Benzinga | May 14, 2021 02:41PM EDT

Regenxbio's Hunter Syndrome Gene Therapy Shows Efficacy Signals, Cognitive Development Up To Two Years

* Regenxbio Inc (NASDAQ: RGNX) has announced a safety update and additional positive interim data from its ongoing Phase 1/2 trial of RGX-121 to treat patients up to 5 years old diagnosed with Mucopolysaccharidosis Type II (MPS II), also known as Hunter Syndrome.

* The data will be presented at the American Society of Gene and Cell Therapy 24th Annual Meeting.

* Heparan sulfate (HS) levels are a key biomarker of I2S enzyme activity. The patients in Cohorts 1 and 2 demonstrated decreased HS in the cerebrospinal fluid (CSF) for up to 2 years following one-time administration of RGX-121.

* Combined median reductions from baseline were 30.3% at Week 8 and 35.0% at the last time point available for each patient.

* These patients also demonstrated decreased levels of D2S6, a component of HS, up to 2 years, with median reductions of 44.1% at Week 8 and 40.4% at the last timepoint available for each patient.

* Continuous neurocognitive development was observed up to two years after RGX-121 administration.

* Five patients have assessments of neurodevelopment function at time points beyond six months, and of those patients, four have continued to demonstrate neurocognitive development.

* Two patients in Cohort 1 discontinued enzyme replacement therapy (ERT) over one year after administration of RGX-121.

* 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. It is administered directly to the central nervous system.

* Price Action: RGNX shares are up 3.19% at 36.42 during the market session on the last check Friday.