In short
Adeno-associated viral vector serotype 44.9 containing the human HRS1 gene, also known as ATSN-201, is an investigational gene therapy being studied for X-linked retinoschisis, an inherited retinal disease. One clinical trial, a Phase 3 study, is currently authorised and plans to enrol 76 participants.
Key points
- ATSN-201 is a gene therapy that delivers the human RS1 gene to the retina.
- It is being studied in a Phase 3 clinical trial for X-linked retinoschisis.
- The trial is currently authorised and plans to enrol 76 participants.
- The main measure is change in visual function using microperimetry.
- The therapy is given by subretinal injection at a dose of 11,000,000,000 vector genomes per mL.
What is adeno-associated viral vector serotype 44.9 containing the human HRS1 gene?
Adeno-associated viral vector serotype 44.9 containing the human HRS1 gene, also known as ATSN-201, is an investigational gene therapy. It belongs to a class of treatments that use a modified virus — an adeno-associated virus (AAV) — to deliver a healthy copy of a gene into cells. In this case, the vector carries the human retinoschisin (RS1) gene. The substance has no marketing authorisation in the trial records and is still being investigated in clinical research.
How does it work?
ATSN-201 delivers a functional copy of the RS1 gene to cells in the retina using an AAV serotype 44.9 vector. The RS1 gene provides instructions for making retinoschisin, a protein that helps hold the layers of the retina together. In people with X-linked retinoschisis, mutations in the RS1 gene lead to a missing or faulty retinoschisin protein, causing the retinal layers to split and impairing vision. By delivering a working copy of the gene, the therapy aims to restore retinoschisin production and support retinal structure and function.
Which conditions is it used or studied for?
- X-linked retinoschisis — an inherited retinal dystrophy caused by dysfunction in the human retinoschisin (RS1) gene. The condition mainly affects males and leads to splitting of the retinal layers, causing reduced vision from an early age.
How is it given?
ATSN-201 is administered by subretinal injection, a procedure in which the therapy is injected beneath the retina. In the authorised clinical trial, the product is prepared at a concentration of 11,000,000,000 vector genomes per millilitre (vg/mL).
What do the clinical trials show?
One clinical trial, NCT05878860, is authorised to evaluate ATSN-201 in people with RS1-associated X-linked retinoschisis. The study is a Phase 3 interventional trial with a planned enrolment of 76 participants. The primary outcome measure is the change from baseline in microperimetry across prespecified locations in the study eye for participants aged 12 years and older. Microperimetry is a test that measures light sensitivity at specific points on the retina. The study aims to determine the effect of ATSN-201 on visual function.