Tepezza (teprotumumab-trbw), a monoclonal antibody treatment approved by the FDA for thyroid eye disease (TED), has become the subject of significant mass tort litigation due to reports of permanent hearing loss and auditory dysfunction in patients who received the drug. Patients across the country have filed lawsuits alleging that Horizon Therapeutics, the manufacturer, failed to adequately warn consumers about these serious auditory side effects despite clinical evidence suggesting the risks. The Tepezza hearing loss mass tort represents one of the more concerning product liability cases in recent years, with hundreds of plaintiffs claiming life-altering hearing damage that has not reversed even after discontinuing the medication.
The litigation stems from the drug’s mechanism of action and its administration protocol. Tepezza is administered intravenously in eight infusions over a 24-week period, and mounting reports indicate that patients have experienced sudden hearing loss, tinnitus (ringing in the ears), and auditory processing difficulties during or after treatment. For many plaintiffs, this hearing loss has been permanent and substantial enough to require hearing aids or cochlear implants, fundamentally affecting their quality of life, work capacity, and ability to communicate. The legal claims focus on whether Horizon Therapeutics adequately disclosed these risks in the drug’s labeling and marketing materials before the FDA eventually added hearing loss warnings in 2023.
Table of Contents
- What is Tepezza and How Does It Cause Hearing Loss?
- The Timeline of Safety Warnings and FDA Action
- Who Has Been Affected and What Are Typical Hearing Loss Patterns?
- Legal Claims and Damages in Tepezza Mass Tort Litigation
- Challenges in Proving Causation and Liability
- Settlement Trends and Case Resolution
- Regulatory and Clinical Implications Looking Forward
- Conclusion
- Frequently Asked Questions
What is Tepezza and How Does It Cause Hearing Loss?
Tepezza was approved by the FDA in January 2020 for the treatment of thyroid eye disease, a rare autoimmune condition affecting the eye muscles and tissues. The drug works by targeting and inhibiting the insulin-like growth factor-1 (IGF-1) receptor, which plays a role in the inflammatory process underlying TED. While the mechanism effectively reduces inflammation around the eyes and improves symptoms in the majority of TED patients, the same biological pathway it targets exists in the inner ear, where it plays a crucial role in maintaining auditory function. This overlap between the drug’s intended therapeutic target and its effects on auditory structures creates the biological foundation for hearing complications.
The hearing loss associated with Tepezza is believed to result from cochlear toxicity, damage to the delicate structures of the inner ear responsible for processing sound. Patient reports document cases of sudden sensorineural hearing loss—the most serious type, involving damage to the nerve pathways transmitting sound—occurring during the treatment course or shortly afterward. One patient in her 50s reported that her hearing deteriorated so rapidly during her Tepezza infusions that she went from mild hearing loss to severe bilateral deafness within weeks, requiring her to abandon her career in education. The auditory damage appears to be dose-dependent, with some patients experiencing progressive worsening with each of the eight infusions, though others report sudden onset after a single dose.
The Timeline of Safety Warnings and FDA Action
When Tepezza received FDA approval in 2020, the drug’s labeling did not include warnings about hearing loss as an adverse effect. The initial clinical trials and safety data submitted to the FDA were based on relatively small patient populations followed for limited periods, and hearing loss either was not monitored closely or was not adequately reported during those trials. However, as Tepezza entered wider clinical use, reports of hearing problems began accumulating through the FDA’s adverse event reporting system (FAERS) and through patient and physician communications to the manufacturer. By 2022 and into 2023, the volume of hearing loss reports had become impossible to ignore, prompting regulatory action.
In August 2023, the FDA issued a warning letter to healthcare providers about the risk of sudden sensorineural hearing loss associated with Tepezza and required the addition of a warning to the drug’s label. This action came approximately three and a half years after the drug’s initial approval—a significant delay during which thousands of patients received the medication without formal warning of the hearing risk. The FDA’s action was notable because it represented a tacit acknowledgment that hearing loss was a real and serious adverse effect that should have been communicated to patients and providers earlier. A critical limitation of this FDA warning is that it came too late for patients who had already suffered permanent hearing damage; the warning did not and cannot reverse the hearing loss that occurred before the label update.
Who Has Been Affected and What Are Typical Hearing Loss Patterns?
