ROCKVILLE -
'We are thrilled to see that RGX-202 is demonstrating strong microdystrophin expression across a wide range of patients,' said
Safety Update
As of
Biomarker Data
In new data from the third patient, aged 6.6 years, who received RGX-202 at dose level 1, RGX-202 microdystrophin expression was measured to be 83.4% compared to control at three months. A reduction from baseline in serum creatinine kinase (CK) levels of 93% was observed at ten weeks.
All three patients, at dose level 1, who completed three-month trial assessments indicate encouraging increases in expression of RGX-202 microdystrophin and reduction from baseline in serum CK levels, supporting evidence of clinical improvement.
RGX-202 microdystrophin levels were measured using an automated and precise western blot method (Jess), and comparable results were confirmed with a proprietary liquid chromatography-mass spectrometry (LC-MS) method. Elevated CK levels are associated with muscle injury and are uniformly elevated in patients with Duchenne. The mean (SD) RGX-202 microdsytrophin expression levels (change from baseline) at three months following RGX-202 administration were 44.4% (n=3, SD:36.5%).
Clinical Program Updates
REGENXIO expects to make a pivotal dose determination in mid-2024. The Company also expects to share initial strength and functional assessment data for both dose levels and the initiation of a pivotal trial in the second half of 2024. The Company plans to use RGX-202 microdystrophin expression as a surrogate endpoint to support a Biologics License Application (BLA) filing using the accelerated approval pathway.
'On our call this afternoon, we look forward to discussing these new clinical results and also reaffirming our guidance for the submission of a BLA this year for RGX-121 for the treatment of MPS II. The exciting topline pivotal data supporting this submission will be released later this morning in conjunction with a presentation at the 20th Annual WORLDSymposium,' said Mills.
About RGX-202
RGX-202 is designed to deliver a transgene for a novel microdystrophin that includes the functional elements of the C-Terminal (CT) domain found in naturally occurring dystrophin. Presence of the CT domain has been shown in preclinical studies to recruit several key proteins to the muscle cell membrane, leading to improved muscle resistance to contraction-induced muscle damage in dystrophic mice. Additional design features, including codon optimization and reduction of CpG content, may potentially improve gene expression, increase translational efficiency and reduce immunogenicity. RGX-202 is designed to support the delivery and targeted expression of genes throughout skeletal and heart muscle using the NAV AAV8 vector, a vector used in numerous clinical trials, and a well-characterized muscle-specific promoter (Spc5-12).
About Duchenne Muscular Dystrophy
Duchenne is a severe, progressive, degenerative muscle disease, affecting 1 in 3,500 to 5,000 boys born each year worldwide. Duchenne is caused by mutations in the Duchenne gene which encodes for dystrophin, a protein involved in muscle cell structure and signaling pathways. Without dystrophin, muscles throughout the body degenerate and become weak, eventually leading to loss of movement and independence, required support for breathing, cardiomyopathy and premature death.
About
FORWARD-LOOKING STATEMENTS
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Contact:
Email: DCORMACK@REGENXBIO.COM
Tel: 339-970-2843
Email: CHRIS.BRINZEY@WESTWICKE.COM
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