Atsena Therapeutics has dosed the first patient in the Phase 3 pivotal cohort of its LIGHTHOUSE trial evaluating ATSN-201, an investigational gene therapy for X-linked retinoschisis (XLRS).

The Durham, North Carolina-based company said enrollment began in May and has already reached 10 percent of the planned study population. Atsena expects to complete enrollment by the end of the first quarter of 2027, with topline results anticipated in the first half of 2028. A Biologics License Application filing is targeted for the second half of 2028.

The pivotal cohort is enrolling 76 adults and children aged six years and older across medical centers in North America and Europe. Patients will be randomized approximately 1:1 to receive ATSN-201 or to enter a control arm, which will be observed for 12 months before participants are offered treatment. The primary endpoint is change in microperimetry at 52 weeks, aligned with both the FDA and European Medicines Agency.

XLRS is a rare inherited retinal disease caused by mutations in the RS1 gene. It primarily affects males, is typically diagnosed in childhood, and can lead to progressive vision loss and blindness. There are currently no approved treatments.

Atsena said Phase 1/2 data showed ATSN-201 could reverse structural retinal damage and improve retinal and visual function, with effects durable through at least one year of follow-up.

CEO of Atsena, Patrick Ritschel, said: "Dosing the first patient in the LIGHTHOUSE pivotal cohort is a defining moment for Atsena and for the XLRS community. The speed with which we are enrolling speaks to the urgency patients and physicians have about finding a treatment for this disease… XLRS families have waited a long time for a treatment, and we intend to deliver one."

Source: Atsena Therapeutics.