Hearing loss from Tepezza has been reported across various patient demographics, though it appears to affect both men and women, younger and older patients, with some cases involving individuals in their 30s and others in their 70s. The hearing loss is often characterized as sudden sensorineural hearing loss affecting one or both ears, sometimes accompanied by tinnitus, vertigo, or a feeling of fullness in the affected ear. Some patients report noticing symptoms between infusions, while others describe an acute change occurring shortly after an infusion or even months after completing the full course of treatment. The variability in onset and severity has made it difficult for the medical community to establish clear predictive risk factors, meaning that patients cannot easily be screened to identify who is most vulnerable before beginning treatment.
One documented case involved a patient who developed profound bilateral hearing loss after her fourth Tepezza infusion, leaving her unable to hear normal conversation even with hearing aids. She reported that neither her rheumatologist nor her infusion center staff had mentioned hearing loss as a possible risk, leaving her completely unprepared for the sudden change. Another patient experienced gradual progressive hearing loss throughout the treatment course, ultimately requiring bilateral cochlear implants—a surgical intervention with its own risks and recovery period. The timing and presentation patterns suggest that the hearing damage mechanism may be cumulative and dose-dependent, though individual variability is significant.
Legal Claims and Damages in Tepezza Mass Tort Litigation
The mass tort litigation against Horizon Therapeutics centers on several core legal theories: failure to warn, inadequate labeling, negligent misrepresentation, and, in some cases, fraudulent concealment. Plaintiffs argue that Horizon Therapeutics knew or should have known about the hearing loss risk before the FDA warning was issued, based on adverse event reports, clinical trial data, post-marketing surveillance information, and communications from healthcare providers. The legal claim is not necessarily that the drug caused hearing loss in a few isolated cases, but rather that Horizon failed to disclose a material risk to patients and physicians who would have made different medical decisions had they been properly informed.
Comparing this to other mass torts, the hearing loss claims are similar to litigation involving other pharmaceutical products where the manufacturer allegedly concealed serious side effects. Damages in Tepezza hearing loss cases typically include compensation for medical expenses related to hearing loss treatment (hearing aids, cochlear implants, audiology care), lost wages for patients who had to leave employment due to communication difficulties, pain and suffering for the permanent disability, and in some cases punitive damages if evidence shows reckless or intentional misconduct by Horizon. The variation in damages reflects the spectrum of hearing loss severity—a patient with mild, manageable high-frequency hearing loss may recover less than a patient who became completely deaf and requires cochlear implant surgery. However, a tradeoff exists: while larger settlements can provide more comprehensive compensation, they often involve longer litigation timelines and require more plaintiffs to reach critical mass before defendants are motivated to settle.
Challenges in Proving Causation and Liability
One significant challenge in Tepezza hearing loss litigation is establishing causation—that is, proving that the hearing loss was caused by Tepezza rather than by other factors. Hearing loss is a condition with multiple potential causes, including advanced age, noise exposure, genetics, other medications, infections, and other underlying health conditions. Defendants will argue that many plaintiffs may have developed hearing loss regardless of Tepezza exposure, making it difficult to establish that the drug directly caused the loss rather than simply coinciding with it. Epidemiological and medical literature must be developed to establish that the rate of sudden sensorineural hearing loss in Tepezza patients exceeds what would be expected in the general population—a complex and expensive process requiring expert testimony and statistical analysis.
A critical limitation is that while animal toxicology and in vitro studies can show that substances damage auditory structures, human causation must be demonstrated through careful analysis of clinical data and patient populations. Additionally, the defense will likely argue that Horizon provided warnings as soon as sufficient evidence accumulated to warrant them, or that warnings were not warranted based on the initial safety database. Plaintiffs must overcome the legal hurdle of showing not only that hearing loss occurred and that Tepezza was taken, but that the company’s failure to warn about the risk constituted negligence or that the company knew about the risk but concealed it. This is considerably more difficult than simply showing that a patient took the drug and later developed hearing loss. Defense experts will testify about what information was reasonably available at the time the drug was approved and marketed, and they will argue that the company updated the label as soon as the FDA identified the risk through post-marketing surveillance—the intended function of the regulatory system.
