Hearing is an intricate process: Sound travels down the ear canal, vibrates the eardrum, makes its way to the cochlea and its tiny hair cells, which vibrate and send signals to the brain.
Dr. Lloyd Klickstein, head of translational medicine at Novartis, said in an interview that other species are able to regenerate hair cells.
“Birds, for example, need hair cells to know how to fly,” he said. “Fish have hairs in their lateral lines so they are able to school and know what’s nearby and if they lose their hair cells they get new ones.”
Novartis is now working on a new treatment where a harmless virus carries a gene into the inner ear to stimulate new growth of hair cells.
“Once the virus injects the DNA into the cell it then takes over the cell’s machinery to make the new protein and that protein will now cause the non-hair cell to become a hair cell,” Lustig said.
Klickstein said that the new gene therapy promises to be much better tolerated and less cumbersome and will one day render cochlear implants and hearing aids obsolete.
“What we hope to do with this therapy is restore hearing as normal as possible,” Klickstein said, “no device maintenance, no complications— just normal hearing.”
The treatment looks promising, but there are still obstacles. For one thing, the treatment washes out of the ear, so the effects may be temporary.
“The delivery might be one of the biggest problems we face,” Klickstein said. “The inner ear is encased almost completely in solid bone and getting the gene therapy to the right cells was one of our biggest challenges.”
Otonomy, a biotech company, has invented a gel that is injected into the ear and allows medication to stay in place longer. Experts at Otonomy and Lustig both indicated that they see the treatments being combined to provide a cure.
Lustig said that Big Pharma’s growing interest in the new treatments signals that there is a great promise. The goal is to restore hearing without aides or surgery and to have the effects last.