Drug Trials for Hearing Loss, Tinnitus Therapies Show Promise

Human trials of drug therapy for otology are few and far between. Whether it’s due to competing advances in amplification technology or the difficulty of determining a mechanism of action that could be consistently targeted by medications, pharmaceutical research has taken a back seat to hearing assistance devices.

But that’s all beginning to change.

In just the last year, several phase 2 and 3 clinical trials of drug therapy for tinnitus and hearing loss have started adding patients. In some of the studies, interim results suggest significant advances. Even gene therapy, long talked about in otology circles but mostly a cancer-focused affair, has been tried in a handful of patients.

Thomas Meyer, PhD, chief executive officer of Auris Medical, a Basel, Switzerland-based company that has launched late-stage clinical trials of AM-101 and AM-111, two targeted intratympanic drugs for tinnitus and hearing loss, said the industry is poised for much-needed breakthroughs. “I believe we are now very close to seeing the arrival of what we call rational pharmacotherapy in inner ear disorders,” Dr. Meyer said.

Barbara Domayne-Hayman, DPhil, chief business officer of Autifony Therapeutics, a U.K.-based company that is actively recruiting U.S. patients for the CLARITY-1 study, the first trial of its kind to assess an oral medication for age-related hearing loss (ARHL), agreed that otologic drug research “is definitely headed in the right direction.”

Thomas Meyer, PhDI believe we are now very close to seeing the arrival of what we call rational pharmacotherapy in inner ear disorders.
—Thomas Meyer, PhD

The advances, she stressed, are sorely needed, given the limits of amplification technology. “Until now, hearing aids have been the primary focus of research and product development,” she said. “The problem with these devices is that they tend to amplify all sound; they don’t always do a very good job helping you interpret speech against a background of noise.” Indeed, she added, “that is why so many people who have been fitted with expensive hearing aids often leave them in the drawer at home; they don’t find them all that helpful in a noisy restaurant or work environment.”

That’s where the CLARITY-1 trial comes in. The phase 2a placebo-controlled, double-blind study’s goal is to assess changes in ARHL after four weeks of treatment in patients treated with the oral investigational drug AUT00063. The drug targets the Kv3 ion channel, “which is present on neurons throughout the auditory processing system,” Dr. Domayne-Hayman said. As patients age, Kv3 ion channel activity tends to decline (J Neurosci. 2004;24:1936-1940). That age-related decline is thought to contribute to auditory processing disorders, she added. “Our goal with AUT00063 is to enhance Kv3 ion channel firing in patients with age-related hearing loss, so that the brain is better able to process and discriminate sounds from background noise,” she said.