ATSENA is developing ATSN-301, an investigational gene therapy for MYO7A-associated Usher Syndrome Type 1B (USH1B), an inherited disease that causes deafness, vestibular dysfunction, and progressive blindness. IND-enabling studies of ATSN-301 were recently completed, and clinical trial material is being manufactured. There is currently no approved treatment for the vision loss associated with USH1B, while cochlear implants can address deafness. Approximately 20,000 patients in the U.S. and EU have USH1B.

Disease Biology

USH1B is caused by biallelic mutations in the MYO7A gene. Children born with USH1B are deaf from birth, have impaired balance, and begin to progressively lose their central vision in the first decade of life. Because foveal cones are often among the last remaining functional photoreceptors in USH1B patients, preserving them during treatment is critical.

Our Approach

ATSN-301 leverages two of Atsena’s proprietary technologies. ATSN-301 employs AAV.SPR, Atsena’s laterally spreading capsid, which has been evaluated in patients with XLRS, where it demonstrated the ability to spread beyond the subretinal injection site and deliver gene therapy to the fovea from a peripheral injection site, avoiding the need for surgical detachment of the fovea. This is particularly important in USH1B, where foveal cones may represent the patient’s only remaining source of functional vision. Because the MYO7A coding sequence is too large to fit inside a single AAV vector, ATSN-301 also uses Atsena’s dual vector DNA recombination platform to split the gene across two vectors that recombine at the DNA level upon co-delivery, producing full-length MYO7A protein.

Preclinical Data

Preclinical studies have demonstrated above-wildtype MYO7A expression in non-human primate retina, supporting the advancement of ATSN-301 toward clinical development.