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Study on the Safety and Effectiveness of Rebisufligene Etisparvovec for Patients with Mucopolysaccharidosis Type IIIA

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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 IIIA, also known as Sanfilippo syndrome type A. This condition affects the body's ability to break down certain sugars, leading to severe neurological symptoms. The trial is testing a new treatment called UX111, also known by its code name ABO-102. This treatment is a type of gene therapy, which involves introducing a healthy copy of a gene into the body to help produce a missing or faulty protein. In this case, the therapy aims to help the body produce the N-sulfoglucosamine sulfohydrolase protein, which is missing in people with this condition.

The purpose of the study is to evaluate the safety and effectiveness of UX111 in treating Mucopolysaccharidosis type IIIA. Participants in the study will receive the treatment through an injection into a vein, known as intravenous use. The study will monitor participants for any side effects and measure changes in certain substances in the body that are related to the disease. This will help researchers understand how well the treatment works and how safe it is for patients.

The study will take place over several years, with participants being closely monitored throughout the process. The goal is to gather enough information to determine if UX111 can be a viable treatment option for those affected by Mucopolysaccharidosis type IIIA. This research is important for developing new therapies that could improve the quality of life for patients with this challenging 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, the patient will be assessed to confirm a diagnosis of Mucopolysaccharidosis type IIIA. This involves checking for reduced SGSH enzyme activity and specific genetic mutations.

    The patient must meet age criteria, which vary depending on the cohort they are assigned to.

  2. Step 2

    Treatment administration

    The patient will receive the treatment known as ABO-102, which is a suspension for injection.

    The administration route is intravenous, meaning the medication is delivered directly into a vein.

  3. Step 3

    Monitoring and follow-up

    Throughout the trial, the patient will be monitored for any adverse effects. This includes tracking any treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs).

    The effectiveness of the treatment will be evaluated by measuring changes in cerebrospinal fluid (CSF) components, such as heparan sulfate and gangliosides.

  4. Step 4

    Developmental assessments

    The patient's cognitive and communication development will be assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (BSITD-III).

    These assessments will help determine any changes in cognitive and communication abilities over the course of the trial.

  5. Step 5

    Completion of the trial

    The trial is expected to conclude by July 31, 2027. At this point, all data will be collected and analyzed to evaluate the overall safety and efficacy of the treatment.

Who can join the trial?

6 criteria

  • The patient must have a confirmed diagnosis of **Mucopolysaccharidosis type IIIA (MPS IIIA)**. This is confirmed by two methods:
    • There should be no detectable or very low activity of the **SGSH enzyme** in a blood test.
    • A genetic test must show specific changes (mutations) in the **SGSH gene**.
    • The patient must be within certain age ranges:
      • For some groups, the patient can be from birth to 2 years old, or older than 2 years with a certain level of cognitive development.
      • For another group, the patient can be from 3 months to 2 years old, or older than 2 years with a certain level of cognitive development.
      • In some cases, patients older than 2 years and up to 5 years with lower cognitive development may also be included.
      • For a specific group, the patient's vaccination status must be up to date according to the guidelines of their country. This must be verified by their primary care doctor. The patient must also be willing to delay vaccines for a certain period after completing a specific medication, unless there is a medical reason not to.

Who cannot join the trial?

7 criteria

  • Patients with any other serious medical condition that might interfere with the study.
  • Patients who have had a recent infection that could affect their participation.
  • Patients who are currently taking medications that might interfere with the study treatment.
  • Patients who have participated in another clinical trial recently.
  • Patients who have a history of allergic reactions to similar treatments.
  • Patients who are unable to comply with the study procedures.
  • Patients who have a condition that the study doctors believe would make it unsafe for them to participate.
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Investigated drugs

UX111 (also known as ABO-102) is a gene therapy product being studied for the treatment of mucopolysaccharidosis (MPS) IIIA. This therapy involves using a modified virus to deliver a healthy copy of a gene to the patient's cells. The goal is to help the body produce an enzyme that is missing or not working properly in people with MPS IIIA, potentially improving symptoms and slowing the progression of the disease.

What is already known about the treatment

UX111 (ABO-102) – This medication is administered through gene therapy, specifically using a viral vector to deliver a healthy copy of the SGSH gene to patients. It is currently being studied in clinical trials for its effectiveness and safety in treating Mucopolysaccharidosis type IIIA, a rare genetic disorder. The main therapeutic indication is to address the underlying genetic cause of this condition by enabling the production of the missing enzyme. At the molecular level, the mechanism involves the introduction of the correct gene sequence into the patient's cells, allowing for normal enzyme production and function. UX111 is classified under gene therapy products, representing a novel approach in the treatment of genetic disorders.

Investigated diseases

Mucopolysaccharidosis type IIIA – This is a rare genetic disorder that affects the body's ability to break down certain sugar molecules, leading to their accumulation in cells. It primarily impacts the central nervous system, causing progressive neurological decline. Children with this condition often experience developmental delays, behavioral issues, and sleep disturbances. Over time, the accumulation of these molecules can lead to more severe symptoms, including loss of motor skills and cognitive abilities. The disease is inherited in an autosomal recessive pattern, meaning both parents must carry a copy of the mutated gene. As the condition progresses, individuals may require increasing levels of care and support.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase I/IITrial ID2023-510032-37-00Protocol codeABT-001Estimated enrolment36 patientsSponsorUltragenyx Pharmaceutical Inc.

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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).