X-Linked Retinoschisis (XLRS) is an inherited retinal condition that causes abnormal splitting of the retinal layers. The condition is caused by mutations in the RS1 gene and is the leading cause of macular degeneration in males. Affected boys often develop poor vision by the time they start school, and typically have best-corrected visual acuity of 20/60 to 20/120 at initial diagnosis. During teenage years, the individual’s ability to see worsens, making simple activities such as reading, driving, and even recognizing a loved one in a crowd very difficult.
Furthermore, XLRS can lead to vitreous hemorrhage or retinal detachment in up to 40% of patients. These events can happen at any time and detrimentally affect vision. Over time, XLRS can ultimately result in legal blindness.
AGTC is developing an AAV gene therapy product candidate expressing the RS1 protein for the treatment of XLRS. In animal models of XLRS, treatment with an AAV vector expressing the RS1 protein has resulted in long-term improvement in retinal function and restoration of retinal structure. Based on the preclinical proof-of-concept results, AGTC is currently conducting a Phase 1/2 clinical trial to evaluate the safety and efficacy of the AAV gene therapy product candidate in patients with XLRS.