A groundbreaking gene therapy trial has resulted in an 18-month-old toddler, Opal Sandy, experiencing sound for the first time in her life. Born with total deafness due to a genetic fault in the OTOF gene, Opal underwent a transformative medical procedure as part of a trial conducted by Cambridge University.
The procedure, involving the infusion of a functional copy of the OTOF gene into Opal's right ear, lasted a mere 16 minutes and was performed just before her first birthday. Within weeks, Opal began to respond to loud sounds, marking a significant milestone in her journey towards hearing.
Opal Sandy’s Case
Opal's parents, Jo and James Sandy expressed their astonishment at witnessing their daughter's response to sound. Jo described the experience as "absolutely mind-blowing," while James initially thought it might be a fluke until he observed Opal's consistent reactions to auditory stimuli.
Over time, Opal's hearing progressed remarkably. After 24 weeks, she could hear whispers, prompting doctors to describe her right ear's hearing ability as "near normal." The family was amazed by Opal's ability to detect soft sounds, including those typically unnoticed in daily life.
Notably, Opal has begun speaking words like "Mama" and "Dada," showcasing the profound impact of gene therapy on her auditory and speech development. Professor Manohar Bance, leading the trial at Cambridge University Hospitals Foundation Trust, hailed the results as "perfect" and a herald of a new era in deafness treatment.
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Chord Trial For Treating Deafness
The gene therapy, developed by Regeneron and tested in the Chord trial involving sites in the U.S., Britain, and Spain, has shown promising outcomes. Opal's success story adds to the growing evidence of the therapy's potential to address congenital deafness, a condition affecting approximately 1.7 in every 1,000 children in the United States according to the World Health Organisation.
The CHORD Clinical Trial is investigating the gene therapy DB-OTO for children diagnosed with OTOF mutations. This trial aims to evaluate various doses of DB-OTO to determine its:
- Safety and tolerability
- Efficacy in reinstating hearing function
DB-OTO is a gene therapy designed to introduce a functional version of the OTOF gene into the inner ear. Administered via injection directly into the inner ear during a surgical procedure under general anaesthesia, DB-OTO's delivery method resembles that of cochlear implant surgery, a longstanding practice dating back to the 1960s for treating infantile deafness.
DB-OTO comprises a modified adeno-associated virus (AAV1) carrying the human OTOF gene. AAV vectors serve as protein shells capable of transporting genetic material to specific cells, facilitating its release to restore cellular function. Subsequently, AAVs are naturally cleared from the body after delivering the genetic payload.
Opal's journey and the data from the Chord trial were recently presented at the American Society of Gene and Cell Therapy annual conference, highlighting the strides made in utilising gene therapy to restore hearing abilities in children with congenital deafness.