Atsena Therapeutics Reports Promising Interim Results for Gene Therapy Targeting X-linked Retinoschisis (XLRS)

Atsena Therapeutics has shared encouraging interim data from Part A of its phase 1/2 LIGHTHOUSE clinical trial evaluating ATSN-201, a gene therapy candidate for the treatment of X-linked retinoschisis (XLRS). The findings underscore the potential of Atsena’s proprietary gene delivery platform and highlight favorable safety outcomes alongside compelling efficacy signals in adult patients.

About ATSN-201 and AAV.SPR Technology

ATSN-201 is the company’s lead investigational gene therapy product and utilizes AAV.SPR—a novel spreading capsid designed to deliver therapeutic genes to the photoreceptors in the central retina without detaching the fovea. This approach mitigates a major risk associated with traditional retinal surgeries.

The U.S. Food and Drug Administration (FDA) has recognized ATSN-201 with several designations, including:

       • Regenerative Medicine Advanced Therapy (RMAT)

       •  Fast Track

       •  Rare Pediatric Disease

       • Orphan Drug

Key Findings from Part A of the LIGHTHOUSE Trial

In Part A of the LIGHTHOUSE study, nine adult males with XLRS received subretinal injections of ATSN-201 across escalating dose levels. The treatment was well tolerated, with no dose-limiting toxicities or therapy-related serious adverse events reported. Most adverse events were mild (Grade 1–2) and related to the surgical procedure itself. One unrelated serious adverse event—a fever of unknown origin—was reported but did not lead to study withdrawal.

Notable Efficacy Outcomes:

       • Foveal schisis closure observed in 7 out of 9 treated eyes, not seen in untreated eyes

       • 67% of treated eyes (6 of 9) showed ≥7 dB improvement in microperimetry in the least sensitive loci

       • Statistically significant improvements in both Best Corrected Visual Acuity (BCVA) and Low Luminance Visual Acuity (LLVA)

       • Strong correlation between anatomical improvements and functional vision gains

Dr. Kenji Fujita, Chief Medical Officer at Atsena Therapeutics, stated:

“The full Part A data reinforce the favorable safety profile and demonstrate encouraging structural and functional benefits across all three dose levels of ATSN-201. The foveal schisis closure seen in 7 of 9 treated patients is particularly exciting—it validates the potential of our AAV.SPR capsid to spread laterally and safely deliver gene therapy to the central retina.”

These results were presented at the 2025 Association for Research in Vision and Ophthalmology (ARVO) and American Society for Gene and Cell Therapy (ASGCT) annual meetings.

Next Steps: Part B of LIGHTHOUSE Trial

With Part A complete, enrollment is now underway for Part B. This phase will include:

       • Nine additional adult participants divided into three arms: low volume, high volume, and control (deferred treatment)

       • Three pediatric patients, to be treated after a safety review of adult data

As in Part A, Part B will evaluate safety, macular structure, microperimetry, and visual acuity outcomes.