Atsena Doses First Patient in XLRS Gene Therapy Clinical Trial

Atsena Therapeutics, a company developing gene therapies for inherited retinal diseases (IRDs), has dosed the first person in a Phase 1/2 clinical trial for its X-linked retinoschisis (XLRS) gene therapy, ATSN-201. Known as the Lighthouse Study, the clinical trial is evaluating ATSN-201 in male patients ages 6-64 with a clinical diagnosis of XLRS caused by pathogenic or likely pathogenic mutations in the gene RS1. The 18-participant clinical trial is taking place at the Children’s Hospital of Los Angeles and the Oregon Health & Science University.

Atsena’s emerging XLRS gene therapy is injected subretinally (underneath the retina). The company says this approach gets the treatment more effectively to the area of the retina where the treatment is needed – i.e., the cavities in the central retina caused by the splitting of retinal layers. The gene therapy uses a specially designed adeno-associated viral delivery system (AAV.SPR) that is able to reach the fragile fovea, the tiny pit in the central retina responsible for visual acuity, without an injection in the foveal region. The AAV.SPR was designed in the lab of Shannon Boye, PhD, a retinal gene therapy pioneer from the University of Florida and co-founder of Atsena.

“Dosing the first patient in the LIGHTHOUSE study marks a significant milestone for Atsena and the XLRS community,” said Kenji Fujita, MD, chief medical officer at Atsena Therapeutics, in a press release. “We are excited to be utilizing AAV.SPR in the clinic, as it has the potential to revolutionize the treatment of XLRS, as well as other inherited retinal disorders. Spreading laterally beyond the subretinal injection site, AAV.SPR facilitates the safe delivery of RS1 to photoreceptors in the central retina/fovea.”

The RD Fund, the Foundation’s venture philanthropy fund for advancing emerging treatments into and through early stage clinical trials, is a founding investor in Atsena.

XLRS is caused by mutations in the gene RS1 which expresses a protein called retinoschisin — a protein that plays a critical role in the maintenance of the retinal structure and cell-to-cell adhesion. As an X-linked condition, XLRS usually affects males with females as unaffected carriers. XLRS is usually diagnosed in boys before the age of 10. Approximately 30,000 people in the US and EU are affected by XLRS.

Atsena has also reported vision improvements for patients in a Phase 1/2 gene therapy clinical trial for Leber congenital amaurosis 1 (LCA1) which is caused by GUCY2D mutations. The company also has a dual-vector gene therapy in preclinical development for Usher syndrome 1B, which is caused by MYO7A mutations.