Will We Cure Hearing Loss?

How far are we from a cure for hearing loss? A lot closer than we were five years ago, but no one should put off getting hearing aids or a cochlear implant in the hope of a cure.

The search for a cure is going in many directions: gene therapy, hair-cell regeneration, a drug to protect against noise damage, It is taking place at many locations around the country. I always hesitate to report preliminary positive findings, because I don't want to get people's hopes up. But I do report on significant findings.

Last month a New England biotech company announced that it had received a grant from the Department of Defense to research a therapeutic opportunity that may help reverse hearing loss.

DOD backing is in the department's interest, because hearing loss and tinnitus are the two largest categories of disability claims. War is noisy: A 2015 study of almost 50,000 soldiers showed that peak noise levels in combat can reach 180 dB. Combat veterans have a 63% increased risk for hearing loss. Two and a half million veterans have service-connected hearing disabilities.

Frequency Therapeutics based in Woburn, Mass., and Farmington, Ct., announced that it had received a $2 million grant from the DOD to investigate the restoration of hearing after noise-related damage as a result of military service-related injuries.

Frequency’s Progenitor Cell Activation, or PCA Regeneration, technique, uses a combination of small-molecule drugs to stimulate inner ear progenitor cells to multiply and create new hair cells. Hair cell regeneration happens spontaneously in fish and birds, but not in mammals.

In December, Frequency announced the completion of the first in-human safety and tolerance study of its proprietary drug combination, FX-322. (You can read more about it here.) The drug is injected into the inner ear using a standard intratympanic injection, with the patient awake. The Phase 1 trial was conducted at Victoria Eye and Ear Hospital in Melbourne, Australia, on 9 adults with severe to profound sensorineural hearing loss who were scheduled for cochlear implant surgery 24 hours after receiving the injection.

Humans are born with only 15,000 hair cells in each ear and do not develop any more after birth. Damage to these hair cells over time results in a loss of hearing. Figuring out how to make regeneration happen in mammals would be a major step towards finding a cure for hearing loss, and this goal is being pursued by others in addition to Frequency.

Frequency notes that the PCA Regeneration platform targets the root cause of disease without removing stem cells from the body. This avoids issues that can develop with traditional stem cell or gene therapy, which can affect cells other than those targeted. Frequency’s FX-322 awakens the dormant progenitor cells already in the ear, initiating cell division and differentiation to repair the damaged hair cells.

Frequency hopes this technique can be used elsewhere in the body as well, to restore healthy tissue, and it has a number of other programs in development including preclinical research in muscle regeneration and type 1 diabetes. Frequency plans to initiate a Phase 2 trial for hearing regeneration in the U.S. later this year.

This grant applies only to military personnel with service-related hearing loss, although of course if the technique is found to work it would be available to others with sensorineural hearing loss. More than 48 million Americans of all ages have some degree of hearing loss.

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This study is one of many efforts to find a biological cure for hearing loss. I will be writing about others in the coming months. If you are a researcher with relevant information please email me at katherinebouton@gmail.com

This post is adapted from a post that appeared on my blog Hearing Loss, Hearing Aids, Hearing Help.