Chijioke Iremeka
Otolaryngologists and healthcare specialists who manage conditions involving the ears, nose, and throat have described a recent groundbreaking gene therapy and cochlear implants for both children born with deafness and adults experiencing hearing loss as a significant breakthrough in restoring hearing capabilities.
The specialists noted that the latest advancements in gene therapy and cochlea implants are revolutionary for individuals with deafness, while clinical trials have demonstrated the potential for restoring hearing even after many years of deafness, regardless of whether the individual is an adult or a child.
The experts referenced recent research published in the peer-reviewed journal, Nature Medicine, which reported that bilateral administration of human OTOF gene therapy seems to be safe.
The study suggested that this approach could effectively treat a rare form of hereditary hearing loss by improving speech perception, sound source localisation, and the overall auditory experience.
According to the study, the novel gene therapy designed to target a form of inherited deafness restored hearing function in five children who were treated in both ears, indicating that the children also experienced better speech perception and gained the ability to localise and determine the position of the sound.
The study, the world’s first clinical trial to administer a gene therapy to both ears (bilaterally), demonstrates additional benefits than what was observed in the first phase of this trial, published earlier this year when children were treated in one ear.
The research was led by investigators from Mass Eye and Ear, a member of the Mass General Brigham healthcare system, and Eye & ENT Hospital of Fudan University in Shanghai, while its findings were published June 5, 2024, in Nature Medicine.
According to the co-senior author, Dr Zheng-Yi Chen, who is an associate scientist in the Eaton-Peabody Laboratories at Mass Eye and Ear, “The results from these studies are astounding.”
“We continue to see the hearing ability of treated children dramatically progress and the new study shows added benefits of the gene therapy when administrated to both ears, including the ability for sound source localisation and improvements in speech recognition in noisy environments.”
The researchers noted their team’s goal was always to treat children in both ears to achieve the ability to hear sound in three dimensions, a capability important for communication and common daily tasks such as driving.
“Restoring hearing in both ears of children who are born deaf can maximise the benefits of hearing recovery,” said lead study author, Director of the Diagnosis and Treatment Centre of Genetic Hearing Loss affiliated with the Eye & ENT Hospital of Fudan University in Shanghai, Professor Yilai Shu.
He further said the new results showed the approach holds great promise and warrants larger international trials as over 430 million people around the world are affected by disabling hearing loss, of which congenital deafness constitutes about 26 million.
Shu. noted that up to 60 per cent of childhood deafness is caused by genetic factors, saying that children with DFNB9 are born with mutations in the OTOFgene that prevent the production of functioning otoferlin protein, which is necessary for the auditory and neural mechanisms underlying hearing.
This new study, according to the Nature Medicine, is the first clinical trial to use bilateral ear gene therapy for treating DFNB9, stating that the new research presents an interim analysis of a single-arm trial of five children with DFNB9 who were observed over either a 13-week or 26-week period at the Eye & ENT Hospital of Fudan University in Shanghai, China.
During the procedure, Shu explained that he injected functioning copies of the human OTOF transgene carried by the adeno-associatedvirus into the inner ears of patients through a specialised, minimally invasive surgery.
PUNCH Healthwise learnt that the first case of bilateral treatment was conducted in July 2023 and during follow-up, 36 adverse events were observed, but no dose-limiting toxicity or serious events occurred.
All five children showed hearing recovery in both ears, with dramatic improvements in speech perception and sound localisation, the authors noted.
They held that two of the children gained an ability to appreciate music, a more complex auditory signal, and were observed dancing to music in videos captured for the study, while the trial remains ongoing with participants continuing to be monitored.
PUNCH Healthwise reports that in 2022, this research team delivered the first gene therapy in the world for DFNB9 as part of a trial of six patients in China treated in one ear and the trial, which had results published in The Lancet(medical journal) in January 2024, showed five of six children gained improvements in hearing and speech.
Shu initially presented the data at the 30th annual congress of the European Society of Gene and Cell Therapy in Brussels, Belgium in October 2023, becoming the first in the world to report clinical data on using gene therapy to restore hearing.
He said, “These results confirm the efficacy of the treatment that we previously reported on and represent a major step in gene therapy for genetic hearing loss.
“Our study strongly supports treating children with DFNB9 in both ears, and our hope is this trial can expand and this approach can also be looked at for deafness caused by other genes or non-genetic causes,” added Chen, who is also an associate professor of Otolaryngology-Head and Neck Surgery at Harvard Medical School.
“Our ultimate goal is to help people regain hearing no matter how their hearing loss was caused,” saying that there are currently no drugs available to treat hereditary deafness, which has made room for novel interventions like gene therapies.
