Atsena Therapeutics Begins Phase I/II Trial Part B for Gene Therapy ATSN-201 in X-linked Retinoschisis

Atsena Therapeutics, a company in the clinical stage of developing gene therapy solutions aimed at reversing or preventing blindness, has announced the launch of Part B of its LIGHTHOUSE study. This Phase I/II clinical trial is focused on evaluating ATSN-201, a cutting-edge gene therapy candidate, for treating X-linked retinoschisis (XLRS). ATSN-201 utilizes AAV.SPR, a novel capsid designed by Atsena, which enables the spread of therapeutic levels of gene expression across the central retina's photoreceptors without the risks associated with detaching the fovea during surgery.

The commencement of Part B follows the successful completion of Part A, which involved enrolling and dosing participants. The earlier phase showed positive functional and structural outcomes, validating the novel AAV.SPR capsid technology. Patrick Ritschel, Atsena Therapeutics' CEO, emphasized the importance of including both adult and pediatric participants in Part B, noting the designation of ATSN-201 as a Rare Pediatric Disease treatment. He reiterated the company's commitment to advancing a therapeutic option that addresses the unmet needs of patients with XLRS.

Part A of the study investigated the safety and tolerability of three different doses of ATSN-201 via subretinal injection. Following a review of initial safety data, the Data Monitoring Committee has endorsed moving forward with Part B using a concentration of 1.0E11 vg/mL. This dosage was determined to offer the best balance between tolerability and efficacy based on preliminary clinical results. Part B will be a multicenter trial involving nine additional adult participants and three pediatric patients diagnosed with XLRS. The adult group will be divided into three treatment arms: low volume, high volume, and control. Those in the control group will be monitored without therapy for one year, after which they will have the option to receive treatment. The pediatric group will be treated after assessing preliminary results from the adult participants. This phase aims to continue evaluating the safety and effectiveness of ATSN-201, focusing on aspects like microperimetry, visual acuity, and macular structure.

Kenji Fujita, MD, Chief Medical Officer of Atsena, highlighted a significant advantage of ATSN-201: its application does not require precise subretinal placement under a specific retinal area. This flexibility allows surgeons greater discretion in bleb placement and safe delivery of the healthy gene to crucial parts of the retina. By experimenting with different administration volumes in Part B, the study aims to determine the optimal way to achieve the widest therapeutic impact.

Currently, there are no approved treatments available for XLRS, a condition usually identified in early childhood that predominantly affects males. Characterized by schisis, or the abnormal splitting of retinal layers, XLRS results in impaired visual acuity that cannot be corrected with glasses and can eventually lead to blindness. Approximately 30,000 males in the U.S. and the EU are affected by this inherited retinal disorder.

The LIGHTHOUSE study is an open-label, dose-escalation and dose-expansion trial that continues to assess the safety and tolerability of ATSN-201 in male patients six years and older with a clinical diagnosis of XLRS caused by mutations in the RS1 gene. Enrollment for the study is ongoing, and ATSN-201 has been designated as an Orphan Drug and Rare Pediatric Disease treatment by the U.S. Food and Drug Administration.

Atsena Therapeutics is at the forefront of developing gene therapies for inherited retinal diseases. The company's pipeline is driven by novel adeno-associated virus (AAV) technology, designed to overcome challenges posed by such diseases. Founded by leaders in ocular gene therapy, Atsena is committed to addressing the needs of patients experiencing vision loss.