a diagnosis of **X-linked Myotubular Myopathy (XLMTM)**, which is confirmed by a genetic test showing a mutation in the **MTM1 gene**.
  • The patient must be male.
  • The patient must be younger than 5 years old at the time of receiving the treatment.
  • The patient must need help with breathing using a machine. This can range from needing a machine all day to needing help only during sleep with devices like **CPAP** (Continuous Positive Airway Pressure) or **BiPAP** (Bilevel Positive Airway Pressure).
  • If the patient needs a machine to help with breathing most of the day, they must have or be willing to have a **cuffed tracheostomy tube**. This is a tube placed in the windpipe to help with breathing tests.
  • The patient must have a breathing machine setting called **PEEP** (Positive End-Expiratory Pressure) that is less than 8 cm H2O during the screening.
  • The patient's parent or legal guardian must sign a consent form agreeing to the patient's participation in the study.
  • The patient and their parent or guardian must be willing and able to attend study visits and follow study procedures.
  • In France, the patient must weigh at least 4.8 kg.

Who cannot join the trial?

3 criteria

  • Only males can participate in this study. Females are not eligible.
  • Participants must be within a specific age range, which is not specified here.
  • Individuals who do not have X-linked Myotubular Myopathy (XLMTM) cannot participate. This is a genetic condition that affects muscle strength.
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Investigated drugs

AT132 is a gene therapy being studied for its potential to treat X-Linked Myotubular Myopathy (XLMTM), a genetic disorder that affects muscle strength. This therapy uses a virus called AAV8 to deliver a healthy copy of the gene that is missing or not working properly in patients with XLMTM. The goal of AT132 is to improve muscle function and overall health in patients by addressing the underlying genetic cause of the disease.

What is already known about the treatment

AT132 – This medication is administered as a gene therapy delivered through an intravenous infusion. It is currently being studied in clinical trials for its safety and effectiveness in treating X-linked Myotubular Myopathy (XLMTM), a rare genetic disorder. The main therapeutic indication for AT132 is to address muscle weakness associated with XLMTM. At the molecular level, AT132 works by delivering a functional copy of the MTM1 gene to muscle cells, which helps in the production of myotubularin, a protein essential for normal muscle function. It is classified as a gene therapy product.

Investigated diseases

X-linked Myotubular Myopathy – This is a rare genetic disorder that primarily affects skeletal muscles, leading to muscle weakness and respiratory difficulties. It is caused by mutations in the MTM1 gene, which is responsible for producing a protein essential for normal muscle function. The condition is typically evident at birth or in early infancy, with symptoms including hypotonia (reduced muscle tone) and difficulties with feeding and breathing. As the disease progresses, affected individuals may experience delayed motor milestones and require assistance with ventilation. The severity of symptoms can vary, but the condition is generally characterized by significant muscle weakness and potential respiratory complications.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase IVTrial ID2024-512637-32-00Protocol codeATX-MTM-002Estimated enrolment27 patientsSponsorAstellas Gene Therapies Inc.

sourced from the EU Clinical Trials Register and site verification

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