RGX-121 for MPS II (Hunter Syndrome)

RGX-121 is our product candidate for the treatment of Mucopolysaccharidosis Type II (MPS II), also known as Hunter syndrome.

RGX-121 is designed to use the NAV® AAV9 vector to deliver the human iduronate-2-sulfatase (IDS) gene to the central nervous system (CNS).

MPS II is a rare, X-linked recessive disease caused by a deficiency in the lysosomal enzyme IDS. In severe forms of the disease, early developmental milestones may be met, but developmental delay is readily apparent by 18 to 24 months. Developmental progression begins to plateau between three and five years of age, with regression reported to begin around six and a half years.

Specific treatment to address the neurological manifestations of MPS II and prevent or stabilize cognitive decline remains a significant unmet medical need.

Delivery of the gene encoding the enzyme that is deficient within cells in the CNS could provide a permanent source of secreted IDS beyond the blood-brain barrier, allowing for long-term cross correction of cells throughout the CNS. We believe this strategy could also provide rapid IDS delivery to the brain, potentially preventing the progression of cognitive deficits that otherwise occur in Hunter syndrome patients.