Hearing loss is a major global health challenge, affecting more than 1.5 billion people worldwide. While many medicines deliver life-changing benefits, more than 200 commonly used drugs can unintentionally cause ototoxicity, damage to the inner ear that may lead to lasting hearing problems.
Ototoxicity can manifest in many ways: hearing loss, tinnitus (ringing in the ears), a sensation of fullness in the ear, dizziness, or vertigo. Symptoms may appear suddenly or gradually, occur individually or in combination, and range from temporary to permanent. Onset can be immediate or delayed by weeks.
For patients, these effects can profoundly impact communication, balance, and overall quality of life. For drug developers, unexpected ototoxicity can derail promising therapies, delay regulatory approval, and erode investor confidence.
Why Monitoring Ototoxicity Matters
Ototoxicity is shaped by drug class, dosing regimen, and patient susceptibility. High-risk classes include certain antibiotics (aminoglycosides, macrolides), platinum-based chemotherapies (such as cisplatin), loop diuretics, antimalarials, and pain relievers like NSAIDs and aspirin. As novel therapies emerge, from targeted oncology agents to regenerative biologics, the need for predictive and translational auditory safety assessments is rapidly increasing.
Yet, ototoxicity assessment is rarely required in preclinical or clinical development, and traditional toxicology studies often overlook auditory endpoints. This gap leaves developers vulnerable to costly late-stage surprises. Incorporating dedicated ototoxicity monitoring earlier can reduce risk, strengthen regulatory interactions, and most importantly, safeguard patients.
Ex Vivo Models: Translating Complexity
Complementing cell-based assays, ex vivo cochlear explant preparations provide a high-fidelity view of drug effects within a preserved cochlear structure. These models maintain hair cells, supporting cells, ribbon synapses, and spiral ganglion neurons, enabling detailed mapping of damage across cochlear regions and rigorous dose-response analysis under controlled conditions.
Figure 1. Representative images of rat cochlear explants, with or without cisplatin exposure. Cisplatin-treated explants show loss of hair cells, fibers, and neurons compared to controls. Cilcare’s cochlear explant model enables drug screening for compounds that protect auditory tissue from cisplatin-induced ototoxicity.
