Atsena's ATSN-201 shows durable XLRS benefit at 18 months

Atsena Therapeutics has presented 18-month data from Part A of its Phase 1/2/3 LIGHTHOUSE trial, reporting that ATSN-201, its investigational gene therapy for X-linked retinoschisis (XLRS), continued to show durable structural and functional benefits with no drug-related serious adverse events across the nine adult patients evaluated.

The results were disclosed at the American Academy of Optometry 2026 Annual Meeting in Anaheim, California, where the abstract was selected for the Academy's Innovations in Vision and Eye Care press conference, a competitive slot that reflects growing clinical interest in inherited retinal disease.

What the data show

Seven of nine treated eyes maintained foveal schisis closure at 18 months, a structural improvement not observed in untreated fellow eyes. Treated eyes also recorded statistically significant gains in central retinal thickness, microperimetry, best-corrected visual acuity (BCVA) and low-luminance visual acuity (LLVA). Six of the nine treated eyes achieved at least a 7 dB improvement in microperimetry, meeting the responder threshold that anchors the primary endpoint in the ongoing pivotal Phase 3 Part C cohort. Seven of nine showed visual acuity gains of ten letters or more on BCVA or LLVA, compared with one of nine untreated eyes.

Kenji Fujita, Chief Medical Officer of Atsena, said the results "reinforce ATSN-201's ability to deliver durable structural and functional improvements," adding that the safety profile and ongoing pivotal enrolment keep the company on track for a Biologics License Application filing in the second half of 2028.

Part A tested three dose levels of ATSN-201 administered by subretinal injection in adult patients. The therapy uses Atsena's proprietary AAV.SPR capsid, which is designed to spread laterally from the injection site to transduce the central retina without requiring surgical detachment of the fovea, a procedure that carries meaningful operative risk.

Regulatory path and competitive context

ATSN-201 holds Regenerative Medicine Advanced Therapy, Fast Track, Rare Pediatric Disease and Orphan Drug designations from the FDA, as well as Orphan Designation from the European Medicines Agency. That constellation of designations accelerates review timelines and, in the case of Rare Pediatric Disease designation, creates eligibility for a priority review voucher on BLA approval, a commercially valuable asset that has traded at prices exceeding $100 million in recent years, though valuations vary.

XLRS affects approximately 30,000 males in North America and Europe. No approved disease-specific treatments currently exist, making this a genuine area of unmet need. The competitive landscape for XLRS gene therapy is relatively early-stage: several academic groups and smaller biotechs have explored RS1-directed approaches, but Atsena is the furthest into pivotal development based on publicly available information.

Enrolment in Part C, the randomised controlled Phase 3 cohort of 76 patients aged five and older, is described as running ahead of expectations. Enrolment is due to complete by the end of the first quarter of 2027, with topline readout anticipated in the first half of 2028. The BLA filing window of the second half of 2028 implies a potential FDA decision in 2029 or early 2030, depending on review category. Investors will watch for the full Phase 3 dataset, including the microperimetry primary endpoint and durability of visual acuity gains in a paediatric-inclusive population.

Atsena's broader pipeline includes ATSN-101 for Leber congenital amaurosis type 1, developed in collaboration with Nippon Shinyaku, for which a pivotal Phase 3 is expected to begin shortly.