NCT04571970

RGX-121 Gene Therapy in Children 5 Years of Age and Over With MPS II (Hunter Syndrome)

A Phase I/II Multicenter, Open-Label Study to Evaluate the Safety, Tolerability, and Pharmacodynamics of RGX-121 in Children 5 Years of Age and Older With MPS II (Hunter Syndrome)

• Status: Completed
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 6 (actual)
• Sponsor: REGENXBIO Inc. · Industry
• Sex: Male
• Age: 5 Years – 17 Years
• Healthy volunteers: Not accepted

Summary

RGX-121 is a gene therapy which is designed to deliver a functional copy of the iduronate-2-sulfatase (IDS) gene to the central nervous system. This study is a phase I/II study to determine whether RGX-121 is safe, well tolerated, and potentially effective in children five years of age and over who have severe MPS II.

Detailed description

MPS II is a rare X-linked recessive genetic disease caused by mutations in the iduronate-2-sulfatase (IDS) gene. 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. RGX-121 is designed to deliver a healthy gene to cells in the CNS and iduronate-2-sulfatase (I2S) may then be secreted by transduced cells which may cross-correct non-transduced cells by taking up the functional enzyme. This is a Phase I/II, multicenter, open-label, single arm study of RGX-121. Approximately 6 children (≥ 5 years to \< 18 years of age) who have severe (neuronopathic) MPS II could be enrolled into a single dose cohort and will receive a single dose of RGX-121 administered by IC or ICV injection. Safety will be the primary focus for the initial 24 weeks after treatment (primary study period). Following completion of the primary study period, participants will continue to be assessed (safety and efficacy) for up to a total of 104 weeks following treatment with RGX-121.

Conditions

• Mucopolysaccharidosis Type II (MPS II)

Interventions

Type	Name	Description
GENETIC	RGX-121	Recombinant adeno-associated virus serotype 9 capsid containing human iduronate-2-sulfatase expression cassette

Timeline

• Start date: 2021-03-11
• Primary completion: 2023-05-09
• Completion: 2024-05-23
• First posted: 2020-10-01
• Last updated: 2025-01-28

Locations

2 sites across 2 countries: United States, Canada

Regulatory

• FDA-regulated drug study