Functional, sustained recovery of hearing in Otoferlin-deficient mice using DB-OTO, a hair-cell-specific AAV-based gene therapy

Yoojin Chung; Seth D Koehler; Sarah Cancelarich; Tyler M Gibson; Gabriela Pregernig; Lars Becker; Quynh-Anh Artinian; Joseph W Goodliffe; Ning Pan; Tera M Quigley; Arun Senapati; Peter G Slade; Lillian M Smith; Kathy S So; Xichun Zhang; C Eduardo Corrales; Peter Weber; Lynn E Macdonald; Brian Zambrowicz; Aris N Economides; Christos A Kyratsous; Joseph C Burns; Adam T Palermo; Leah R Sabin; John Lee; Vassili Valayannopoulos; Jonathon P Whitton; Meghan C Drummond

doi:10.1016/j.omtm.2025.101577

Functional, sustained recovery of hearing in Otoferlin-deficient mice using DB-OTO, a hair-cell-specific AAV-based gene therapy

Mol Ther Methods Clin Dev. 2025 Aug 25;33(4):101577. doi: 10.1016/j.omtm.2025.101577. eCollection 2025 Dec 11.

Authors

Yoojin Chung^{1

2}, Seth D Koehler^{1

2}, Sarah Cancelarich¹, Tyler M Gibson², Gabriela Pregernig^{1

2}, Lars Becker^{1

2}, Quynh-Anh Artinian², Joseph W Goodliffe^{1

2}, Ning Pan^{1

2}, Tera M Quigley^{1

2}, Arun Senapati², Peter G Slade^{1

2}, Lillian M Smith², Kathy S So^{1

2}, Xichun Zhang², C Eduardo Corrales^{1

2

3}, Peter Weber⁴, Lynn E Macdonald¹, Brian Zambrowicz¹, Aris N Economides¹, Christos A Kyratsous¹, Joseph C Burns², Adam T Palermo², Leah R Sabin¹, John Lee^{1

2}, Vassili Valayannopoulos^{1

2}, Jonathon P Whitton^{1

2}, Meghan C Drummond¹

Affiliations

¹ Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA.
² Decibel Therapeutics, Inc., Boston, MA 02215, USA.
³ Brigham and Women's Hospital, Boston, MA 02115, USA.
⁴ Boston Medical Center, Boston, MA 02118, USA.

Abstract

Biallelic loss-of-function variants in the Otoferlin gene (OTOF) lead to congenital hearing loss in both humans and mice. We developed DB-OTO, a hair-cell-specific adeno-associated virus (AAV)-based dual-vector gene therapy designed to restore hearing in individuals with OTOF-related hearing loss. DB-OTO is composed of two AAV1 vectors that reconstitute a functional OTOF gene expression cassette to form the full-length human OTOF variant 5 (h OTOFv5). A synthetic promoter (mMyo15) based on the murine Myosin 15 a gene was engineered to restrict the transgene expression to hair cells. The promoter construct was chosen after comparison of multiple variants using a GFP reporter in ex vivo murine explant models, followed by in vivo studies in wild-type mice and cynomolgus macaques. Comparison between the 1.0 kb mMyo15 and a ubiquitous promoter driving expression of h OTOFv5 transgene in mice showed that hair-cell-specific expression is critical for safe expression of otoferlin. DB-OTO induced dose-dependent establishment of auditory brainstem response, and OTOF expression in inner hair cells over a 10-fold dose range sustained for at least 3 months in a mouse model of OTOF deficiency. These data supported the initiation of an ongoing phase I/II clinical trial of DB-OTO in pediatric patients with OTOF-related hearing loss.

Keywords: AAV; DB-OTO; DFNB9; auditory neuropathy; deafness; dual vector; gene therapy; hearing loss; otof; otoferlin.