International Experts Publish First Consensus Guidelines for Hearing Loss Gene Therapy Trials

October 23, 2025 — A group of international experts has established the first standardized consensus guidelines for conducting clinical trials of gene therapy for hereditary hearing loss. Published in the journal Med, the framework aims to ensure safe, high-quality, and comparable data as the field rapidly advances.

Up to 60% of congenital and early-onset hearing loss is due to genetic mutations. While gene therapies for diseases like hemophilia have established trial frameworks, none previously existed for hearing loss, a gap that risked hindering data integration.

“Cochlear gene therapy holds transformative potential for treating genetic hearing loss,” says senior author Zheng-Yi Chen of Harvard Medical School. “This consensus provides essential guidance to help ensure that future clinical trials are conducted safely and effectively.”

A Unified Framework for Safety and Efficacy

Several clinical trials for inherited deafness, particularly those targeting the OTOF gene, are already underway globally and have shown promising early results. These treatments typically involve delivering a functional copy of the gene directly into the inner ear using a viral vector.

The new guidelines provide a unified framework by expanding upon existing gene therapy standards, covering critical areas:

• Patient Selection: Criteria for confirming genetic mutations and ensuring the appropriate age for treatment.
• Surgical Procedures: Methods designed to guarantee safe and effective drug delivery into the inner ear.
• Safety and Follow-up: Mandating a systematic safety evaluation and long-term patient follow-up of at least five years.
• Efficacy Evaluation: Standardized measures for quantifying improvements in auditory function and speech perception.

Yilai Shu of Fudan University, also a senior author, emphasized that without this consensus, differences in trial design could undermine data reliability.

Patient-Centered Care and Community Respect

The authors strongly emphasize the need for patient-centered care and respect for the diversity of perspectives within the hearing loss community.

“The final choice of whether to consider one of these treatments belongs to the adequately informed family, and their decisions should be respected,” said Dr. Shu.

The consensus is intended to guide all parties involved—from clinicians and trial sponsors to regulatory authorities and ethics committees—as gene therapy for hereditary hearing loss moves from concept to clinical reality. As trials progress and new treatments emerge, the guidelines are expected to be refined and updated.