Settlement Trends and Case Resolution
Settlement discussions in Tepezza hearing loss litigation are ongoing, though no global settlement has been reached as of 2026. Individual cases are resolving at varying amounts depending on the severity of hearing loss, the age and work status of the plaintiff, and the strength of evidence in particular cases.
Some cases have settled for amounts ranging from tens of thousands to several hundred thousand dollars, while litigation continues in other jurisdictions and venues. The pharmaceutical industry’s experience with similar mass torts suggests that a global settlement may eventually be negotiated, likely involving a settlement fund with claims-made procedures where hearing loss patients can submit documentation of their condition and receive compensation based on a schedule. A typical example from similar product liability cases is the establishment of settlement criteria requiring medical documentation of the hearing loss, which must meet specified thresholds to qualify for compensation.
Regulatory and Clinical Implications Looking Forward
The Tepezza hearing loss litigation has prompted renewed scrutiny of how FDA-approved medications are monitored for adverse effects in clinical practice, particularly for rare or unexpected side effects that may not manifest until thousands of patients have been treated. The case highlights the tension between rapid approval of drugs for serious diseases (thyroid eye disease is debilitating and had limited treatment options before Tepezza) and the complete safety assessment that typically requires years of post-marketing surveillance.
Going forward, the FDA and pharmaceutical manufacturers may implement more robust monitoring protocols for drugs targeting inflammatory pathways or those affecting delicate sensory systems. The litigation also serves as a cautionary reminder to healthcare providers that FDA-approved status does not guarantee complete safety disclosure, and that vigilance about emerging adverse effects remains essential.
Conclusion
The Tepezza hearing loss mass tort litigation represents a significant example of pharmaceutical product liability where patients allege that a medication approved for a serious condition caused permanent auditory damage due to inadequate pre-market disclosure and delayed warning information. Hundreds of patients across the United States have filed lawsuits claiming that Horizon Therapeutics failed to adequately warn about hearing loss risks before they received the drug, resulting in permanent hearing loss, tinnitus, and other auditory complications that have required hearing aids, cochlear implants, and substantial lifestyle changes. The litigation is ongoing, with cases resolving individually and potential for broader settlement discussions as more evidence and causation expert opinions emerge.
If you believe you have experienced hearing loss or other auditory damage after receiving Tepezza infusions, you should consult with an audiologist to document your hearing status and with an attorney experienced in pharmaceutical mass tort litigation to discuss your legal options. The time to file claims is limited by statutes of limitations, which vary by state but typically range from two to four years from the time you discovered the injury. Gathering medical records documenting your Tepezza treatment, hearing loss diagnosis, and any resulting treatment or lifestyle impact will be essential to support a potential claim.
Frequently Asked Questions
How long after Tepezza infusions can hearing loss occur?
Hearing loss has been reported during the treatment course, between infusions, and months after completing all eight infusions. There is no single timeline, and the variable onset makes it difficult to predict when symptoms may appear.
Is the hearing loss from Tepezza permanent?
Yes, in documented cases to date, the hearing loss has been permanent and has not reversed after discontinuing Tepezza. Some patients have required hearing aids or cochlear implants to manage the loss.
What should I do if I develop hearing loss after Tepezza treatment?
See an audiologist for formal hearing testing, document your Tepezza treatment dates and infusions, and consult with a mass tort attorney to evaluate whether you may have a claim. Report your symptoms to the FDA’s adverse event system (MedWatch) as well.
Can Horizon Therapeutics be held liable if it updated the warning label?
The FDA warning label update in 2023 does not shield Horizon from liability for failing to warn patients who were treated before the warning was added. The litigation alleges that the company should have disclosed the risk earlier based on available evidence.
What compensation can I expect from a Tepezza hearing loss lawsuit?
Compensation varies based on the severity of hearing loss, impact on employment and quality of life, and medical treatment costs. Cases have settled for amounts ranging from tens of thousands to hundreds of thousands of dollars, but individual outcomes depend on specific circumstances.
How do I know if my hearing loss was caused by Tepezza versus other causes?
Establishing causation requires medical documentation of your hearing before and after Tepezza treatment, audiological evaluation, and expert medical testimony. Your attorney and retained medical experts will work to establish the connection between Tepezza exposure and your hearing loss.