RGX-121 Gene Therapy in Patients With MPS II (Hunter Syndrome)
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03566043 |
Recruitment Status :
Recruiting
First Posted : June 21, 2018
Last Update Posted : May 6, 2022
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Mucopolysaccharidosis Type II (MPS II) | Genetic: RGX-121 | Phase 1 Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 18 participants |
Allocation: | Non-Randomized |
Intervention Model: | Sequential Assignment |
Intervention Model Description: | Dose escalation |
Masking: | None (Open Label) |
Masking Description: | Open Label |
Primary Purpose: | Treatment |
Official Title: | A Phase I/II Multicenter, Open-Label Study to Evaluate the Safety, Tolerability, and Pharmacodynamics of RGX-121 in Pediatric Subjects With MPS II (Hunter Syndrome) |
Actual Study Start Date : | September 27, 2018 |
Estimated Primary Completion Date : | May 2022 |
Estimated Study Completion Date : | May 2024 |

Arm | Intervention/treatment |
---|---|
Experimental: RGX-121 Dose 1
1.3x10^10 GC/g brain mass of RGX-121
|
Genetic: RGX-121
Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette |
Experimental: RGX-121 Dose 2
6.5x10^10 GC/g brain mass of RGX-121
|
Genetic: RGX-121
Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette |
Experimental: RGX-121 Dose 2 Expanded Cohort
6.5x10^10 GC/g brain mass of RGX-121
|
Genetic: RGX-121
Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette |
Experimental: RGX-121 Dose 3
2.0x10^11 GC/g brain mass of RGX-121
|
Genetic: RGX-121
Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette |
Experimental: RGX-121 Dose 3 Expanded Cohort
2.0x10^11 GC/g brain mass of RGX-121 (Poly-A-specific PCR assay) equivalent to, 2.9x10^11 GC/g brain mass of RGX-121 (transgene-specific PCR assay)
|
Genetic: RGX-121
Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette |
- Safety: Number of participants with treatment-related adverse events and serious adverse events [ Time Frame: 24 Weeks ]Number of participants with treatment-related adverse events and serious adverse events as assessed by CTCAE (Version 4.03).
- Safety: Number of participants with treatment-related adverse events [ Time Frame: 104 Weeks ]Number of participants with treatment-related adverse events as assessed by CTCAE (Version 4.03).
- Biomarkers [ Time Frame: Baseline, Week 2, Week 4, Week 8, Week 24, Week 48, Week 56, Week 104 ]Change from baseline in Glycosaminoglycan levels (ng/mL)
- Biomarkers [ Time Frame: Baseline, Week 1, Week 2, Week 4, Week 8, Week 24, Week 32, Week 48, Week 56, Week 104 ]Change from baseline in iduronate-2-sulfatase activity
- Change in neurodevelopmental parameters [ Time Frame: Baseline, Week 48, Week 78, Week 104 ]Change from baseline in neurodevelopment parameters of cognitive, behavioral and adaptive function as measured by the Bayley Scales of Infant and Toddler Development, 3rd Edition (BSID-III) or Kaufman Assessment Battery for Children, 2nd Edition (KABC-II). Based on their mean age equivalence score on the Vineland Adaptive Behavior Scales (outcome #7) , the child will be assessed using either the BSID-III (for scores of <36 months or </=42 months and unable to complete the KABC-II) OR the KABC-II (for scores of >/= 36 months).
- Change in neurodevelopmental parameters [ Time Frame: Baseline, Week 48, Week 78, Week 104 ]Change from baseline in neurodevelopment parameters of cognitive, behavioral and adaptive function as measured by the Mullen Scales of Early Learning (MSEL)
- Change in neurodevelopmental parameters [ Time Frame: Baseline, Week 48, Week 78, Week 104 ]Change from baseline in neurodevelopment parameters of cognitive, behavioral and adaptive function as measured by the Vineland Adaptive Behavior Scales, 2nd Edition (VABS-II), Comprehensive Interview Form

