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Study on Gene Therapy with Autologous Stem Cells and Drug Combination for Children with Mucopolysaccharidosis Type I Hurler Variant

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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 disorder called Mucopolysaccharidosis Type I, Hurler variant (MPS I Hurler). This condition affects the body's ability to break down certain sugars, leading to various health issues. The study is testing a new treatment called OTL-203, which involves using the patient's own blood stem cells that have been genetically modified. These cells are altered to include a gene that helps produce an enzyme called alpha-L-iduronidase, which is missing or not working properly in people with MPS I Hurler.

The purpose of the study is to evaluate the safety and tolerability of this gene therapy in children with MPS I Hurler. Participants will receive a conditioning treatment to prepare their body, followed by an infusion of the modified stem cells. The study will monitor the participants over time to see how well they tolerate the treatment and to check for any side effects. The study will also look at how well the treatment works in increasing the levels of the missing enzyme in the blood.

In addition to the main treatment, the study involves other medications such as Lenograstim, Plerixafor, Busulfan, Fludarabine, and Rituximab, which are used to support the treatment process. Some participants may receive a placebo instead of the active treatment to help compare the results. The study is expected to continue until 2027, with regular follow-ups to ensure the safety and effectiveness of the treatment.

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

    The trial begins with an initial assessment to confirm eligibility. This includes a review of medical history and tests to ensure adequate heart, kidney, liver, and lung function.

    Eligibility criteria include being between 28 days and 11 years old, having a confirmed diagnosis of Mucopolysaccharidosis Type I Hurler, and meeting specific health and donor availability requirements.

  2. Step 2

    Pre-treatment preparation

    Before starting the main treatment, a conditioning regimen is administered to prepare the body. This involves medications to suppress the immune system and make space in the bone marrow for new cells.

    Medications used include busulfan and fludarabine, both given intravenously. The exact dosage and schedule are determined by the medical team.

  3. Step 3

    Stem cell collection

    Stem cells are collected from the patient. These are special cells that can develop into different types of blood cells.

    The process involves using lenograstim and plerixafor to mobilize stem cells into the bloodstream, where they can be collected.

  4. Step 4

    Genetic modification

    The collected stem cells are genetically modified in a laboratory. This involves using a lentiviral vector to insert a healthy version of the IDUA gene into the cells.

    The modified cells are then prepared for infusion back into the patient.

  5. Step 5

    Infusion of modified cells

    The genetically modified stem cells are infused back into the patient through an intravenous line. This is the main part of the treatment.

    The goal is for these cells to engraft in the bone marrow and produce healthy blood cells.

  6. Step 6

    Post-treatment monitoring

    After the infusion, close monitoring is required to assess the safety and effectiveness of the treatment.

    This includes regular blood tests to check for engraftment and to measure IDUA enzyme activity levels. Monitoring for any side effects or complications is also conducted.

  7. Step 7

    Long-term follow-up

    Long-term follow-up is necessary to ensure the continued safety and effectiveness of the treatment.

    This involves periodic assessments over several years to monitor for any late-onset side effects or complications.

Who can join the trial?

8 criteria

  • The child's parent or legal guardian must provide written permission for the child to join the study.
  • Both boys and girls can participate.
  • The child must be between **28 days** old and **11 years** old.
  • The child must have a confirmed diagnosis of **Mucopolysaccharidosis type I Hurler (MPS IH)**, which is a specific genetic condition.
  • The child must have a **Lansky Index** score greater than **80%**. The Lansky Index is a way to measure how well a child can perform daily activities.
  • The child must need a **Hematopoietic Stem Cell Transplant (HSCT)**, which is a procedure to replace damaged or diseased bone marrow with healthy cells.
  • The child must not have a suitable sibling donor or a specific type of cord blood donor available after a one-month search. This requirement does not apply if the child's home country does not offer unrelated donor cord blood transplantation.
  • The child must have healthy heart, kidney, liver, and lung functions.

Who cannot join the trial?

5 criteria

  • Patients who have a different condition than Mucopolysaccharidosis type I Hurler cannot participate. This is a specific genetic disorder.
  • Patients who are not within the specified age range for the study cannot participate. The study is for children.
  • Patients who have not undergone a specific type of treatment called myeloablative and lymphoablative conditioning cannot participate. This treatment involves preparing the body for a transplant by reducing the immune system's activity.
  • Patients who are not able to receive the specific type of cell treatment being tested cannot participate. This involves using the patient's own cells that have been modified.
  • Patients who are not able to follow the study procedures or attend all required visits cannot participate.
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Investigated drugs

  • Autologous Hematopoietic Stem and Progenitor Cells

    are cells taken from the patient's own body. In this trial, these cells are genetically modified to include a specific gene, the IDUA gene, which is important for treating Mucopolysaccharidosis Type I, Hurler variant. The goal is to help the body produce the enzyme it lacks due to the condition.

  • IDUA Lentiviral Vector

    is a tool used to deliver the IDUA gene into the patient's stem cells. This vector helps insert the gene into the cells so they can start producing the necessary enzyme to treat the disease.

  • Myeloablative and Lymphoablative Conditioning Regimen

    is a treatment given before the modified cells are introduced back into the patient's body. This regimen helps prepare the body to accept the new cells by reducing the existing bone marrow and immune cells, making space for the new, modified cells to grow and function.

What is already known about the treatment

IDUA Lentiviral Vector – This medication is administered through an infusion of genetically modified autologous hematopoietic stem and progenitor cells. It is currently being studied in clinical trials for its safety and effectiveness in treating Mucopolysaccharidosis Type I, Hurler variant. The main therapeutic indication is to address the enzyme deficiency in this condition by introducing the human α-L-iduronidase gene into the patient's cells. At the molecular level, the mechanism involves the use of a lentiviral vector to deliver the gene, enabling the production of the missing enzyme. This medication falls under the pharmacological classification of gene therapy.

Investigated diseases

Mucopolysaccharidosis type I Hurler – This is a genetic disorder caused by a deficiency of the enzyme alpha-L-iduronidase, which is necessary for breaking down certain complex carbohydrates. As a result, these carbohydrates accumulate in various tissues and organs, leading to progressive damage. Symptoms often appear in early childhood and may include developmental delay, distinctive facial features, and organ enlargement. Over time, individuals may experience joint stiffness, heart problems, and respiratory issues. The disease progresses with increasing severity, affecting physical abilities and quality of life.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase I/IITrial ID2024-514870-29-00Protocol codeTigetT10_MPSIHEstimated enrolment8 patientsSponsorOrchard Therapeutics (Europe) Limited

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).