This study evaluates the safety of a gene therapy called RGX-121 in children with MPS II (Hunter syndrome). It enrolled children aged 5 and older with a documented neuronopathic form of the disease linked to mutations in the IDS gene. The study was conducted in Phase 1/Phase 2 and has been completed.
The summary above is a plain-language rendering of the official record. The original English title is shown for reference.
Criteria are reproduced from the ClinicalTrials.gov record in the original English. Only the trial team can determine eligibility.
Inclusion Criteria: Meets any of the following criteria: 1. Has a documented diagnosis of MPS II AND a neurocognitive testing score ≤ 1 ½ standard deviation (SD) from the test normative mean (BSID-III: 77 and MSEL Visual Reception: 35), OR 2. Has a documented diagnosis of MPS II AND has a decline of ≥ 1 standard deviation on serial neurocognitive testing administered between 3 to 36 months apart (BSID-III Cognitive or MSEL Visual Reception), OR 3. Has a relative clinically diagnosed with neuronopathic MPS II who has the same IDS mutation as the participant AND the participant in the opinion of a geneticist has inherited a neuronopathic form of MPS II, OR 4. Has documented mutation(s) in IDS that in the opinion of a geneticist is known to result in a neuronopathic phenotype AND in the opinion of a clinician has a neuronopathic form of MPS II Exclusion Criteria: 1. Has contraindications for intracisternal injection, intracerebroventricular injection, or lumbar puncture 2. Has contraindications for immunosuppressive therapy 3. Has any neurocognitive deficit not attributable to MPS II or diagnosis of a neuropsychiatric condition 4. Has had prior treatment with an AAV-based gene therapy product 5. If receiving ELAPRASE® via intrathecal (IT) administration, must agree to discontinue IT idursulfase for the duration of the study 6. Has experienced a serious hypersensitivity reaction to intravenous (IV) ELAPRASE® 7. Is currently failing to respond to idursulfase (ELAPRASE®) IV due to neutralizing anti-idursulfase antibodies 8. Has received any investigational product within 30 days of Day 1 or 5 half-lives before signing of the ICF, whichever is longer 9. Has a platelet count \<100,000 per microliter (µL), absolute neutrophil count \<1.0 × 103/µL, or aminotransferase (ALT) or aspartate aminotransferase (AST) \>3 × upper limit of normal (ULN) or total bilirubin \>1.5 × ULN at screening unless the participant has a previously known history of Gilbert's syndrome