DURHAM, N.C. — October 7, 2026
Atsena Therapeutics announced preliminary safety and efficacy results from Parts A and B of the Phase 1/2/3 LIGHTHOUSE trial evaluating investigational gene therapy ATSN-201 in patients with X-linked retinoschisis (XLRS). The company reported structural and functional improvements across treated patients, including microperimetry responses at the pivotal dose and evidence of sustained benefit following a single administration. ATSN-201 demonstrated a favorable safety profile, with no drug-related serious adverse events or dose-limiting toxicities reported. Atsena is advancing the program into the pivotal Part C portion of the study, with enrollment expected to complete in the first quarter of 2027.
Pivotal Dose Demonstrates Visual Function Improvements
Among nine patients treated at the selected pivotal dose, seven of nine demonstrated a response on at least one visual function measure, including microperimetry and visual acuity. Five of nine patients were responders based on optical coherence tomography (OCT), six of nine met the microperimetry response definition and three of nine demonstrated a visual acuity response. No untreated fellow eyes met responder criteria across OCT, microperimetry or visual acuity. Across all 18 treated patients in Parts A and B, 13 demonstrated a response on at least one visual function measure. Atsena said the pivotal dose of 1.1E10 vg/eye was selected for further development based on consistent efficacy together with more favorable tolerability compared with higher doses.
Three Patients Reach 20/40 Vision After Treatment
Newly reported data also showed potentially meaningful visual improvements among patients treated at the pivotal dose. Of eight patients who had baseline visual acuity worse than 20/40, three had reached 20/40 or better at their latest assessment, a level commonly associated with driving eligibility in the United States. The earliest-treated patient reached three years of follow-up in July 2026 and continued to show structural and functional benefit. At 36 months, foveal schisis remained closed, while the patient demonstrated improvements of +12 dB in microperimetry, +19 letters in best-corrected visual acuity and +22 letters in low-luminance visual acuity. Atsena said the durability data support continued evaluation of ATSN-201 in the pivotal study.
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LIGHTHOUSE Phase 3 Enrollment Advances Toward 2027
Part C of the LIGHTHOUSE trial is a randomized, controlled Phase 3 study expected to enroll 76 patients aged five years and older, with microperimetry as the primary endpoint and a 52-week primary readout. Enrollment began in June 2026 and is progressing ahead of expectations, according to Atsena. The company expects enrollment to complete by the end of the first quarter of 2027, with topline results anticipated in the first half of 2028 and a potential BLA filing targeted for the second half of 2028. ATSN-201 uses Atsena’s AAV.SPR capsid, designed to laterally spread from the injection site and target photoreceptors in the central retina. ATSN-201 remains investigational, and its safety and efficacy have not been established by the FDA or other regulatory authorities.
Source::Atsena Therapeutics, press release
