Atsena Therapeutics announced the publication of 12-month safety and efficacy data from its phase 1/2 clinical trial of ATSN-101, a gene therapy for Leber congenital amaurosis (LCA1), in The Lancet. The trial (NCT03920007), which included 15 patients with biallelic mutations in GUCY2D, showed encouraging results, with those receiving high doses experiencing a 100-fold improvement in retinal sensitivity. Improvements in visual function were observed as early as 28 days after treatment and persisted for 12 months.

ATSN-101 is the first gene therapy under investigation for LCA1, a rare inherited retinal disease that causes severe vision impairment or blindness from infancy. Patients were treated at the Scheie Eye Institute, University of Pennsylvania, in Philadelphia, and at the Casey Eye Institute in Portland, Oregon.

In addition to improvements in full-field stimulus test results, modest gains in visual acuity were noted in high-dose patients, along with a high tolerability profile. No serious treatment-related adverse events were reported, and any ocular inflammation was mild and reversible with steroids.

Atsena has received Rare Pediatric Disease designation, Regenerative Medicine Advanced Therapy designation, and Orphan Drug designation from the US Food and Drug Administration for ATSN-101. “The improvements in visual function and tolerability we saw at the high dose of ATSN-101 at 12 months post-treatment … support a future randomized, controlled phase 3 trial to further evaluate this subretinal gene therapy in patients with LCA1,” said Artur Cideciyan, PhD, research professor of ophthalmology at the Scheie Eye Institute and senior author of the paper.