April 01, 2026-
Ocugen announced the completion of enrollment and dosing in the Phase 2/3 GARDian3 pivotal clinical trial evaluating OCU410ST, an AAV5-based modifier gene therapy for Stargardt disease (ABCA4-associated retinopathies). The study enrolled 63 patients in less than nine months, marking a significant milestone in the development of a potential first-in-class, one-time treatment for this inherited retinal disorder.
OCU410ST is designed as a mutation-independent modifier gene therapy that delivers the RORA (RAR-Related Orphan Receptor A) gene to the retina using an AAV5 vector. Rather than replacing the defective ABCA4 gene directly, the therapy aims to regulate multiple disease pathways associated with retinal degeneration, including lipofuscin accumulation, oxidative stress, complement activation, inflammation, and photoreceptor survival.
The GARDian3 trial is a multicenter, randomized, masked Phase 2/3 confirmatory study evaluating the efficacy and safety of a single subretinal injection of OCU410ST. Participants in the treatment group received 3 × 10¹⁰ vector genomes per eye, administered to the eye with poorer visual acuity. The trial’s primary endpoint is the reduction in atrophic lesion growth at 12 months, while secondary endpoints include improvements in best-corrected visual acuity (BCVA) and low luminance visual acuity (LLVA). Additional observational measures include preservation of the ellipsoid zone (EZ), a structural marker associated with photoreceptor integrity and visual function.
An interim analysis is planned for Q3 2026, when 24 treated participants complete the eight-month follow-up period. Topline results are expected in the second quarter of 2027, with Ocugen planning to submit a Biologics License Application (BLA) by mid-2027 if results support regulatory filing.
Earlier data from the Phase 1 GARDian1 trial provided encouraging signals of efficacy. After 12 months, treated eyes showed a 54% reduction in atrophic lesion growth compared with untreated fellow eyes, along with stabilization or improvement in visual acuity in all evaluable patients. Treated eyes gained an average of six letters in BCVA, while untreated eyes experienced a decline. Structural analysis also indicated preservation of photoreceptor integrity, with a slower rate of ellipsoid zone loss in treated eyes.
Across clinical studies to date, OCU410ST has demonstrated a favorable safety and tolerability profile, with no reported serious adverse events or adverse events of special interest, including intraocular inflammation or ischemic optic neuropathy.
Stargardt disease is the most common inherited macular degeneration, typically caused by biallelic mutations in the ABCA4 gene. The disease often begins in childhood or adolescence and leads to progressive central vision loss. Approximately 100,000 patients in the United States and Europe are affected, and there are currently no FDA-approved therapies for the condition.
If successful, OCU410ST could represent a mutation-agnostic gene therapy approach for Stargardt disease, offering a potential one-time treatment designed to slow retinal degeneration and preserve visual function.
