Biotechnology company REGENXBIO Inc (Nasdaq:RGNX) on Thursday announced positive long-term follow-up data from the Phase II ALTITUDE study of investigational surabgene lomparvovec (sura-vec, ABBV-RGX-314) in diabetic retinopathy (DR) using suprachoroidal delivery.

REGENXBIO presented the new data at the Retina Society's 59th Annual Scientific Meeting in Los Angeles.

Sura-vec is a one-time investigational gene therapy designed to deliver sustained treatment effect in wet AMD, diabetic retinopathy and other chronic retinal conditions. Sura-vec uses the NAV-AAV8 vector to encode an antibody fragment designed to inhibit vascular endothelial growth factor (VEGF). The sura-vec transgene protein inhibits the VEGF pathway by which new, leaky blood vessels grow and contribute to the accumulation of fluid in the retina.

In long-term follow-up from the Phase II ALTITUDE trial, a single in-office administration of sura-vec using suprachoroidal delivery in participants with non-proliferative DR (NPDR) at Dose Level 3 with short-course prophylactic topical steroids demonstrated a durable efficacy profile at three years with no new sura-vec-related safety signals observed during long-term follow up.

Results showed that 60% of all Dose Level 3 participants with three-year visits achieved a greater than 2-step improvement on the Diabetic Retinopathy Severity Scale (DRSS) without additional treatment for diabetic retinopathy. These participants did not experience any vision-threatening events. Additionally, the majority of participants who achieved a 1-step DRSS improvement at one year without supplemental anti-VEGF injections went on to achieve a greater than 2-step DRSS improvement by three years without additional treatment for diabetic retinopathy.

There were no new sura-vec-related safety signals and no intraocular inflammation observed through three years with short-course prophylactic topical steroids.

According to REGENEXBIO, these data are consistent with previously presented two and a half-year Dose Level 3 NPDR data from the ALTITUDE trial and support the potential of one-time in-office sura-vec to modify the underlying disease and decrease risk of vision-threatening events. Dose Level 3 is being evaluated in the Phase IIb/III NAAVIGATE trial of sura-vec in NPDR.