Atsena Therapeutics Completes Adult Dosing in LIGHTHOUSE Gene Therapy Trial for X-Linked Retinoschisis
Atsena Therapeutics announced the completion of adult patient dosing in Part B of the LIGHTHOUSE study, the company’s phase 1/2/3 clinical trial evaluating ATSN-201 for the treatment of X-linked retinoschisis (XLRS). Pending approval from the Data Monitoring Committee, pediatric dosing is expected to begin in Q4 2025.
“Dosing of adult patients in all groups of Part B is now complete, and follow-up is ongoing,” said Kenji Fujita, MD, Chief Medical Officer of Atsena Therapeutics. “Preliminary safety data remain favorable, and early structural and functional readouts, including improvements in foveal schisis and retinal sensitivity, are consistent with the positive signals observed in Part A. These findings will enable initiation of pediatric dosing, a critical next step in assessing the full therapeutic potential of ATSN-201 across the XLRS patient population.”
Part B of the multicenter trial includes nine adult and three pediatric participants. Adult subjects are divided into low-volume, high-volume, and control groups; control patients will be observed off-therapy for 1 year before becoming eligible for treatment. In July 2025, the FDA agreed to expand the LIGHTHOUSE study to serve as a pivotal trial supporting a Biologics License Application (BLA) anticipated in early 2028.
“Completing adult dosing in Part B of the LIGHTHOUSE study represents a meaningful milestone as we advance ATSN-201 through the pivotal trial pathway,” said Patrick Ritschel, MBA, Chief Executive Officer of Atsena Therapeutics. “The FDA’s alignment on our trial design underscores the growing momentum behind this program. With no approved therapies, we remain committed to progressing this potential first- and best-in-class gene therapy as rapidly and rigorously as possible to patients with XLRS.”
ATSN-201 is an investigational gene therapy that employs AAV.SPR, a novel laterally spreading capsid designed to efficiently target photoreceptors in the central retina while avoiding the surgical risks of foveal detachment. The Phase 1/2/3 LIGHTHOUSE Trial (ClinicalTrials.gov Identifier: NCT05878860) consists of three parts:
Part A – early-phase adult cohorts (1–3)
Part B – current adult and pediatric cohorts (4–5)
Part C – pivotal Phase III cohort (6)
ATSN-201 is the first gene therapy for XLRS to demonstrate both efficacy and positive safety data in a phase 1/2 trial, according to Atsena. Most treated patients have shown meaningful improvements in foveal schisis closure, retinal sensitivity, and visual function (microperimetry, best-corrected visual acuity, and low-luminance visual acuity). The therapy has been well tolerated for at least 1 year post-treatment, with no serious adverse events reported.
Regulatory designations for ATSN-201 include Regenerative Medicine Advanced Therapy (RMAT), Fast Track, Rare Pediatric Disease, and Orphan Drug status from the FDA.