RegenXBio Posts Updated Data From Hunter Syndrome Gene Therapy Trial

Regenxbio Inc RGNX announced additional interim data from Cohorts 1-3 of Phase 1/2 trial of RGX-121 for patients up to 5 years old diagnosed with Mucopolysaccharidosis Type II (MPS II), 

• The data were shared at the 18th Annual WORLDSymposium.  
• RGX-121 is an investigational one-time gene therapy designed to deliver the gene that encodes the iduronate-2-sulfatase (I2S) enzyme using the AAV9 vector. 
• RGX-121 is reported to be well-tolerated across all cohorts with no drug-related serious adverse events (SAEs) in 13 patients dosed with RGX-121. 
• Biomarker data from patients in all three cohorts indicate encouraging signals of I2S enzyme activity in the CNS following one-time administration of RGX-121. 
• Most patients in all three cohorts demonstrated Heparan sulfate (HS) reductions in the CSF following RGX-121 administration at the last time point available, with dose-dependent reductions seen at Weeks 8 and 24 post-RGX-121 administration. 
• At eight weeks post-RGX-121 administration, the median reduction in CSF HS from baseline was 29.5% in Cohort 1, 42.3% in Cohort 2, and 67.3% in Cohort 3. 
• One patient in Cohort 3 who had data at 24 weeks post-administration demonstrated a CSF HS reduction from a baseline of 63.9%. 
• Measures of neurodevelopmental function from patients in Cohorts 1 and 2 demonstrate continued developmental skill acquisition up to two years after RGX-121 administration.
• Price Action: RGNX shares are down 0.55% at $27.37 during the market session on the last check Wednesday.