Sinclair Research Center is a nonclinical contract research organization (CRO), offering animal efficacy models, investigational new drug (IND) enabling and specialty toxicology services among other research services.
Turner Scientific, a preclinical CRO, specializes in hearing research and provides non-GLP and GLP research services.
Through the exclusive partnership, the companies “hope to rapidly advance the field of otic research, and ultimately support the development of new treatments for hearing loss, tinnitus, and vestibular dysfunction which will benefit patients with few current options,” said Dr. Jeremy Turner, PhD, founder and chief scientific officer of Turner Scientific.
What is ototoxicity?
Ototoxicity involves damage to the ear’s hearing and balance structures. Signs and symptoms include tinnitus, hearing loss, hyperacusis, dizziness, and vertigo.
“The consequences of ototoxicity, like those of other forms of hearing loss and tinnitus, are significant,” said Turner. “Simply by taking an ototoxic medication, a patient can be forced to endure poor communication, reduced quality of life, limited vocational and educational opportunities, and restricted social interactions.”
Turner said the potential for ototoxicity is “great,” with approximately one-third of marketed drugs listing hearing loss, tinnitus, and/or vertigo as possible side effects.
The CROs also aim to reduce the incidence of ototoxicity by enabling new and existing medications to be tested for ototoxic potential before any potential effects are seen in the public.
An example of this, Turner said sildenafil (Viagra) was approved and available for ten years – and prescribed more than 40m times – before the US Food and Drug Administration (FDA) realized its potential to cause permanent hearing loss.
Eleven years after FDA approval, the first non-clinical assessment of the ototoxicity of sildenafil was published. “The benefits of early assessment of ototoxic potential are therefore obvious,” he said.
“By combining their scientific expertise, study execution experience, and industry influence, Turner Scientific and Sinclair Research will work together to improve regulatory guidance regarding the ears and protect patients against ototoxicity.”
An oversight? Auditory system omitted
The Society for Toxicologic Pathology (STP) in 2003 published a position paper at the request of the FDA outlining a minimally acceptable list of 42 core tissues to be examined histologically for all good laboratory practice (GLP) repeat-dose toxicity studies.
“While this list arguably contains every other major organ system, the ears are not included. It is unclear why the auditory system was omitted – the position paper lists four reasons why certain tissue were excluded, but none of these reasons pertain to the ears,” explained Turner.
Though recent discussions with STP and FDA representatives also have failed to reveal a reason for the omission, he said, “It is likely, therefore, that the failure to include the auditory system on the list was an oversight.”
Additionally, the position paper notes that the list is not intended to be complete and other tissues should be tested as appropriate.
"However, it is possible that pharmaceutical and biotechnology companies are influenced to prioritize the toxicity testing of those tissues included on the list simply due to their inclusion," said Turner.