An 11-year-old with hereditary hearing loss underwent gene therapy at the Children's Hospital of Philadelphia (CHOP), making history as the first patient to undergo gene therapy treatment for hereditary hearing loss in the United States.
Gene Therapy Treatment: A First in the US
The aim of gene therapy for children with OTOF-mediated hearing loss is to reinstate hearing capabilities. This is achieved by introducing normal otoferlin genes (OTOF) into the inner ear, enabling sensory cells to operate effectively.
These functional genes are packaged within a viral vector, a modified version of a harmless virus, facilitating their delivery into the cochlea cells of the inner ear. The vector solution is administered directly into the internal fluid of the cochlea during the procedure.
According to John A. Germiller, MD, Ph.D., an attending surgeon and Director of Clinical Research at CHOP, this achievement in gene therapy for hearing loss has been a goal for professionals in the field for over two decades.
The recent success involves correcting an abnormality in a rare gene, the otoferlin gene (OTOF).
The study's first patient, an eleven-year-old with OTOF-mediated hearing loss, underwent gene therapy at CHOP, making history as the first instance of gene therapy used to potentially treat hereditary hearing loss in the United States.
Aissam Dam, an 11-year-old boy, spent his childhood in complete silence, born deaf and having never experienced sound. Residing in an impoverished community in Morocco, he communicated through a self-invented sign language and lacked access to formal education.
Upon relocating to Spain, his family recently sought the expertise of a hearing specialist, who unexpectedly proposed the possibility of Aissam participating in a clinical trial involving gene therapy.
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The surgical procedure, performed on October 4, 2023, involved delivering a single, small dose of gene therapy (AK-OTOF) directly into the inner ear using an endoscope. This method, a first in the U.S., utilized the "round window," a small entry point into the cochlea.
The patient, initially born profoundly deaf in both ears, has experienced a remarkable improvement in hearing, now exhibiting only mild to moderate hearing loss in the treated ear.
The success of this investigational gene therapy offers hope for future applications in treating the over 150 other genes causing childhood hearing loss.
Genetic mutations can contribute to hearing loss, with more than 150 implicated genes identified to date.
The gene therapy designed for OTOF-mediated hearing loss aims to restore hearing by introducing copies of normal OTOF genes into the inner ear.
Encased in a viral vector, these genes are delivered into the cochlea's cells, allowing them to function and respond to sound stimuli, ultimately activating the auditory nerve.
Advancement of Clinical Trial on Gene Therapy
CHOP's involvement in the AK-OTOF-101 clinical trial, sponsored by Akouos, Inc., a subsidiary of Eli Lilly and Company, signifies a collaborative effort in advancing gene therapy breakthroughs.
Dr. Germiller's earlier work on a minimally invasive endoscopic round window surgical approach laid the foundation for the delivery method used in this gene therapy procedure.
As the clinical trial progresses, researchers aim to gain insights into the sustained improvement of hearing levels over time.
This groundbreaking success with 11-year-old Aissam Dam provides valuable information for directing future efforts to benefit a broader range of patients experiencing hearing loss.
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