FDA Grants Atsena RMAT Designation for Reinoschisis Gene Therapy

Rare Daily Staff

The U.S. Food and Drug Administration granted Atsena Therapeutics’ ATSN-201, an experimental gene therapy to treat the rare eye disease X-linked retinoschisis Regenerative Medicine Advanced Therapy designation.

The designation is a dedicated program designed to expedite the drug development and review processes for promising pipeline products, including gene therapies. A regenerative medicine therapy is eligible for Regenerative Medicine Advanced Therapy (RMAT) designation if it is intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug or therapy has the potential to address unmet medical needs for that disease or condition.

RMAT designation provides sponsors with intensive FDA guidance on efficient drug development. This includes the ability to discuss surrogate or intermediate endpoints, potential ways to support accelerated approval and satisfy post-approval requirements, potential priority review of the biologics license application, and other opportunities to expedite development and review.

X-linked retinoschisis (XLRS) is an X-linked disease caused by mutations in the RS1 gene, which encodes retinoschisin, a protein secreted primarily by photoreceptors. RS1 is localized to the extracellular surface of rods, cones, and bipolar cells. XLRS is characterized by schisis, or abnormal splitting of retinal layers, which causes impaired visual acuity that is not correctable with glasses and leads to progressive vision loss and ultimately blindness. There are currently no approved treatments for XLRS.

ATSN-201 leverages AAV.SPR, the company’s novel spreading capsid, to achieve therapeutic levels of gene expression in photoreceptors of the central retina while avoiding the surgical risks of foveal detachment.

The safety and tolerability of ATSN-201 is currently being evaluated in the LIGHTHOUSE study, a Phase I/II, dose-escalation and dose-expansion clinical trial in male patients ages six and older with a clinical diagnosis of XLRS caused by mutations in the RS1 gene. Enrollment for the study is ongoing.