Cleared in Effort to Create a Pill to Improve Hearing Loss for
Millions of Seniors
U. of Florida
researchers think they have opened the way for research to move
forward on hearing-loss drugs for older and younger Americans
Jan. 17, 2013 –
A pill to make you hear better? A joy to millions of senior citizens
suffering with hearing loss. It maybe closer than you think.
University of Florida researchers say they have solved one of the
problems that has slowed development of a hearing pill.
A new way to
test anti-hearing-loss drugs in people could help land those
medicines on pharmacy shelves sooner. University of Florida
researchers have figured out the longstanding problem of how to
safely create temporary, reversible hearing loss in order to see how
well the drugs work.
"There's a real
need for drug solutions to hearing loss," said lead investigator
Colleen Le Prell, Ph.D., an associate professor in the department of
speech, language, and hearing sciences at the UF College of Public
Health and Health Professions.
"Right now the
only options for protecting against noise-induced hearing loss are
to turn down what you're listening to, walk away from it or wear ear
plugs, and those options may not be practical for everyone,
particularly for those in the military who need to be able to hear
findings are described in the November/December 2012 issue of the
journal Ear & Hearing.
About 26 million
American adults have noise-induced hearing loss, according to the
National Institute on Deafness and Other Communication Disorders.
Prevention is key, because damage to hearing-related hair cells in
the inner ear by loud noise is irreversible.
Though hearing aids can
help amplify sound and implanted devices can restore some sensation
of sound for those with more profound hearing loss, they do not
restore normal hearing. Thus, researchers are trying to find drugs
that prevent hearing damage in the first place.
prototype drugs have prevented noise-induced hearing loss in
laboratory animals, it has been hard to know whether the same
protection is possible in humans, largely because researchers lacked
an effective method for the needed tests.
Those tests are now
achievable because of the UF efforts. The work brings scientists
closer to the development of drugs that could help protect people at
risk of hearing damage — from rock concert goers to factory workers
and military personnel who are routinely exposed to noise as they
Le Prell's model
is the first to use controlled music levels to reliably cause
low-level, temporary hearing loss in human participants. Other
studies have used beeps or tones, user-selected music levels, or
music exposures that don't result in temporary hearing loss.
monitoring boards ensured that studies of the UF model met national
safety standards for research in humans. Co-investigator Patrick
Antonelli, M.D., the George T. Singleton Professor and chair of the
UF department of otolaryngology, provided onsite supervision of
study participant safety, and collaborators at the University of
Michigan and Southern Illinois University were involved in study
design and safety discussions.
"Dr. Le Prell
started with a unique idea to create a reversible noise-induced
hearing loss and has established solid groundwork for this new model
in the use of clinical drug testing," said hearing expert Jianxin
Bao, Ph.D., an associate professor of otolaryngology and biology and
biomedical sciences at Washington University School of Medicine in
St. Louis, who was not involved in the UF study. "As for every new
model, several unknown factors exist for this elegant experiment
model, which requires further detailed studies."
temporary hearing loss, study participants listened to rock or pop
music on a digital music player via headphones for four hours at
sound levels ranging from 93 decibels — the noise level of a power
lawn mower — to 102 decibels, the noise of a jackhammer. Each
participant got a hearing test four times, 15 minutes to
three-and-a-quarter hours after his or her listening session, as
well as follow-up tests one day and one week later.
after the music stopped, those who listened to the highest music
levels had lost just a small amount of hearing — six decibels, on
average. Hearing returned to normal within three hours.
Le Prell's group
will use this testing model in two first-of-a-kind clinical trials
of therapeutics designed to determine if noise-induced hearing loss
can be prevented in humans. The first study uses a dietary
supplement called Soundbites, manufactured by Hearing Health
Science, a University of Michigan bioscience spinoff company.
Soundbites contains the vitamin A precursor beta carotene, vitamins
C and E and the mineral magnesium. This antioxidant formula, the
patent for which Le Prell shares, has prevented temporary and
permanent hearing loss in laboratory animals.
In the other
ongoing study, participants take a drug called SPI-1005 produced by
Sound Pharmaceuticals Inc. The test capsule contains a new molecule
called ebselen that mimics a protective inner ear protein.
The Food and
Drug Administration will monitor the studies to ensure openness,
analytical rigor and participant safety as the researchers try to
get badly needed drugs onto the market.
"We really want
to find out what's going to work and we want to make it possible for
strategies that do work to get in the hands of the people who need
them," Le Prell said.