Atsena Therapeutics has reported evidence of efficacy in a clinical trial of an eye disease gene therapy, encouraging the biotech to forge ahead with a study that could support a filing for approval in 2028.
The data, which Atsena is sharing this week at the American Academy of Ophthalmology Annual Meeting, come from the first two parts of the phase 1/2/3 Lighthouse clinical trial. Across the first two parts, Atsena administered different doses and volumes of a gene therapy, ATSN-201, into one eye in 18 X-linked retinoschisis (XLRS) patients. Another three patients formed an untreated control arm.
Half of the 18 patients met the microperimetry response criteria. Microperimetry, which assesses retinal sensitivity, is the primary endpoint in the phase 3 part of the Lighthouse study. One of the 18 patients had a microperimetry response in their untreated eye.
Six of the nine patients who received the phase 3 dose responded, compared with none of the three control patients. Atsena chose the lowest dose for the phase 3 part of the trial, reflecting its consistent efficacy profile and more favorable tolerability profile relative to higher doses.
Eight of the nine patients on the phase 3 dose had baseline visual acuity worse than 20/40, the threshold commonly required for driving eligibility in the U.S. Three patients had visual acuity of 20/40 or better as of the latest assessments. Another three people had improved visual acuity, while visual acuity was unchanged in the other two patients.
In the full, 18-patient analysis, 12 people met the optical coherence tomography (OCT) response criteria and nine were visual acuity responders. The figures include five OCT responders in the subpopulation of patients who received the phase 3 dose. OCT is a noninvasive imaging test.
Atsena, which shared safety data last year, expects to complete enrollment in the third part of the study in the first quarter of next year. The timeline puts the biotech on track to report data in the first half of 2028 and file for FDA approval by the end of that year.
Phase 3 success would represent a win for Bain Capital, which led Atsena’s $150 million series C round last year, and for patients with an eye disease that lacks approved, disease-specific treatments. XLRS affects about 30,000 men in North America and Europe. Multiple groups have studied possible therapies without delivering a treatment for the rare eye disease.