REGENXBIO Announces Positive Data from Pivotal Dose Level of RGX-121 Demonstrating Long-Term Systemic Effect
- Data from pivotal dose level demonstrates long-term, sustained reductions in CSF levels of HS D2S6, a key biomarker of brain disease in MPS II
- 80% of patients who received the pivotal dose discontinued intravenous enzyme replacement therapy or remained treatment-naïve
- Submission of a rolling BLA using the accelerated approval pathway on track for Q3 2024
The totality of evidence from the CAMPSIITE trial continues to support RGX-121 as the potential first gene therapy and one-time treatment for MPS II. In
"As we quickly approach the BLA filing for RGX-121, we are very pleased with the data presented at SSIEM demonstrating encouraging evidence of systemic activity and long-term reductions of CSF D2S6," said
Data Summary
In new, long-term data from the Phase I/II/III CAMPSIITE® trial, patients receiving RGX-121 at the pivotal dose level demonstrated an 85% median reduction of cerebrospinal fluid (CSF) levels of heparan sulfate (HS) D2S6, a key biomarker of brain disease activity, approaching normal levels and sustained for up to two years. Topline results presented earlier this year from the CAMPSIITE trial demonstrated that the pivotal phase of the trial met its primary endpoint with statistical significance. Pivotal results were consistent with data from the dose-finding phase of CAMPSIITE, in which the majority of patients were shown to be exceeding expectations in neurodevelopmental function compared to natural history data up to four years.
In the dose-finding part of the trial, investigators chose to discontinue standard-of-care intravenous enzyme replacement therapy (ERT) or to remain ERT-naïve for a majority of patients. At the pivotal dose level (dose level 3), 80% of patients were ERT-free at last time point, up to more than 18 months post-dosing. At dose level 2, 71% of patients were ERT-free at last time point, up to almost three years.
As of
"A potential one-time treatment that can allow these boys to exceed the natural history of this disease in their neurocognitive development, as well as the ability to remain off enzyme replacement therapy for multiple years represents a meaningful option for patients and their families," said Roberto Giugliani, M.D., Ph.D., Professor,
Data presented is available on the "Publications" section of the
About the CAMPSIITE® Trial
CAMPSIITE is a Phase I/II/III multicenter, open-label trial for boys aged four months up to five years with neuronopathic MPS II. The primary endpoint of the trial is measurement of CSF GAGs. Accurate and sensitive measurements of CSF GAGs, such as HS D2S6, have the potential to be considered a surrogate endpoint that is reasonably likely to predict clinical benefit in MPS II disease under the accelerated approval pathway, as buildup of GAGs in the CSF of MPS II patients correlates with clinical manifestations including neurodevelopmental deficits.
The pivotal program is using commercial-scale cGMP material from
About RGX-121
RGX-121 is a potential one-time AAV therapeutic for the treatment of boys with MPS II. RGX-121 expressed protein is structurally identical to normal I2S. RGX-21 Delivery of the IDS gene within cells in the CNS could provide a permanent source of secreted I2S beyond the blood-brain barrier, allowing for long-term cross correction of cells throughout the CNS.
RGX-121 has received Orphan Drug Product, Rare Pediatric Disease, Fast Track and Regenerative Medicine Advanced Therapy designations from the
About Mucopolysaccharidosis Type II (MPS II)
MPS II, or Hunter Syndrome, is a rare, X-linked recessive disease caused by a deficiency in the lysosomal enzyme iduronate-2-sulfatase (I2S) leading to an accumulation of glycosaminoglycans (GAGs), including heparan sulfate (HS) in tissues which ultimately results in cell, tissue, and organ dysfunction, including in the central nervous system (CNS). MPS II is estimated to occur in 1 in 100,000 to 170,000 births. In severe forms of the disease, early developmental milestones may be met, but developmental delay is readily apparent by 18 to 24 months. Specific treatment to address the neurological manifestations of MPS II remains a significant unmet medical need. Key biomarkers of I2S enzymatic activity in MPS II patients include its substrate HS D2S6, which has been shown to correlate with neurocognitive manifestations of the disorder.
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Contacts:
Corporate Communications
dcormack@regenxbio.com
Investors:
ICR Westwicke
339-970-2843
chris.brinzey@westwicke.com
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