The ABO-503 gene therapy for X-linked retinoschisis (XLRS) has been selected to participate in the U.S. Food and Drug Administration's (FDA) Rare Disease Endpoint Advancement (RDEA) Pilot Program, as announced by Abeona Therapeutics Inc., a commercial-stage biopharmaceutical company focusing on cell and gene therapies.

This prestigious program, which accepts only up to three proposals annually between 2023 and 2027, is designed to accelerate the development and timely approval of rare disease therapies by supporting the creation and validation of novel efficacy endpoints for use in clinical trials.

XLRS is a severe, rare monogenic retinal disease caused by mutations in the RS1 gene, leading to the irreversible loss of photoreceptor cells and visual impairment, affecting up to an estimated 35,000 males across the U.S. and Europe, with no currently approved disease-modifying therapies.

Abeona's participation in the RDEA program grants the company enhanced communication and collaboration with the FDA, including frequent advice and regular ad-hoc conversations focused on accelerating the development and validation of product-specific novel efficacy endpoints for ABO-503. The company’s CEO, Vish Seshadri, noted that this selection will meaningfully improve the success rate of the XLRS clinical development efforts and could broadly facilitate innovation across other inherited retinal diseases by establishing new endpoint standards. ABO-503 itself is composed of a functional human RS1 gene packaged within the novel AIM capsid AAV204. Preclinical studies have shown promising results in a mouse model of XLRS, demonstrating structural and functional improvements such as enhanced cone photoreceptor density, restoration of outer retina architecture by eliminating characteristic cysts, and improvements in visual function confirmed by electroretinogram (ERG). Abeona anticipates completing IND-enabling studies for ABO-503 in the second half of 2026. The company is already a commercial-stage entity, known for ZEVASKYN for recessive dystrophic epidermolysis bullosa (RDEB), and is leveraging its fully integrated manufacturing facility and next-generation AAV capsids in its development pipeline.