Single Gene Therapy Dose Holds Diabetic Retinopathy at Bay for Three Years

Diabetic retinopathy is one of the most common complications of long-standing diabetes and a major driver of vision loss in adults worldwide. Existing standard-of-care treatments — repeated intravitreal injections of anti-VEGF drugs — are effective but demanding, requiring visits every four to twelve weeks indefinitely. A gene therapy that works from a single dose could transform how this age-related complication is managed.

Regenxbio presented three-year follow-up data for Surabgene (lomparvovec) at the Retina Society's 59th Annual Scientific Meeting. The therapy uses an AAV vector delivered via a suprachoroidal injection performed in a standard office setting, targeting the underlying vascular dysfunction driving non-proliferative diabetic retinopathy. At the optimal dose level (1.0×10^12 genome copies per eye), 60% of participants with three-year visit data — six of ten — achieved more than a two-step improvement on the Diabetic Retinopathy Severity Scale with no additional treatment required.

Critically, no intraocular inflammation was recorded through three years in all 17 patients at that dose level, even with only a short course of prophylactic topical steroids. This safety profile is notable because inflammation has historically been a limiting concern for ocular gene therapy. The results align with earlier two-and-a-half-year data, suggesting the benefit is stable rather than fading.

For aging adults with diabetes, preserving vision is directly tied to independence, fall risk, and quality of life. A durable single-dose option could meaningfully reduce the healthcare burden while protecting a key functional sense that underpins physical capability and cognitive engagement.

Important caveats apply: the Phase II dataset is small, the three-year cohort covers only ten participants, and longer-term durability beyond three years is unknown. The ongoing Phase IIb/III NAAVIGATE trial will provide the statistical power needed to confirm efficacy and safety at scale before any regulatory submission.