Atsena Therapeutics has developed ATSN-201, a gene therapy targeting X-linked retinoschisis (XLRS), utilizing a novel AAV.SPR capsid designed for efficient photoreceptor targeting and lateral spread within the retina.

The FDA has approved expanding the LIGHTHOUSE trial of ATSN-201 into a continuous Phase 1/2/3 study, supporting a potential Biologics License Application (BLA) by early 2028, which could accelerate market entry by at least 1.5 years.

This expansion allows the trial to serve as a pivotal study, with positive safety and efficacy data from early phases, including statistically significant improvements in visual acuity and retinal structure.

Recent data from May 2025 indicate that ATSN-201 was well-tolerated and safe, with promising results in improving visual function, leading to the FDA's approval for trial expansion.

ATSN-201 is delivered via subretinal injection and employs the AAV.SPR capsid, which facilitates lateral spread to photoreceptors, addressing the underlying mutation in XLRS.

The therapy has demonstrated a favorable safety profile and efficacy in early clinical trials, with positive results from Part A of the LIGHTHOUSE study showing improvements in retinal structure and visual function.

The ongoing trial's expansion includes a new cohort of approximately 30 patients, with enrollment beginning in Q1 2026 and pivotal data expected in the second half of 2027.

Enrollment of pediatric patients in Part B is expected to start in fall 2025, with a Phase III cohort beginning early 2026, aiming to assess measures like microperimetry, visual acuity, and macular structure.

XLRS is a genetic disorder affecting about 30,000 males in the U.S. and EU, characterized by progressive vision loss due to splitting of retinal layers, with no current approved treatments.

Atsena's pipeline also includes ATSN-101 for Leber congenital amaurosis type 1, which has completed Phase 1/2 trials and is progressing toward pivotal studies.

ATSN-201 has received multiple FDA designations, including RMAT, Fast Track, Orphan Drug, and Rare Pediatric Disease, underscoring its potential as a first-in-class therapy.

The development of ATSN-201 leverages Atsena's innovative AAV.SPR vector, which enables safe transduction of the central retina without surgical detachment, and has shown promising preclinical results.