Sensorion has provided gene therapy to two more toddlers with congenital deafness after the first child, an Australian infant, received the treatment in the third quarter of 2024.
The French biotech company reported on 27 December 2024 that a third toddler had received the treatment in December. On 18 December it revealed a second infant had undergone injection of its SENS-501 (OTOF GT) gene therapy in France.
Sensorion said that for all patients, the surgical procedure was well tolerated, the intra-cochlear administration of the gene therapy product was uneventful, and no serious adverse events were reported. Encouraging behavioural changes were observed in the first two, it said.
A spokesman for Sensorion told HPA that the first patient was in Australia, the second in France, and the third in one of the two countries.
All have congenital deafness linked to mutations in the OTOF (otoferlin) gene which produces the protein otoferlin, needed to allow inner hair cells in the ear to communicate with the hearing nerve.
He said the Australian child was a 13-month-old male with profound congenital hearing loss and auditory neuropathy. He had pathogenic OTOF variant deafness with present otoacoustic emissions and absent auditory brainstem response.
Pneumonia was experienced before enrolment, and bilateral grommets were placed due to chronic otitis media with effusion four weeks before the gene therapy surgery.
“At 14 months, the boy had a unilateral injection of SENS-501 delivered via the round window using a standard facial recess approach; a vent was provided via stapes footplate,” the spokesman said. “Surgery and the perioperative period were uneventful and the patient was discharged per protocol.”
He said more details would be shared in a webinar in the first quarter of 2025. The next steps for its Audiogene phase 1/2 clinical trial, including planned interactions with the US Food and Drug Administration, would also be revealed.
“We are looking forward to disclosing a fuller set of safety and efficacy measurements with our key opinion leaders in the New Year during which we will report a more complete data release when the follow-up treatment period is long enough for the first treated toddlers,” he said.
“Audiogene is the first and only gene therapy clinical trial addressing a unique homogeneous population of infants and toddlers (six to 31 months), naïve of cochlear implants. Audiogene not only aims at restoring hearing but also enabling the toddlers to acquire and develop normal speech, potentially resulting in an improved quality of life.”
Ms Nawal Ouzren, Sensorion CEO said: “I am very pleased with the progress Sensorion has realised in its phase 1/2 gene therapy clinical trial. The injection of the third and last patient of the first cohort, less than a year after the clinical trial application authorisation, is a major accomplishment for Sensorion.
“I am looking forward to advancing SENS-501 and assessing its ability to restore hearing and enable normal speech acquisition and development in the treated toddlers and infants.”
Sensorion said its objective in targeting the first years of life, when brain plasticity was optimal, was to maximise the chances of young children with pre-linguistic hearing loss to acquire normal speech and language.
It said the OTOF gene played a key role in the transmission of auditory signals between the hair cells of the inner ear and the auditory nerve. When this gene is defective, individuals are born with severe to profound hearing loss. SENS-501 aims to restore hearing by introducing a functional copy of the OTOF gene directly into hair cells via viral vector technology, it added,
“By replacing the defective gene, this therapy aims to restore the normal process of converting sound into electrical signals, enabling patients to regain their hearing ability,” Sensorion said.
The study comprises two cohorts of two doses followed by an expansion cohort at the selected dose. While safety is the primary endpoint of the first part of the dose escalation study, auditory brainstem response (ABR) will be the primary efficacy endpoint of the second part of the expansion.
Potentially game changing
Dr Géraldine Honnet, Chief Medical Officer of Sensorion, said the “potentially game changing hearing loss therapeutic” was being developed in collaboration with the Institut Pasteur.
“Today’s data results confirm an excellent safety profile for the first toddlers treated with SENS-501 and I am happy to report early signs of encouraging behavioural changes in both patients,” she said on 18 December.
Dr Honnet said she was confident Sensorion’s differentiated clinical approach would set new standards in the field of gene therapy for otoferlin deficiency.
“I would like to reiterate my gratitude to the parents of the treated patients for their trust, and to the participating investigators for their ongoing commitment to the Audiogene study and conviction in the potential of SENS-501 to create a new treatment paradigm for this debilitating form of deafness,” she said.
Coordinating investigator of the Audiogene clinical study, Professor Natalie Loundon, is director of the Center for Research in Paediatric Audiology, and a paediatric otolaryngologist and head and neck surgeon at Necker Enfants Malades, AP-HP, in Paris.
“The preliminary results provide satisfactory data on the safety of SENS-501 for patients,” she said. “Gene therapy represents real hope for a therapeutic treatment and improvement in hearing, speech acquisition and quality of life for children born deaf due to DFNB9 mutations.”
Surgery in Sydney
Hearing Practitioner Australia reported in 2024 on the first patient to receive the therapy, an Australian child.
Medical Director of the cochlear implant program at NextSense (formerly Sydney Cochlear Implant Centre director), ENT surgeon Clinical Professor Catherine Birman OAM, performed the procedure in the third quarter of 2024. She revealed details at the 36th World Congress of Audiology (WCA) in Paris on 20 September 2024.
Professor Birman, Clinical Professor at Sydney University and Macquarie University, delivered the intra-cochlear injection of the therapy called SENS-501 and reported initial positive safety results for the patient.
At least seven other children from China, the UK and the US have previously received gene therapy from other companies for the same type of deafness. A conference heard in 2024 that they had hearing restored, ‘marking a new era in deafness treatment.’ Some had cochlear implants in one ear.
More reading
First Australian child to have gene therapy for deafness in pioneering trial
Gene therapy restores hearing in baby and children with genetic deafness
Addressing the root cause of genetic deafness
