Regeneron Pharmaceuticals won approval Thursdayfor its gene therapy for hearing loss, completing what has for nearly a decade been a milestone in the making—for the company and gene therapy more broadly.

Otarmeni, which was approved under the FDA’s Commissioner’s National Priority Voucher (CNPV) program, is intended for individuals with congenital deafness caused by a deficiency of the otoferlin protein, which is critical to the hearing process. It is the first treatment to address an underlying cause of hearing loss and Regeneron’s first approved gene therapy. The company will provide Otarmeni for free in the U.S.

The company has “a lot invested in” the modality, Aris Baras, senior vice president and general manager at the Regeneron Genetics Center, told BioSpace prior to Otarmeni’s approval. Otarmeni is “really our first foray” into genetic medicine, Baras said. Regeneron currently does not list any other gene therapy assets in its pipeline, but the company has published preclinical data in other organs.