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Not yet recruitingRare disease

Long‑Term Monitoring of Malignancy Risk in Early‑Onset Metachromatic Leukodystrophy Patients Treated with atidarsagene autotemcel

Verified siteRegistered drugNo placebo
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What is this trial about?

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

Metachromatic leukodystrophy is a rare inherited disorder that slowly damages the protective coating of nerve cells, leading to problems with movement, learning and daily activities. The study uses a gene‑therapy product called OTL-200, which contains specially prepared cells that are given through an intravenous infusion to try to replace the missing enzyme and slow the disease’s progression.

The purpose of the study is to watch for any long‑term safety concerns, specifically the chance of developing malignancy caused by insertional oncogenesis, a process where the therapy’s genetic material might unintentionally trigger cancer. After receiving the infusion, participants will have regular sample collections over many years so doctors can check for signs of cancer or unusually high levels of altered cells. This monitoring helps ensure that any potential risks are identified early while the treatment’s benefits continue to be evaluated.

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

    Enrollment and baseline assessment

    After joining the study you provide written consent and undergo a baseline medical evaluation that includes a review of your health history, physical examination, and laboratory tests.

    Samples of blood and other tissues are collected at this time to establish reference values before receiving any study medication.

  2. Step 2

    Administration of <b>libmeldy</b> (<b>atidarsagene autotemcel</b>)

    The study medication is given as an intravenous infusion.

    The dose is 30,000,000 cells per kilogram of your body weight, delivered in a single infusion session.

    The infusion is performed in a clinical setting by qualified staff.

  3. Step 3

    Immediate post‑infusion monitoring

    Following the infusion you are observed for several hours to monitor vital signs, any immediate reactions, and overall tolerance of the medication.

    Additional blood samples may be taken during this period to evaluate early responses.

  4. Step 4

    Scheduled follow‑up visits and sample collection

    You will attend follow‑up visits at week 1, week 4, week 12, and then every six months for the duration of the study.

    At each visit blood and, when required, other tissue samples are collected to monitor for signs of malignancy related to insertional oncogenesis.

    Clinical assessments, including physical examinations and laboratory tests, are performed at each visit.

  5. Step 5

    Annual long‑term monitoring

    Once a year you undergo a comprehensive evaluation that may include imaging studies, detailed blood analyses, and additional sample collections.

    The purpose of these annual visits is to continue surveillance for any late‑appearing malignancies and to assess overall health.

  6. Step 6

    Study completion and final assessment

    The study is scheduled to end on 2035‑07‑31.

    At the final visit a complete set of assessments and samples is obtained to determine the long‑term safety outcomes of the treatment.

Who can join the trial?

6 criteria

  • The patient must have early‑onset Metachromatic leukodystrophy (MLD) and be enrolled in the LongTERM‑MLD OTL‑200‑10 Study as part of Group 1, which means they are receiving the study drug OTL‑200 as part of the clinical development program.
  • The patient (or, if the patient is a child, the patient’s parent or legal guardian) must be able and willing to sign a written informed consent form, which is a document that explains the study and confirms that they agree to take part.
  • The participant must be a patient with the disease; healthy volunteers are not eligible.
  • Both males and females are allowed to join the study.
  • The study includes children, so participants as young as 2 years old can be eligible.
  • Because the study involves children, it is considered a vulnerable population, meaning extra care is taken to protect their safety and rights.

Who cannot join the trial?

1 criterion

  • There are no reasons that would exclude a patient from participating in this study.
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Investigated drugs

Libmeldy (atidarsagene autotemcel)
Libmeldy is a gene therapy that uses the patient’s own blood stem cells. These cells are taken out, modified in the laboratory to carry a healthy copy of the gene that is missing in people with metachromatic leukodystrophy, and then returned to the patient through an intravenous infusion. The goal of the therapy is to provide the missing enzyme that helps break down certain fats in the brain, which can slow or stop the disease’s progression. In this study, researchers are closely watching patients who receive Libmeldy to see if there is any long‑term risk of developing cancer due to the way the gene is inserted into the cells.

What is already known about the treatment

ATIDARSAGENE AUTOTEMCEL - It is given as an intravenous infusion of a cell suspension, where the dose is 30 million cells per kilogram. It is an approved gene therapy for metachromatic leukodystrophy and is listed as an orphan drug. It works by adding a healthy copy of the ARSA gene into the patient’s own blood stem cells, which then produce the missing enzyme needed to break down certain fats in the brain. It belongs to the class of gene‑modified autologous cellular therapies.

Investigated diseases

Metachromatic leukodystrophy - Metachromatic leukodystrophy is a rare inherited disorder that affects the protective covering of nerve fibers in the brain and spinal cord. It is caused by a deficiency of an enzyme that leads to a buildup of fatty substances in these coverings. As the fatty material accumulates, the nerve fibers become damaged, which interferes with the transmission of signals. Children may first notice problems with walking, coordination, and speech, and the difficulties gradually spread to other functions. Over time, muscle weakness, loss of sensation, and difficulty with thinking and learning can develop.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522275-28-00Protocol codeOTL-200-11Estimated enrolment35 patientsSponsorOrchard Therapeutics (Europe) Limited

sourced from the EU Clinical Trials Register and site verification

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