Abeona Therapeutics’ ABO-503 Gene Therapy For X-linked Retinoschisis Selected By FDA For Rare Disease Endpoint Advancement (RDEA) Pilot Program
Abeona’s ABO-503 gene therapy for XLRS selected for FDA’s Rare Disease Endpoint Advancement Pilot Program.
Breaking News
Oct 14, 2025
Simantini Singh Deo

Abeona Therapeutics Inc., a commercial-stage biopharmaceutical company developing cell and gene therapies for serious diseases, has announced that its investigational gene therapy ABO-503 for X-linked retinoschisis (XLRS) has been selected to participate in the U.S. Food and Drug Administration (FDA) Rare Disease Endpoint Advancement (RDEA) Pilot Program.
The RDEA program is designed to accelerate the development and approval of therapies for rare diseases by encouraging the use of novel efficacy endpoints in clinical trials. Participation in this program will allow Abeona to engage in enhanced communication and collaboration with the FDA, including frequent guidance and discussions aimed at supporting the development and validation of new efficacy endpoints for its XLRS program.
“XLRS remains an area of significant unmet medical need,” said Vish Seshadri, Chief Executive Officer of Abeona Therapeutics. “We are honored that our ABO-503 gene therapy has been selected for the FDA’s highly competitive RDEA pilot program. This recognition underscores the potential of our approach and provides an opportunity to accelerate our clinical development efforts. Beyond XLRS, we believe our work under this program may also help advance innovation across our pipeline by establishing new efficacy endpoints that could benefit patients with other inherited retinal diseases.”
ABO-503 is a gene therapy candidate composed of a functional human RS1 gene delivered using Abeona’s proprietary AIM™ capsid AAV204. Preclinical studies have demonstrated that ABO-503 effectively delivers the RS1 gene to the retina in mouse models of XLRS, leading to improvements in retinal structure and function. These studies have shown enhanced cone photoreceptor density, improved photoreceptor cell survival, restoration of normal retinal architecture by eliminating cystic lesions characteristic of XLRS, and functional vision improvements measured through electroretinogram (ERG) testing. Abeona expects to complete Investigational New Drug (IND)-enabling studies for ABO-503 in the second half of 2026.
The FDA’s RDEA Pilot Program, launched to advance the use of novel clinical endpoints for rare disease drug development, accepts a limited number of proposals between 2023 and 2027 — up to one per quarter and a maximum of three per year. Companies applying for the program must demonstrate the novelty and potential impact of their proposed endpoint, along with data supporting its ability to provide substantial evidence of treatment effectiveness. Selection into this program represents a significant step forward for Abeona Therapeutics as it continues its mission to develop transformative gene therapies for patients with rare and serious inherited diseases.