If you know at least two random people, then chances are you know somebody with some degree of hearing loss. For many of those people, it’s just a minor thing – an annoying reason to turn the TV volume up. But for others, it can drastically impact quality of life – no longer able to make out what loved ones are saying, cut off from the music and social life they used to enjoy, and maybe living with endless ringing and buzzing in its place.
A therapy that could reverse hearing loss would be life-changing for millions – and that’s what biotechnology company Frequency Therapeutics, a spinout company from MIT, says they’ve created. Not a hearing aid, not an implant, but a new drug that can give people their hearing back.
“Hearing is such an important sense; it connects people to their community and cultivates a sense of identity,” said Jeff Karp, Frequency Therapeutics co-founder and professor of anesthesia at Brigham and Women’s Hospital, in a statement. “I think the potential to restore hearing will have enormous impact on society.”
So how does this potential cure for hearing loss work? It’s kind of amazing: the drug stimulates progenitor cells – a descendent of stem cells that live in the inner ear – to start new making hair cells.
Making your ears more hirsute may not sound like the obvious cure for hearing loss, but it actually makes a lot of sense. We sometimes think of “hearing” as finishing when the noise hits our eardrum, but that’s only half of the story: after that, the vibrations from the sound waves move on to the ossicles – the three smallest bones in your body. These tiny bones are really neat: they basically act like a hammer hitting a gong that’s next to a loudspeaker. Except teeny.
That “loudspeaker”, aka the cochlea, is where the hair cells come in. It’s a hollow bone in the shape of a spiral – the name actually means “snail shell” – filled with fluid. When that fluid is moved by the vibrations from the noise, up to 15,000 hair cells in the cochlea pick it up, and they’re what finally send the signals to the auditory nerve so that we can hear the original noise.
So: no hair cells, no hearing. The problem is, those cells are very fragile – they can be damaged by certain illnesses and medications, or even just too many loud noises. And once they’re gone, they don’t come back.
Until now, apparently.
“Some of these people [in the trials] couldn’t hear for 30 years, and for the first time they said they could go into a crowded restaurant and hear what their children were saying,” said co-founder and MIT Institute Professor Robert Langer. “It’s so meaningful to them. Obviously more needs to be done, but just the fact that you can help a small group of people is really impressive to me.”
Frequency Therapeutics says they’ve already given the treatment to more than 200 people, and seen significant improvements in patients’ hearing in three out of four clinical trials. The therapy is long-lasting – hearing has been improved for nearly two years in some cases – and it comes in the form of a single injection into the inner ear, making it much simpler and quicker than alternatives like gene therapy.
“I wouldn't be surprised if in 10 or 15 years, because of the resources being put into this space and the incredible science being done, we can get to the point where [reversing hearing loss] would be similar to Lasik surgery, where you're in and out in an hour or two and you can completely restore your vision,” Karp says. “I think we'll see the same thing for hearing loss.”
However, perhaps the most tantalizing aspect of this new therapy is its future potential.
“Tissues throughout your body contain progenitor cells, so we see a huge range of applications,” explained Frequency co-founder and Chief Scientific Officer Chris Loose. “We believe this is the future of regenerative medicine.”
“When we were conceiving of this project, we meant for it to be a platform that could be broadly applicable to multiple tissues,” added Karp.
“To me it’s the tip of the iceberg in terms of what can be done by taking small molecules and controlling local biology.”