Key Takeaways

  • Atsena Therapeutics has dosed the first patient in the phase 3 pivotal cohort of the LIGHTHOUSE trial evaluating ATSN-201 for X-linked retinoschisis
  • The 76-patient study will assess microperimetry at 52 weeks as its primary endpoint, with enrollment expected to conclude in the first quarter of 2027
  • ATSN-201 previously demonstrated encouraging structural and functional improvements in phase 1/2 testing, and no approved treatments currently exist for XLRS

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

The clinical-stage gene therapy company reported that enrollment began in May and has already reached approximately 10% of the planned study population. Atsena expects enrollment to continue rapidly as additional trial sites become active across North America and Europe. The company anticipates completing enrollment by the end of the first quarter of 2027. Topline data are expected in the first half of 2028, with a Biologics License Application filing targeted for the second half of that year.

“Brisk enrollment of the study reflects the significant unmet need in XLRS, a disease for which no approved treatments exist, and strong interest from leading clinicians and patients who have been following ATSN-201's clinical progress,” said Kenji Fujita, MD, chief medical officer of Atsena, in a company statement.

According to Fujita, early clinical findings from the phase 1/2 portion of the LIGHTHOUSE study demonstrated closure of schisis cavities and improvements in retinal and visual function in a majority of treated patients. The company reported that these outcomes have remained durable through at least one year of follow-up.

LIGHTHOUSE Phase 3 Design

The pivotal portion of the LIGHTHOUSE trial is expected to enroll 76 patients with XLRS, including adults and children as young as 6 years of age, at clinical centers throughout North America and Europe. Participants are being randomized approximately 1:1 to either receive ATSN-201 or enter an observation control arm. Patients assigned to the control group will be observed for 12 months before being offered the option to receive treatment.

The study's primary endpoint is change in microperimetry at 52 weeks, an outcome measure selected in alignment with both the FDA and the European Medicines Agency (EMA). Secondary endpoints include assessments of visual acuity and retinal structure using optical coherence tomography.