Shanghai-based Refreshgene Therapeutics has announced that ten of the 11 patients dosed in a trial of its otoferlin (OTOF) gene therapy have had their hearing restored.
During a presentation at the American Society of Gene & Cell Therapy (ASCGT) 2024 Conference, taking place in Baltimore, US, results were presented from the study conducted in collaboration with Harvard Medical School.
The patients were diagnosed with autosomal recessive deafness 9 (DFNB9), caused by mutations of the OTOF gene. RRG-003 is an adeno-associated virus (AAV) serotype 1 carrying a human OTOF transgene, which is designed to treat patients with DFNB9.
The Phase 0, single-arm trial (ChiCTR2200063181) enrolled 11 patients between one and 18 years of age with severe-to-complete hearing loss. AAV1-hOTOF was administered into one or two cochlea’s.
The primary outcome was dose-limiting toxicity (DLT) but investigators also monitored adverse events (AEs), immune response, auditory function and speech perception.
No DLTs were observed but 80 AEs were observed, with 97.5% being Grade 1 or 2, and 2.5% being Grade 3. In all patients with hearing recovery, speech perception was improved.
In the first patient, hearing recovered to 68dB at four weeks, 53dB at 13 weeks, and 45dB at 26 weeks. In patients three to six, the improvement measured was 48dB, 38dB, 40dB, and 55dB at 26 weeks. In patients seven to nine, improvements in the left ear were reduced to 58dB, 85dB and 50dB and in the right ear, 58dB, 75dB, and 55dB at 26 weeks. In patients ten and 11, improvements were 78dB and 63dB at 13 weeks.
DFNB9 landscape
DFNB9 is characterised by congenital or prelingual, severe-to-complete, bilateral hearing loss. There are no treatments currently available for congenital deafness.
On 8 May, Regeneron announced a win at the ASCGT conference after its gene therapy NAME restored hearing in two children. The trial is still recruiting, with plans to enrol 22 children with OTOF hearing loss.
Sensorion and Akouos, an Eli Lilly subsidiary, are two other companies developing therapies for OTOF HEARING LOSS.
Akouos also shared data from its Phase I/II trial of AK-OTOF-101 with patients benefiting from improved hearing. Meanwhile, Sensorion received the green light to start Phase I/II clinical trial of its gene therapy SENS-501 in Europe in January 2024.
