Patients treated with Tepezza, the only FDA-approved drug for thyroid eye disease, now face an explicit warning on the product label: hearing loss linked to the biologic may be permanent. The drug won approval in 2020 after a Phase 3 trial showed clear benefit for active disease, but post-approval evidence has steadily sharpened concerns about lasting damage to the inner ear. Prospective clinical studies, audiometry data, and a federal adverse-event database analysis spanning three years all point in the same direction, and some patients have already needed hearing aids as a result of treatment.
Why the permanence warning changed the risk calculus for Tepezza
When the FDA cleared teprotumumab (brand name Tepezza) as the first treatment for thyroid eye disease in 2020, the pivotal OPTIC Phase 3 trial had already flagged hearing impairment events in the treatment arm. At that stage, the events appeared manageable and potentially reversible within the trial’s follow-up window. The label language shifted in 2023, when the FDA added or strengthened wording stating that hearing loss “may be permanent.” That two-word addition carries real clinical weight: it tells prescribers and patients that the risk is not simply a temporary side effect that fades after infusions stop.
The updated structured product labeling on DailyMed lists hearing impairment among adverse reactions occurring at rates of five percent or higher in postapproval trials. For a drug administered by infusion over roughly six months, that rate translates into a meaningful number of affected individuals. The question clinicians and patients now face is whether the visual benefits of Tepezza, which can reduce eye bulging and double vision caused by thyroid eye disease, justify a risk of irreversible hearing damage that was not fully apparent when the drug first reached the market.
Trial data, audiometry studies, and FAERS signals converge on lasting hearing damage
The evidence trail starts with the OPTIC Phase 3 trial, published in a major medical journal, which documented hearing impairment events among patients receiving teprotumumab. Those early reports were limited by the trial’s relatively short follow-up period, and the events were initially characterized as largely reversible. Post-approval research has challenged that characterization.
A prospective observational case series published in Ophthalmic Plastic and Reconstructive Surgery found high rates of new otologic symptoms during teprotumumab treatment. Critically, subjective hearing loss showed incomplete resolution at follow-up. Audiogram testing confirmed sensorineural hearing loss in a subset of treated patients, and some of those patients ultimately required hearing aids. Sensorineural loss involves damage to the cochlea or auditory nerve, a type of deficit that current medicine cannot reverse through surgery or medication.
A separate pharmacovigilance analysis drew on the FDA Adverse Event Reporting System, covering reports filed between the first quarter of 2020 and the first quarter of 2023. That study, published in Otolaryngology–Head and Neck Surgery, quantified reported otologic adverse reactions and found disproportionate reporting of hearing-related events for teprotumumab compared with background rates. FAERS data carry known limitations, including voluntary reporting and incomplete clinical detail, but the signal was consistent with what prospective audiometry cohorts were finding independently.
The convergence matters because each evidence stream compensates for the others’ blind spots. Clinical trials offer controlled conditions but short windows. Prospective audiometry studies provide objective measurements but small sample sizes. FAERS captures real-world breadth but lacks granular patient-level detail. Taken together, they build a case that measurable, lasting hearing changes are not rare outliers but a pattern that grows more visible as exposure data accumulate.
Unanswered questions about dose thresholds and long-term cochlear risk
Several gaps remain in the published record. No study has yet identified a cumulative dose threshold above which the risk of permanent hearing loss rises sharply. Teprotumumab is typically given as eight infusions over about five months, but individual exposure can vary with body weight, infusion timing, and treatment interruptions. Without dose-response data tied to audiometric outcomes, clinicians lack a tool to personalize risk counseling or to justify stopping early in patients who begin to notice subtle changes in hearing.
Baseline hearing status is another blind spot. The pivotal OPTIC trial and subsequent case series did not systematically report pre-treatment audiograms in a way that allows researchers to separate drug-induced damage from pre-existing age-related cochlear decline. Thyroid eye disease tends to affect adults in their 40s through 60s, an age range where some degree of high-frequency hearing loss is already common. A plausible but unproven hypothesis is that teprotumumab’s mechanism, which blocks insulin-like growth factor 1 receptor signaling, interacts with age-related cochlear vulnerability to push patients past a threshold they would not have crossed without the drug. Testing that hypothesis requires longer audiometric follow-up, larger cohorts, and careful adjustment for age, noise exposure history, and other ototoxic medications.
Researchers also have limited insight into whether certain clinical features of thyroid eye disease correlate with higher otologic risk. For example, it is unknown whether patients with more severe orbital inflammation, longer disease duration, or higher thyroid-stimulating immunoglobulin titers experience different rates of hearing complications. Without those correlations, clinicians must rely on broad population-level risk estimates rather than tailored predictions for the person in front of them.
How clinicians are adapting informed consent and monitoring
The label change has already altered how many specialists approach informed consent. Instead of presenting hearing changes as an uncommon and reversible nuisance, clinicians now describe a nontrivial chance of permanent loss, including the possibility of needing hearing aids. For some patients, particularly those whose eye disease is moderate rather than vision-threatening, that reframing can tip the balance toward watchful waiting, local therapies, or surgery rather than systemic biologic treatment.
Otolaryngologists and ophthalmologists are increasingly collaborating on baseline and serial audiograms for patients starting teprotumumab. A structured approach often includes pre-treatment testing, mid-course evaluations after several infusions, and post-treatment follow-up to document any changes. While such protocols are not yet standardized, they offer two advantages: earlier detection of subtle threshold shifts that patients may not notice, and objective evidence that can guide decisions about pausing or discontinuing infusions.
Some centers have also begun counseling patients on practical steps to protect hearing during treatment, such as minimizing exposure to loud environments and reviewing concurrent medications for additional ototoxic potential. These measures cannot eliminate risk from teprotumumab itself, but they may reduce the likelihood that other factors will compound cochlear injury during a vulnerable window.
Balancing sight-saving benefits against auditory harm
For patients with severe thyroid eye disease, the benefits of teprotumumab remain substantial. The Phase 3 trial documented meaningful reductions in proptosis and diplopia, outcomes that translate into improved appearance, comfort, and in some cases preservation of vision. For individuals facing disfiguring eye bulging or compressive optic neuropathy, those gains can be life-changing.
The challenge is that the same therapy can impose a permanent sensory cost. Hearing loss affects communication, social engagement, employment, and mental health. Even mild high-frequency loss can make it harder to follow conversations in noisy environments, and the need for hearing aids brings ongoing expense and adjustment. Patients who chose Tepezza before the permanence warning may feel that they accepted one risk profile and ended up living with another.
Going forward, shared decision-making will hinge on more transparent discussions of uncertainty. Patients should hear not only the headline risk percentages but also what is still unknown: who is most vulnerable, whether dose adjustments can meaningfully lower risk, and how often hearing recovers fully versus partially or not at all. Until larger, longer-term datasets are available, those conversations will necessarily lean on imperfect evidence, but the direction of the data so far argues for caution rather than complacency.
Tepezza’s evolving safety story underscores a broader reality of modern biologic therapies: approval based on strong short-term efficacy does not end the need for vigilance. As postmarketing experience accumulates, labels can and do change in ways that reshape the real-world risk–benefit equation. For thyroid eye disease, that evolution now includes a clear acknowledgment that some patients will trade better vision for worse hearing, and that for a subset, the auditory loss will not go away.
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*This article was researched with the help of AI, with human editors creating the final content.
