Atsena shares positive early data in ocular gene therapy trial

Atsena Therapeutics announced positive clinical data results from Part A of the LIGHTHOUSE study, a phase 1/2 clinical trial evaluating subretinal injection of ATSN-201 for the treatment of X-linked retinoschisis (XLRS), a genetic condition that leads to blindness.

ATSN-201 is a gene therapy product candidate that 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. AAV.SPR 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.

Part A of the LIGHTHOUSE study evaluated the tolerability and safety of three different doses of ATSN-201 administered through subretinal injection in three patients per cohort, for a total of nine adult patients. ATSN-201 was well tolerated in all nine patients with XLRS in Part A, and no serious adverse events related to treatment were reported.

The majority of patients demonstrated successful efficacy readouts across structural measurements (foveal schisis closure) and had meaningful improvement on visual function measurements including microperimetry (measures light perceived in parts of the retina), best corrected visual acuity (measures vision with corrective lenses) and low luminance visual acuity.

XLRS is a monogenic X-linked disease caused by mutations in the RS1 gene which encodes retinoschisin, a protein secreted primarily by photoreceptors. It primarily affects males and is typically diagnosed in early childhood. Approximately 30,000 males in the U.S. and EU have XLRS, for which there are currently no approved treatments.

Back in April, Atsena announced the successful close of an oversubscribed $150 million Series C financing, the proceeds of which are being used to advance the ATSN-201 gene therapy program.