Mucopolysaccharidosis Type II Observational

Study Overview
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Brief Summary
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This is an observational study planned to document prospectively disease manifestation and neurocognitive course in pediatric patients with a clinical presentation consistent with neuronopathic (severe) MPS II undergoing current standard of care and/or intrathecal Elaprase® for their condition. Some patients may be offered the opportunity to screen for a gene therapy study conducted by the same sponsor.

Detailed Description
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MPS II is a rare X-linked recessive genetic disease caused by mutations in the iduronate-2-sulfatase gene (IDS). Enzyme replacement therapy (ERT) with recombinant idursulfase (ELAPRASE®) is the only approved product for the treatment of Hunter syndrome; however, ERT as currently administered does not cross the blood brain barrier and is therefore unable to address the unmet need in MPS II patients with CNS (neurocognition and behavior) involvement. This is an observational study to document prospectively disease manifestation and neurocognitive course in pediatric patients with a clinical presentation consistent with neuronopathic (severe) MPS II undergoing current standard of care for their condition. Approximately forty pediatric subjects who have severe MPS II will be enrolled. Changes in neurodevelopmental parameters of cognitive, behavioral, and adaptive function over time will be the primary focus for a duration of 104 weeks.

Official Title
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A Prospective, Observational Study of Pediatric Patients With Neuronopathic Forms of MPS II (Hunter Syndrome)

Conditions
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Mucopolysaccharidosis II

Intervention / Treatment
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* Other: Observational


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Meets any of the following criteria: Has a clinical diagnosis of severe MPS II and has a documented mutation in IDS, OR Has a relative clinically diagnosed with severe MPS II who has the same IDS mutation as the subject, OR Has documented mutation(s) in IDS that in the opinion of the investigator is known to result in a neuronopathic phenotype Has sufficient communication capacity to complete the required protocol testing Patient's legal guardian must be willing and able to provide written, signed informed consent. Exclusion Criteria: Has had prior treatment with an AAV-based gene therapy product Is currently participating in a clinical trial of an investigational product for the treatment of MPS II with the exception of IT ELAPRASE trials; no investigational product may be taken starting 30 days or 5 half-lives of the investigational product prior to signing the ICF, whichever is longer

Ages Eligible for Study
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Minimum Age: 1 Month
Maximum Age: 8 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Observational<br>No Intervention | Other: Observational<br>* An observational study in subjects with the severe form of MPS II.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in neurodevelopmental parameters of cognitive function over time | Bayley Scales of Infant and Toddler Development Third Edition (BSID-III) | 104 weeks | 
| Changes in neurodevelopmental parameters of cognitive function over time | Mullen Scales of Early Learning (MSEL) Visual Reception Domain | 104 weeks | 
| Changes in neurodevelopmental parameters of adaptive behavior function over time | Vineland Adaptive Behavior Scales Second Edition (VABS-II) | 104 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in disease-specific biomarkers over time | I2S activity | 104 weeks | 
| Changes in disease-specific biomarkers over time | GAGs | 104 weeks | 
| Changes in quality of life | PedsQL | 104 weeks | 
| Changes in quality of life | ADL | 104 weeks | 
| Changes in Caregiver reported outcome | Family Burden of Illness Survey | 104 weeks | 
| Changes in sleep | SDSC | 104 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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MPS II, Gene Therapy, Hunter