Hot on the heels of a $150 million fundraise, Atsena Therapeutics is back with early-stage data for the company’s eye disease gene therapy. The candidate improved the structure and function of the retina and wasn't tied to any serious treatment-related adverse events.
The data come from nine patients with X-linked retinoschisis (XLRS) in the first part of the phase 1/2 Lighthouse trial. The patients were split evenly into three cohorts: a low, middle and high volume group. Each patient received the therapy in one of their eyes.
The findings were presented (PDF) at the annual meeting of the American Society of Cell & Gene Therapy in New Orleans.
No serious adverse events were related to the therapy, called ATSN-201, Atsena said in a May 19 release. Most adverse events were low in severity and related to the subretinal injection used to administer the treatment, according to Atsena.
One patient developed a serious adverse event—a fever of an unknown origin—that was unrelated to both the investigational treatment and its administration, the biotech said. No patients discontinued from the trial and no dose-limiting toxicities were observed.
ATSN-201 uses Atsena’s AAV.SPR virus capsid, which is designed to spread outward from the injection site to reach the entire retina. The gene therapy is made to deliver functional copies of the retinoschisin gene to the retina to treat XLRS. Without retinoschisin, patients with XLRS have retinas that split into separate layers, causing degraded vision that worsens over time. Patients are also at a heightened risk of retinal detachment, a serious injury that can cause blindness if not treated quickly enough.
For seven of nine patients, the splits in their foveas closed in the eye treated with ATSN-201, with statistically significant improvements in visual acuity also recorded, according to Atsena.
The data “reinforce the favorable safety profile and demonstrate encouraging structural and functional benefits across all three dose levels of ATSN-201,” Atsena’s Chief Medical Officer, Kenji Fujita, M.D., said in the release. “We’re particularly pleased that the foveal schisis closure seen in seven of nine patients validates AAV.SPR’s ability to spread laterally beyond the subretinal injection blebs and enable safe gene delivery to the central retina.”
The second phase of Atsena's trial is already underway, with plans to enroll a further nine adult patients and three children. The biotech's gene therapy for the inherited disease has received fast track, rare pediatric disease and orphan drug designations from the FDA.
There are currently no approved treatments for XLRS, which typically emerges in childhood and primarily affects boys.
North Carolina-based Atsena secured a $150 million series C in early April to fund ATSN-201’s clinical development. The company is also progressing a gene therapy for the severe retinal disease Leber congenital amaurosis type 1 through a phase 1/2 trial and touts a preclinical program targeting MYO7A-associated Usher syndrome.
Atsena’s recent fundraise comes at a time when many other gene therapy companies are struggling. About 31% of all biotech layoffs in the first quarter of 2025 came from cell and gene therapy companies.