The authors, however, noted that more work is needed to further study and refine the therapy.
Meanwhile, specialists who spoke exclusively with PUNCH Healthwise in different interviews said the latest gene therapy and cochlea implant are game changers for people with deafness as they will help restore hearing loss.
A Consultant Ears, Nose, and Throat specialist at the Iyi-Enu Mission Hospital, Ogidi, Anambra State, Dr King Madueke, said the gene therapy will be a great relief for people living with deafness.
“Though is not yet in the country right now, its clinical trials showed that it is something that we will look forward to as well as other hearing treatments. Before this breakthrough, the cochlea implant gave this exciting remedy for people with childhood deafness.
“I will not foreclose medical research because it gives rise to more research. So, I will be excited to see it happen in Nigeria and people with deafness can regain their hearing abilities, which will improve the quality of their lives,” he added.
According to an online medical portal, Mayo Clinic, a cochlea implant is an electronic device that improves hearing, which can be a choice for people who have severe hearing loss from inner ear damage and couldn’t hear well with hearing aids.
Mayo Clinic said that a cochlea implant sends sounds past the damaged part of the ear straight to the hearing nerve, called the cochlear nerve, saying that for most people with hearing loss that involves the inner ear, the cochlear nerve works.
“Cochlea implants use a sound processor that fits behind the ear and pulls in sounds from outside the ear. It sends sound signals to a receiver that is been placed under the skin behind the ear.
“The receiver sends the sound signals down an attached thin wire. The wire holds tiny sound electrodes that have been placed in the snail-shaped inner ear, called the cochlea.
“The signals trigger the cochlea nerve. The nerve sends the signals to the brain. The brain hears those signals as sounds. These sounds are like natural hearing, but not quite the same.
“It takes time and training to learn to hear the signals from a cochlear implant as words. Within three to six months of use, most people with cochlea implants make big gains in understanding speech,” the Mayo Clinic added.
A Professor and Chief Consultant Otolaryngologist at the University of Maiduguri Teaching Hospital, Maiduguri, Borno State, Mala Sandabe, who noted that the therapy is a game changer, said it would make people with deafness to hear again.
Prof Sandabe
He highlighted that the treatment has the potential to address two types of deafness, congenital deafness in individuals born with the condition and acquired deafness in those who lost their hearing during their lifetime, adding that it suggests a broad applicability of the treatment across different stages of life.
While acknowledging the need for further research into gene therapy, Sandabe also pointed out that cochlea implants, though expensive, offer hope to individuals with deafness.
He, however, emphasised that not all deaf individuals are suitable candidates for cochlea implants, highlighting the importance of considering various factors in determining the most appropriate treatment options for each individual.
According to the National Library of Medicine, the cochlea is a fluid-filled, spiral-shaped cavity found in the inner ear that plays a vital role in the sense of hearing and participates in the process of auditory transduction.
Sandabe explained, “There are individuals who are suitable candidates for cochlear implants, while others are not. For example, children born with deafness and who have been deaf for seven to 10 years may not benefit from cochlear implants, as the device may not be effective for them at that stage.
“This device transmits electronic impulses into mechanical impulses, stimulating the part of the brain responsible for hearing. When a child is actively engaged in speech and auditory activities, this region of the brain remains active.
“However, if there is a prolonged absence of such stimulation, the brain may adapt and deactivate, rendering the implant less effective after a certain period, typically around 10 years.
“At this point, the cochlea implant will not work for such a person. So, it needs an evaluation to determine which person needs a cochlea implant or not.”
Sandabe highlighted the fragility of the device, emphasising that it can get damaged if it falls and this explains why manufacturers have agents stationed in hospitals where the implants are being placed.
He said the agents handle the devices carefully until they are ready to be implanted, ensuring their integrity and effectiveness.
Sandabe stated that implant alone costs between $15, 000 and $20, 000, excluding the cost of surgery and rehabilitation.
Discussing methods to reduce costs, Sandabe remarked, “While this is the price set by manufacturers, it’s notably cheaper in India. In fact, individuals from the United Kingdom and various other regions opt to undergo the procedure there due to the cost savings.
“The Indian government negotiated with manufacturers to procure a large quantity of cochlea implants at a discounted rate of approximately $10 each. These were then distributed to hospitals where they were needed.
“This arrangement allowed the government to purchase the implants at a reduced cost, making them more accessible to the general population. The Nigerian government could consider a similar approach to make cochlea implants more affordable and accessible to those in need,” he said.
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