Breakthrough drugs offer hope for the 360 million people with hearing loss
Maybe you sat too close to those ginormous stage speakers at a Jefferson Airplane concert back in the day. Or your earbuds have been turned up way too loud for far too long. Or you're just growin' old.

Those are among the various reasons why tens of millions of people — including 15 percent of the adult population in the United States — experience hearing loss, now a public health epidemic.

Hearing aids and cochlear implants that amplify sounds are traditional, if limited, solutions, but now breakthrough medical remedies are in the works. Currently, several biotechnology companies are developing novel drug therapies that promise to actually repair inner-ear damage and restore normal hearing.

As with many of the human body's systems, from eyesight to libido, hearing naturally declines with age. But ever since the industrial revolution and the rise of clanky machines, the volume of everyday life has reached cacophonous proportions and contributed to hearing loss — and not just with old folks.

According to statistics compiled by the National Institutes of Health, about three out of every 1,000 children in the United States are born with a detectable level of hearing loss in one or both ears. One in eight Americans (30 million) age 12 years or older has hearing loss in both ears. Close to 38 million Americans age 18 and over report some trouble hearing. Worldwide, hearing loss afflicts 360 million people.

There are existing drugs for effectively treating middle-ear infections, "but nothing that works on the cochlea," said Paula Cobb, executive vice president of corporate development at Decibel Therapeutics, a Boston-based start-up launched in 2015 with $52 million in venture capital from biotech investment firm Third Rock Ventures and SR One, the VC arm of pharma giant GlaxoSmithKline .

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Cobb was referring to the very small spiral tube encased within the inner ear, which contains the nerve endings that transmit sound vibrations from the middle ear to the auditory nerve. "It's a poorly understood organ in the middle of one of the hardest bones in the body," Cobb said. Noise-induced damage to the nearly 15,000 tiny hair cells and neurons in the cochlea or to the auditory nerve is by far the leading cause of what's known as sensorineural hearing loss.

In order to develop drugs to accurately target either the auditory nerve or hair cells, Decibel's researchers delve into the anatomy of the inner ear, down to the cellular level. "If you don't do the fundamental work to understand what you're trying to achieve and actually getting the drug in there, it's shooting in the dark in terms of doing clinical development," Cobb said.

In late November, Decibel entered into a partnership with Regeneron, a biotech drug developer in Tarrytown, New York. Besides accessing Regeneron 's robust research tools, particularly in genetics, Decibel also will benefit from its financial support. Decibel, however, retains worldwide development and commercialization rights to any products discovered in the collaboration and will pay Regeneron tiered royalties based on net sales.