An 11-year-old boy, Aissam Dam, has been able to hear for the first time in his life after undergoing a groundbreaking gene therapy at the Children’s Hospital of Philadelphia (CHOP). This medical milestone, a first in the United States, holds promise for patients worldwide suffering from hearing loss caused by genetic mutations.
Aissam Dam was born with profound deafness due to a rare genetic abnormality affecting a single gene. This pioneering gene therapy represents a significant breakthrough that could pave the way for treating various genetic causes of childhood hearing loss.
Surgeon John Germiller, director of clinical research for CHOP’s otolaryngology division, expressed his enthusiasm, stating, “Gene therapy for hearing loss is something that we physicians and scientists in the world of hearing loss have been working toward for over 20 years, and it is finally here. While the gene therapy we performed in our patient was to correct an abnormality in one, very rare gene, these studies may open the door for future use for some of the over 150 other genes that cause childhood hearing loss.”
In patients like Aissam, a faulty gene prevents the production of otoferlin, a crucial protein necessary for the inner ear’s “hair cells” to convert sound vibrations into chemical signals sent to the brain. Otoferlin gene defects are highly uncommon, accounting for 1-8 percent of congenital hearing loss cases.
Aissam underwent a surgical procedure on October 4, 2023, where his eardrum was partially lifted, and a modified virus was injected into the cochlea’s internal fluid. This virus carried functional copies of the otoferlin gene, enabling the hair cells to produce the missing protein and function correctly.
After nearly four months since the treatment in one ear, Aissam’s hearing has significantly improved, with only mild-to-moderate hearing loss remaining. He is now experiencing the sensation of hearing sound for the very first time in his life.
Despite this incredible progress, it is uncertain whether Aissam will learn to speak since the window for acquiring speech in the brain typically closes around the age of five. The US Food and Drug Administration (FDA), which approved the study, initially prioritized older children for safety reasons.
This transformative trial was sponsored by Akouos, Inc., a wholly owned subsidiary of Eli Lilly and Company. Similar studies are currently underway or set to commence in the United States, Europe, and China, where several other children have reportedly been cured.
“As more patients at different ages are treated with this gene therapy, researchers will learn more about the degree to which hearing is improved and whether that level of hearing can be sustained over many years,” Germiller added, offering hope for countless others who may benefit from this remarkable advancement in medical science.