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Regenxbio presents phase 1 data for wet AMD gene therapy
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CHICAGO — The 6-month results of an ongoing phase 1 study evaluating RGX-314 gene therapy for patients with wet AMD showed positive safety and patient tolerability outcomes, according to a speaker here.
The therapy is designed to deliver a gene encoding for an anti-VEGF fab protein. The therapy is delivered subretinally, and the RGX-314 therapy uses a proprietary gene delivery platform, hypothesized to deliver longer and higher protein levels with a lower immune response, Jeffrey Heier, MD, lead researcher of the study said at a Regenxbio press briefing after he presented the data at Retina Subspecialty Day preceding the American Academy of Ophthalmology meeting.
“RGX-314 uses an NAV-AAV8 vector, which delivers a gene encoding for a monoclonal antibody anti-VEGF fragment. Most of the studies to date have used AAV2; this has been the gene vector of choice because the safety had been demonstrated and it’s what we had worked with. AAV8 shows a much higher protein expression in non-human primates,” Heier said.
The phase 1 study enrolled patients with neovascular AMD previously treated with at least four anti-VEGF injections over 8 months and who demonstrated a response to therapy.
Three cohorts included six patients receiving 3 × 109 genome copies (GC)/eye, six patients receiving 1 × 1010 GC/eye and six patients receiving 6 ×1010 GC/eye. At 6 months, RGX-314 was well tolerated in all three cohorts with no drug-related adverse events or drug-related serious adverse events recorded, Heier said.
Visual acuity and central retinal thickness were stable in all three cohorts over the 6 months, but three patients in the cohort 3, those receiving the largest dose, demonstrated continued RGX-314 protein expression. Additionally, 50% of patients in that cohort no longer required anti-VEGF injections at 6 months.
“Not only did we see protein expression in month 1 for cohort 3, but when we looked at month 6 we saw that this expression was sustained, actually a little bit higher, but sustained,” Heier said.
A fourth cohort of six patients has been enrolled and will receive 1.6 × 1011 GC/eye; data are expected early in 2019, Heier said. – by Robert Linnehan
Disclosure: Heier reports he receives research support from and is an advisor for Regenxbio.