By Geoffrey Waring
The loss of one’s voice can be a devastating development, and its reasons are myriad. Sometimes, through the natural aging process or because of trauma or surgery, the vocal folds can grow stiff or atrophy. The result is, in the worst case, a total loss of voice, which can affect quality of life, work, and personal expression, among other things.
Current treatments are available, though many are not effective and can involve invasive surgery. This can be difficult for patients, and includes the risks and inconvenience of going under anesthesia. The physician-scientists at the USC Caruso Department of Otolaryngology-Head and Neck Surgery and the USC Voice Center are running a series of clinical trials to try to speed up the availability of non-invasive therapeutics that can effectively treat this problem.
“A lot of foundational work is going on for rejuvenation of tissue in the larynx and the vocal folds, but the timeline for bringing that to people is really slow,” Michael Johns III, MD, director of the USC Voice Center, said. “We have the techniques and the tools but we don’t have the therapeutics, and we’re waiting for science to develop them. Or we can borrow treatments that have already been developed for other applications and apply them. Hence the idea for this program for rapid testing of novel injectable therapeutics.”
There are three cornerstones of regenerative medicine: matrix, growth factors, and stem cells. Stem cell research comes with a whole host of complications, but growth factors and matrix are known to be safe and effective in other applications. The clinical trial program at the USC Voice Center is trying to test products that have already been proven safe and effective for treatment in other fields—in cosmetic surgery, for example—and apply them to treating vocal fold trauma or atrophy.
The program started with a clinical trial of Silk Voice, an FDA-approved treatment for glottal insufficiency. The idea was to create the infrastructure to quickly test FDA-approved materials for application in the vocal folds.
“That was for us to test out our processes,” Dr. Johns explained. “We have the same outcome measures, we have similar problems, and we have new injectables. The idea was to build the infrastructure, the baseline data points, and the outcome measures that we collect, so we could rapidly test new materials.”
Following the clinical trial for Silk Voice, the USC Voice Center performed a second clinical trial for a Platelet Rich Plasma (PRP) injectable, a substance that has shown promising regenerating properties in fields like cosmetic surgery and hair loss. That trial was completed in 2022, and a new trial of a product called Renuva, an injectable fat matrix, is currently being led by Karla O’Dell, MD. Glottal insufficiency can effectively be treated with the injection of harvested fat, which is a good injectable substitute for the vocal folds, but the procedure can be cumbersome. Renuva may offer a good, off-the-shelf alternative that is equally effective.
“The benefit is that traditionally when fat was used you’d have to harvest the fat from someone, and you’d have to inject it through a larger needle which needs to be done in the operating room,” Dr. O’Dell explains. “With Renuva, it’s off-the-shelf ready, you don’t need to do liposuction, and you can perform the injection in the office.”
She went on to say that Renuva may have benefits over other injectables as well.
“For a vocal fold paralysis that may not recover, we’re always looking for a product that can be long lasting,” she said. “Fat is nice and soft, you don’t want something hard and firm because the vocal folds need to vibrate and you want something that can potentially last forever so additional procedures are not necessary.”
If the trials show these to be safe and effective treatments, the benefits are potentially enormous for those who have lost their voices. Research on novel treatments for glottal insufficiency is typically slow, as funding is directed at life-threatening diseases and conditions. This is very reasonable, but for people who have lost their voices, it leaves a difficult set of options: to learn to live without a voice, or to undergo costly and invasive procedures to treat the problem. These trials will help present more palatable, effective options for patients looking for improvements without going under the knife.
The trials are currently ongoing and will continue for approximately one year, because Dr. O’Dell is looking to see if Renuva is viable as a long-term treatment option. So far, the results have been promising.
“It appears to be an option for injection augmentation and is working comparably well with the other injectables that are currently being used,” Dr. O’Dell said. “How long the benefit from Renuva will last is to be determined, but it’s exciting because none of the currently available treatments last long term.”
The infrastructure the USC Voice Center has put into place will continue to serve science as an innovative way to quickly and effectively test treatments that are currently being used in other areas but may also have application for treatment of the voice.
Dr. Johns is proud of the work the USC Voice Center has done in this regard.
“Our overall goal is to bring treatments that are available in medical sciences that have not been applied to the larynx so we can have new treatments sooner, rather than having to wait for new development out of the lab for something that’s probably not coming fast.”