Atsena Therapeutics has reported positive interim six-month results from Part B of its Phase 1/2/3 LIGHTHOUSE trial evaluating ATSN-201, an investigational gene therapy for X-linked retinoschisis (XLRS).
The data, presented at the Foundation Fighting Blindness Retinal Therapeutics Innovation Summit in Denver, Colorado, showed structural and functional improvements in adults, alongside a favorable safety profile. Early safety findings in pediatric patients were also consistent with adult cohorts, the company said.
XLRS is an inherited retinal disease caused by mutations in the RS1 gene. It primarily affects males, is often diagnosed in childhood, and causes abnormal splitting of the retinal layers, leading to impaired visual acuity and progressive vision loss. Around 30,000 males in the US and EU are estimated to have XLRS, and there are currently no approved treatments.
Part B of LIGHTHOUSE is evaluating nine adults and three pediatric patients. The adult group includes two treatment arms testing different injection volumes, as well as an untreated control arm. Control patients may receive treatment after one year of observation.
At six months, foveal schisis closure was confirmed in four of six treated adults in Cohort 4. No foveal schisis closure was seen in untreated control subjects or untreated contralateral eyes. Atsena also reported that microperimetry responses in Part B closely mirrored those observed at the same time point in Part A of the study.
No serious adverse events were reported across Part B cohorts. There were no cases of macular hole formation, retinal detachment, or treatment discontinuation. Subretinal deposits seen in a subset of adult subjects resolved with transient steroid treatment. Pediatric patients aged 8–12 also showed a clean early safety profile, with no serious adverse events or retinal complications.
“ATSN-201 is the first gene therapy to advance to a registrational trial for XLRS, a disease with no approved treatments,” said Chief Medical Officer of Atsena, Kenji Fujita.
Enrollment is now underway in Part C, the pivotal Phase 3 portion of LIGHTHOUSE, which will include 76 patients across sites in North America and Europe. The primary endpoint is microperimetry at 52 weeks, aligned with the FDA and European Medicines Agency (EMA), with visual acuity and OCT as key secondary endpoints.
Atsena expects enrollment to complete by the end of Q1 2027 and is targeting a Biologics License Application filing in 2028.
Source: FirstWord Pharma.
