Ascidian Therapeutics has announced the completion of the adult dose escalation portion of the STELLAR phase 1/2 clinical trial of ACDN-01 in Stargardt disease, and expansion of the STELLAR study to pediatric subjects over 12 years of age.

The first-in-human safety data on ACDN-01 from the STELLAR study will be presented at the American Society of Gene & Cell Therapy Annual Meeting on May 12, 2026.

STELLAR is a multi-center, open-label, dose-escalation study evaluating ACDN-01, Ascidian's lead RNA exon editor candidate. The trial assesses the safety and preliminary efficacy of a single subretinal injection in people with Stargardt disease and other ABCA4 retinopathies. The dose escalation portion of the study enrolled 10 adult participants (ages 18-77) and is now enrolling pediatric subjects aged 12 years and older.

To support future clinical development in Stargardt disease, Ascidian has also initiated STARPATH, an observational study for adults and children aged five years and older. Participants receive genetic testing and high-resolution retinal imaging to better characterise their disease and assess eligibility for future ACDN-01 trials.

Michael Ehlers, M.D., Ph.D., Founder, President, and Chief Executive Officer (CEO), Ascidian Therapeutics, said, "ACDN-01 offers a novel, differentiated approach to correcting the genetic basis of Stargardt disease. By targeting RNA, ACDN-01 has the potential to address the root cause of Stargardt disease, using a single AAV vector, without altering DNA or introducing foreign enzymes. Ascidian's goal is to turn pioneering science into life-changing solutions for families living with this blinding condition and today is an important step towards that goal."

ACDN-01, the only clinical-stage, single vector product in development which targets the underlying cause of Stargardt disease, performs in vivo RNA exon editing and restores full-length ABCA4 protein that is deficient in Stargardt disease–without modifying the genome or introducing foreign enzymes. This first-in-class approach has already demonstrated durable and efficient ABCA4 exon editing in both non-human primate and human retinal explant models.

Mark Pennesi, M.D., Ph.D., FARVO, Chief Medical Officer (CMO), Retina Foundation of Dallas and Adjunct Professor of Ophthalmology, Oregon Health and Science University Casey Eye Institute, said, "The Stargardt community has long awaited a therapy that addresses the genetic complexity of this disease. With adult dose escalation complete and pediatric subjects now enrolling, we have the opportunity to evaluate ACDN-01 across a broader range of subjects, including those earlier in their disease, where intervention may have the greatest impact."