Atsena Therapeutics receives Orphan Drug Designation from FDA for ATSN-201 gene therapy to treat X-linked retinoschisis

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Atsena Therapeutics, announced that the FDA has granted Orphan Drug Designation for ATSN-201 for the treatment of X-linked retinoschisis (XLRS).

According to the company, ATSN-201, a gene therapy product candidate, leverages AAV.SPR, Atsena’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.

Patrick Ritschel, CEO of Atsena Therapeutics, said in a news release that the company was honored to earn the FDA’s Orphan Drug Designation for ATSN-201, which was also recently had been granted Rare Pediatric Disease designation.

“These designations mark a significant inflection point for the potential of this ocular gene therapy in an inherited retinal disease that currently has no available treatments,” Ritschel, said in a statement. “The Atsena team is passionate and committed to our ongoing work on the XLRS program. We look forward to bringing hope to patients affected by this rare disease and are confident these designations will expedite our path forward.”

The FDA grants Orphan Drug Designation to drugs and biologics that are intended for safe and effective treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000 people in the United States. That designation offers certain incentives, such as tax credits toward the cost of clinical trials upon approval and prescription drug user fee waivers.

If a product is given Orphan Drug Status by the FDA, that product is entitled to 7 years of market exclusivity for the disease in which it has Orphan Drug designation. That is independent from intellectual property protection.

XLRS is a monogenic 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.

Currently, there are no approved treatments for XLRS, which is typically diagnosed in early childhood and affects approximately 30,000 males in the United States and European Union.

The safety and tolerability of ATSN-201 is currently being evaluated in the LIGHTHOUSE study (NCT05878860), a Phase I/II, open-label, 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 this study is ongoing.

AAV.SPR, one of Atsena’s novel capsids, spreads laterally beyond the subretinal injection site to enable safe and efficient transduction of the central retina (where schisis cavities predominate in XLRS patient retinas) when injected into areas outside the macula.

In August 2024, Atsena Therapeutics announced the FDA granted Rare Pediatric Disease designation (RPD) for ATSN-201 for the treatment of X-linked retinoschisis (XLRS).²

References:

1. Atsena Therapeutics. Atsena Therapeutics Receives Orphan Drug Designation from the U.S. FDA for ATSN-201 Gene Therapy to Treat X-linked Retinoschisis. GlobeNewswire News Room. Published September 17, 2024. Accessed September 17, 2024. https://www.globenewswire.com/news-release/2024/09/17/2947307/0/en/Atsena-Therapeutics-Receives-Orphan-Drug-Designation-from-the-U-S-FDA-for-ATSN-201-Gene-Therapy-to-Treat-X-linked-Retinoschisis.html

2. Hutton D. Atsena Therapeutics receives Pediatric Disease Designation from the FDA for ATSN-201 gene therapy to treat X-linked retinoschisis. Ophthalmology Times. Published August 14, 2024. Accessed September 17, 2024. https://www.ophthalmologytimes.com/view/atsena-therapeutics-receives-pediatric-disease-designation-from-the-fda-for-atsn-201-gene-therapy-to-treat-x-linked-retinoschisis