Initial results from the Phase 1 GARDian1 trial of OCU410ST, recently published in Eye, report early safety and exploratory efficacy findings in adults with Stargardt disease (STGD1).¹

STGD1 is a progressive inherited macular dystrophy caused by biallelic ABCA4 mutations, leading to toxic lipofuscin accumulation in retinal pigment epithelium and gradual loss of central vision.² It typically presents in childhood or adolescence and affects more than 100,000 people across the US and Europe. There are currently no approved therapies to halt or reverse disease progression, leaving a significant unmet medical need for patients and families affected by this condition.

The recent communication in Eye reports results from the first-in-human Phase 1 GARDian1 trial of OCU410ST (AAV5-hRORA), a modifier gene therapy delivered by a single subretinal injection to adults with Stargardt disease.¹ The primary objective of safety and tolerability was met, with no drug-related serious adverse events or adverse events of special interest observed through 12 months. In a predefined subset of six evaluable patients, treated eyes showed slower atrophic lesion growth and a mean improvement in best-corrected visual acuity (~4.5 letters) compared with declines in untreated fellow eyes, with all treated eyes stabilised or improved at 12 months.¹ These exploratory findings and the favourable safety profile support ongoing clinical development, including the Phase 2/3 GARDian3 trial.

Which approaches are shaping Stargardt research?

The landscape of Stargardt disease is progressing, and as of early 2026, several pioneering technologies have entered the clinical stage, moving beyond simple symptom management toward genetic repair and vision restoration.

• Tinlarebant is an oral retinol-binding protein 4 (RBP4) antagonist. In December 2025, positive topline results from the pivotal Phase 3 DRAGON trial in adolescents with Stargardt disease showed a statistically significant reduction in the rate of atrophic lesion growth compared with placebo, supporting planned regulatory submissions.³
• Gildeuretinol (ALK-001) is a deuterated vitamin A analogue designed to reduce toxic bisretinoid formation. In the Phase 2 TEASE-2 study, oral gildeuretinol was well tolerated and demonstrated a reduction in retinal tissue loss in participants with intermediate-stage Stargardt disease.⁴
• SB-007 is a protein splicing therapy that uses a dual-vector system to deliver two halves of the ABCA4 gene, which recombine within retinal cells to form a functional protein. The first patient was treated in the Phase 1/2 ASTRA clinical trial in early 2026.⁵
• ACDN-01 is an RNA-based exon editing therapy designed to correct ABCA4 transcripts at the RNA level rather than replacing the gene. It is currently being evaluated in the early-phase STELLAR clinical trial.⁶
• MCO-010 is an intravitreally delivered optogenetic therapy that uses a light-sensitive opsin to confer photosensitivity to bipolar cells. In the Phase 2 STARLIGHT study, patients with severe Stargardt disease demonstrated clinically meaningful improvements in best-corrected visual acuity, with gains of up to approximately 13 ETDRS letters reported in some participants.⁷
• Cell-based strategies for Stargardt disease are largely focused on early-stage safety and feasibility. Recent review articles detail the promise and challenges of cell-based approaches for Stargardt disease, including stem cell transplantation to replace lost photoreceptors and support retinal structure and function, though long-term efficacy remains under investigation.^8-10

These varied research paths reflect a broad effort to address the root causes of STGD1, slow degeneration, and ultimately preserve or restore vision in affected patients. Continued clinical data will be needed to determine which approaches are safe and effective for routine use.

References:

1. Khanani AM, Vajzovic L, Bakal B. et al. A novel modifier gene therapy to treat Stargardt disease: Phase 1 GARDian1 Trial Insights. Eye. https://doi.org/10.1038/s41433-025-04202-5.
2. Dayma K, Rajanala K, Upadhyay A. Stargardt’s Disease: Molecular Pathogenesis and Current Therapeutic Landscape. Int J Mol Sci. 2025, 26(14), 7006.
3. New Hope for People Living with a Disease Once Deemed Untreatable. Available at: https://investors.belitebio.com/news-releases/news-release-details/new-hope-people-living-disease-once-deemed-untreatable-belite (Accessed 16 January 2026).
4. Alkeus Pharmaceuticals Announces Positive Interim Results Demonstrating No Signs of Disease Progression in Early-Stage Stargardt Disease Patients Treated with Gildeuretinol. Available at: https://alkeuspharma.com/wp-content/uploads/2024/05/alkeus-pharmaceuticals-announces-positive-interim.pdf (Accessed 16 January 2026).
5. Oxford team treats first patient in ground-breaking retinal gene therapy trial. Available at: https://oxfordbrc.nihr.ac.uk/oxford-team-treats-first-patient-in-ground-breaking-retinal-gene-therapy-trial/#:~:text=The%20ASTRA%20trial%20is%20evaluating%20a%20treatment,genetic%20medicines%20company%20pioneering%20protein%20splicing%20to (Accessed 16 January 2026).
6. Study to Evaluate ACDN-01 in ABCA4-related Stargardt Retinopathy (STELLAR). Available at: https://clinicaltrials.gov/study/NCT06467344?term=Ascidian&rank=2 (Accessed 16 January 2026).
7. Lam BL, et al. Safety and efficacy of MCO-010 optogenetic therapy in patients with Stargardt disease in USA (STARLIGHT): an open-label multi-center Ph2 trial. eClinicalMedicine. 2025;87:103430.
8. Kansara S, Shetty R, Narayanan R, et al. Stem cell therapy in Stargardt disease: a systematic review. Int J Mol Sci. 2023;24:318–327.
9. Ghenciu LA, Hațegan OA, Stoicescu ER, Iacob R, Șișu AM. Emerging Therapeutic Approaches and Genetic Insights in Stargardt Disease: A Comprehensive Review. Int J Mol Sci. 2024:14;25:8859.
10. Chen X, Xu N, Li J, Zhao M, Huang L. Stem cell therapy for inherited retinal diseases: a systematic review and meta-analysis. Stem Cell Res Ther. 2023;14:286.

Citation: Novel Phase 1 gene therapy shows safety and early signals in Stargardt disease. touchOPHTHALMOLOGY. 16 January, 2026.

Disclosure: This article was created by the touchOPHTHALMOLOGY team utilizing AI as an editorial tool (ChatGPT (GPT-4o) [Large language model]. https://chat.openai.com/chat.) The content was developed and edited by human editors. No funding was received in the publication of this article.

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