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 4 Months to 5 Years (Child) |
Sexes Eligible for Study: | Male |
Gender Based Eligibility: | Yes |
Gender Eligibility Description: | Genetic-based gender identity |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Must meet any of the following criteria:
- a. Has a documented diagnosis of MPS II AND has a neurocognitive testing score ≤ 77 (Bayley or Kaufman), OR
- b. 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 (Bayley or Kaufman) OR
- c. Has a relative clinically diagnosed with severe MPS II who has the same IDS mutation as the subject AND in the opinion of a geneticist has inherited a severe form of MPS II OR
- d. Has documented mutation(s) in IDS that in the opinion of a geneticist is always known to result in a neuronopathic phenotype AND in the opinion of a clinician has a severe form of MPS II
- Patient's legal guardian must be willing and able to provide written, signed informed consent.
- Is ≥4 months to <5 years of age.
Exclusion Criteria:
- Has contraindications for intracisternal injection, intracerebroventricular injection, or lumbar puncture
- Has contraindications for immunosuppressive therapy
- Has neurocognitive deficit not attributable to MPS II or diagnosis of a neuropsychiatric condition
- Has a (cerebral) ventricular shunt that may impact the proper dosing of the subject
- Received hematopoietic stem cell transplantation
- Has had prior treatment with an AAV-based gene therapy product
- Received ELAPRASE® via intrathecal (IT) administration within 4 months of signing the ICF or experienced a serious hypersensitivity reaction to ELAPRASE®
- Has received any investigational product within 30 days of Day 1 or 5 half-lives before signing the ICF, whichever is longer
- Has a platelet count <100,000 per microliter (µL), absolute neutrophil count <1.3 × 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 subject has a previously known history of Gilbert's syndrome

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03566043
Contact: Patient Advocacy | 866-860-0117 | MPSII@regenxbio.com |
United States, California | |
University of California San Francisco, Benioff Children's Hospital | Recruiting |
Oakland, California, United States, 94609 | |
Contact: Matt Thura matt.thura@ucsf.edu | |
Principal Investigator: Dr. Paul Harmatz | |
United States, Pennsylvania | |
Children's Hospital of Philadelphia | Recruiting |
Philadelphia, Pennsylvania, United States, 19104 | |
Contact: Diana Julca Aguinaga julcad@chop.edu | |
Principal Investigator: Dr. Can Ficicioglu | |
Children's Hospital of Pittsburgh - UPMC: Program for Neurodevelopment in Rare Disorders | Recruiting |
Pittsburgh, Pennsylvania, United States, 15224 | |
Contact: Jodi Martin - Research Coordinator 412-692-6351 sausjl@upmc.edu | |
Contact: Dr. Maria Escolar - Principal Investigator maria.escolar@chp.edu | |
Brazil | |
Hospital de Clinicas de Porto Alegre | Recruiting |
Porto Alegre, RS, Brazil, 90035-903 | |
Contact: Larissa Pozzebon da Silva 55 51 3359-6341 lapsilva@hcpa.edu.br | |
Principal Investigator: Dr. Roberto Giugliani |
Responsible Party: | Regenxbio Inc. |
ClinicalTrials.gov Identifier: | NCT03566043 |
Other Study ID Numbers: |
RGX-121-101 |
First Posted: | June 21, 2018 Key Record Dates |
Last Update Posted: | May 6, 2022 |
Last Verified: | November 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
MPS II gene therapy Hunter |
Mucopolysaccharidosis II Mucopolysaccharidoses Carbohydrate Metabolism, Inborn Errors Metabolism, Inborn Errors Genetic Diseases, Inborn Lysosomal Storage Diseases Mucinoses Connective Tissue Diseases |
Metabolic Diseases Mental Retardation, X-Linked Intellectual Disability Neurobehavioral Manifestations Neurologic Manifestations Nervous System Diseases Genetic Diseases, X-Linked Heredodegenerative Disorders, Nervous System |