International experts publish guidelines on the administration of gene therapy for hereditary hearing loss

Up to 60% of congenital and early-onset hearing loss is caused by genetic mutations in an inherited gene, and gene therapy has recently emerged as a potential treatment option. To provide a standardized framework for conducting safe, high-quality clinical trials, a group of international experts has put together guidelines on the administration of gene therapy for hereditary hearing loss. Publishing in the Cell Press journal Med on October 23, the guidelines highlight the need for patient-centered care and respect for the diversity of perspectives within the hearing loss community. 

Cochlear gene therapy holds transformative potential for treating genetic hearing loss. This consensus provides essential guidance to help ensure that future clinical trials are conducted safely and effectively, at a time when the field is advancing rapidly." 

Zheng-Yi Chen, senior author of Harvard Medical School in Cambridge, MA, USA

"Although no gene therapies for hearing loss have yet been commercialized, several clinical trials are already underway around the world," says senior author Yilai Shu of Fudan University in Shanghai, China.

So far, gene therapy trials for hearing loss have shown promising results, particularly for inherited deafness caused by mutations in the OTOF gene-a gene that is integral to a person's ability to hear. These treatments employ a viral vector that contains a functional copy of the mutated gene. The engineered virus is delivered directly into the inner ear. 

Gene therapies for diseases such as hemophilia and retinal disorders have established frameworks designed to protect patient safety and promote positive therapeutic outcomes, but until now, there was no standard guidance on gene therapy for hearing loss. 

"If there is no standardized consensus, differences in trial design and outcomes measurement could hinder data comparability and integration," says Shu. "This consensus provides a unified framework to guide current and future clinical trials and to ensure the safety, consistency, and reliability as the field advances." 

In the new guidelines, the authors expand on frameworks for other gene therapies and highlight a number of points, including patient selection criteria, which includes confirmation of genetic mutations and ensuring patients are the appropriate age; surgical procedures and methods aimed at ensuring safe and effective drug delivery; safety and follow-up instructions detailing a systematic safety evaluation and long-term (at least 5 years) patient follow-up; and efficacy evaluation, or measuring improvements in auditory function and speech perception. 

"This consensus marks a major milestone for the field of cochlear gene therapy," says Lawrence R. Lustig of Columbia University in New York, USA. "As gene therapy for hereditary hearing loss moves from concept to clinical reality, this global effort ensures that progress is driven by safety, scientific rigor, and collaboration." 

The authors hope that their consensus statements will help a wide range of people involved with gene therapy, including clinicians, researchers, trial sponsors, hospitals, healthcare institutions, regulatory authorities, ethics committees, and rehabilitation specialists. They note that as trials progress and new treatments are developed, updates and refinement to the guidelines will likely be needed. 

The team highlights the need for patient-centered care and respect for the diversity of perspectives within the hearing community to ensure that the field advances with both integrity and compassion for those impacted by hearing loss. 

"We respect the diversity of perspectives within the deaf community," Shu says. "The final choice of whether to consider one of these treatments belongs to the adequately informed family, and their decisions should be respected." 

This work was supported by The National Natural Science Foundation of China, the National Key Research and Development Program of China, the Science and Technology Commission of Shanghai Municipality, the 2024 Annual Medical Service and Security Capacity Enhancement Project: National Key Clinical Specialty, the Shanghai Municipal Education Commission, the Shanghai Municipal Health Commission, Fudan University, German Research Foundation, Multiscale Bioimaging EXC, and Collaborative Research Center 1690.