Atsena – Programs – Leber Congenital Amaurosis 1

ATSENA is evaluating ATSN-201, our first- and best-in-class gene therapy candidate for X-linked retinoschisis (XLRS), in the LIGHTHOUSE trial (ClinicalTrials.gov Identifier: NCT05878860). ATSN-201 leverages AAV.SPR, our novel laterally spreading capsid, which is designed to enable safe and efficient gene delivery to the central retina by spreading beyond the margins of the subretinal injection site without the need for surgical foveal detachment. ATSN-201 is the first XLRS gene therapy to demonstrate reversal of structural damage to the retina and improvements in visual function in a clinical trial.

Disease Background

XLRS is a monogenic X-linked disease caused by mutations in the RS1 gene, which encodes retinoschisin, a protein secreted primarily by photoreceptors. XLRS is characterized by schisis, or abnormal splitting of retinal layers, which causes impaired visual acuity that is not correctable with glasses and leads to progressive vision loss and ultimately blindness. XLRS primarily affects males and is typically diagnosed in early childhood. Approximately 30,000 males in the U.S. and EU have XLRS, for which there are currently no approved treatments.

Clinical Development

The LIGHTHOUSE trial is a Phase 1/2/3 clinical trial evaluating ATSN-201 in patients ages six and older with a clinical diagnosis of XLRS. The Phase 1/2 portion of the trial demonstrated a favorable safety profile across all dose levels, with no serious adverse events related to treatment reported. The majority of patients demonstrated improvements in retinal structure, including foveal schisis closure, as well as meaningful improvements in visual function as measured by microperimetry and visual acuity. ATSN-201 is being evaluated in the pivotal Phase 3 portion of the LIGHTHOUSE trial.

FDA Designations

Atsena has received four FDA designations for ATSN-201:

Regenerative Medicine Advanced Therapy (RMAT)

Fast Track

Rare Pediatric Disease (RPD), and

Orphan Drug Designation (ODD).

Atsena presented 12-month results from Part A of the Phase 1/2/3 gene therapy clinical trial for X-linked retinoschisis at the Association for research in Vision and Ophthalmology Annual Meeting in May 2026.

View the presentation here.