FDA grants RMAT designation to Atsena Therapeutics' gene therapy for XLRS

Atsena Therapeutics announced the FDA approval of its gene therapy product candidate, ATSN-201, the regenerative medicine advanced therapy (RMAT) designation to treat X-linked retinoschisis (XLRS), for which there currently are no approved treatments.¹

This announcement heralds the fourth FDA designation for ATSN-201, which previously received fast track, rare pediatric disease, and orphan drug designations, according to the press release. In the previous week, the company also announced the successful close of an oversubscribed $150 million Series C financing, the proceeds of which will be used to finance ATSN-201.

XLRS, which affects mostly male individuals and is diagnosed in early childhood, is a rare inherited monogenic X-linked disorder caused by mutations in the RS1 gene that encodes retinoschisin, a protein secreted primarily by photoreceptors. XLRS is characterized by retinal schisis, which causes impaired visual acuity uncorrectable by glasses and leads to progressive vision loss and ultimately blindness.

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

Patrick Ritschel, chief executive officer of Atsena Therapeutics, commented, “We’re honored that the FDA has granted the RMAT designation to ATSN-201, further underscoring its potential to address the urgent, unmet need in XLRS. This regulatory momentum, coupled with the recent close of our oversubscribed $150 million Series C financing, reinforces our commitment to advancing meaningful gene therapies that have the potential to improve vision and quality of life for individuals living with XLRS and other inherited retinal diseases.”

The LIGHTHOUSE study (NCT05878860), a phase 1/2 safety and tolerability dose-escalation and dose-expansion trial, is currently enrolling male patients ages 6 years and older with a clinical diagnosis of XLRS caused by mutations in the RS1 gene.

About 30,000 male individuals in the US and Europe are affected by XLRS.

Reference

1. Fick K. Atsena Therapeutics – Atsena Therapeutics granted U.S. FDA regenerative medicine advanced therapy designation for ATSN-201 gene therapy to treat X-linked retinoschisis. Atsena Therapeutics. April 15, 2025. Accessed April 15, 2025. https://atsenatx.com/press-release/atsena-therapeutics-granted-us-fda-regenerative-medicine-advanced-therapy-designation-for-atsn-201-gene-therapy-to-treat-x-linked-retinoschisis/