Gene therapy allows two children with congenital deafness to hear

A recent abstract presented at the American Society of Cell and Gene Therapy (ASCGT) annual conference highlighted results from Regeneron Pharmaceuticals' ongoing Phase 1/2 CHORD trial. The trial showed that treatment with the DB-OTO gene therapy restored hearing in two congenitally deaf patients.

According to the Regeneron press release, DB-OTO is an investigational cell-selective gene therapy, delivered with an adeno-associated virus (AAV). The virus delivers a functional copy of the otoferlin gene through a direct injection into the cochlea. The newly introduced gene is controlled by the MYO15 promoter, which helps ensure the gene is only expressed in the inner hair cells.

The CHORD study is a first-in-human, multicenter, open-label phase 1/2 clinical trial to test DB-OTO’s preliminary efficacy, safety, and tolerability. Regeneron recruits patients in the United States, United Kingdom, and Spain. Part A of the trial delivers singular intracochlear injections of DB-OTO in one ear. Meanwhile, Part B of the study will administer simultaneous singular intracochlear injections of DB-OTO in both ears based on the selected dose from Part A.

According to the abstract presentation, one child dosed at 11 months old improved hearing to normal levels within 24 weeks of treatment. Another patient who was dosed at four years old had improved hearing during the 6-week assessment.

“The opportunity of providing the full complexity and spectrum of sound in children born with profound genetic deafness is a phenomenon I did not expect to see in my lifetime,” said Lawrence R. Lustig, MD, Chair of Columbia University’s Department of Otolaryngology, Head & Neck Surgery and a clinical trial investigator, in the Regeneron press release. “These impressive results showcase the revolutionary promise of DB-OTO as a potential treatment for otoferlin-related deafness, and we are excited to see how this translates into an individual’s development, especially since early intervention is associated with better outcomes for speech development. With the DB-OTO CHORD trial now enrolling participants in sites across the U.S. and Europe, we’re part of the beginning of a new era of gene therapy research that looks to create treatment options that address the root cause of profound genetic deafness.”