Tepezza Hearing Loss Lawsuit

What Is the Tepezza Hearing Loss Lawsuit About?

The Tepezza hearing loss lawsuit involves claims that Tepezza (teprotumumab), an intravenous medication used to treat Thyroid Eye Disease (TED), causes hearing damage in a dramatically higher percentage of patients than its manufacturer originally disclosed. Published studies have found that 50-65% of patients who receive Tepezza infusions develop some form of hearing problem, including hearing loss, tinnitus (ringing in the ears), and autophony (abnormally hearing one's own voice, breathing, or heartbeat). Many of these hearing problems are permanent.

Tepezza was approved by the FDA in January 2020 as the first and only medication specifically approved for Thyroid Eye Disease. It was developed and marketed by Horizon Therapeutics, which was subsequently acquired by Amgen for $27.8 billion in October 2023. The federal lawsuits are consolidated in MDL 3079 in the Northern District of Illinois before Judge Manish S. Shah.

Plaintiffs allege that Horizon Therapeutics failed to adequately warn patients and physicians about the true risk and severity of hearing damage associated with Tepezza. The original prescribing information cited a hearing impairment rate of approximately 10% based on clinical trial data, but post-marketing studies revealed the actual rate to be 5 to 6 times higher. The FDA required a label update with stronger hearing warnings in July 2022, but plaintiffs contend this came too late for thousands of patients who were already harmed. Legal analysts widely expect the Tepezza litigation to settle in 2026, given the strength of the scientific evidence and Amgen's financial resources. For another pharmaceutical lawsuit involving inadequate warnings, see our page on the Ozempic stomach paralysis lawsuit.

How Tepezza Causes Hearing Damage

Tepezza (teprotumumab) works by blocking the insulin-like growth factor-1 receptor (IGF-1R), which plays a key role in the autoimmune process behind Thyroid Eye Disease. However, IGF-1R is also present in the inner ear, where it plays an important role in auditory function. Researchers believe that Tepezza's blockade of IGF-1R in the inner ear disrupts normal hearing mechanisms, leading to damage.

The drug is administered as a series of 8 intravenous infusions over approximately 24 weeks. Hearing problems can begin during the infusion course or shortly after completion. Importantly, many patients do not experience full recovery of their hearing after discontinuing treatment, suggesting that the damage to inner ear structures may be permanent in a significant number of cases.

Hearing Problems Reported by Patients

Post-marketing studies have revealed that hearing problems from Tepezza are far more common and severe than originally reported. The following hearing conditions have been documented in patients who received Tepezza infusions:

• Hearing loss: Ranging from mild to severe, hearing loss is the most serious complication associated with Tepezza. Some patients experience sudden hearing loss during or shortly after infusions, while others notice gradual deterioration. In many cases, the hearing loss does not fully resolve after discontinuing treatment.
• Tinnitus: Persistent ringing, buzzing, hissing, or other sounds in the ears. Tinnitus can be constant or intermittent and can significantly impact quality of life, sleep, concentration, and mental health.
• Autophony: A condition where patients hear their own voice, breathing, or heartbeat with abnormal loudness or clarity. This occurs due to dysfunction of the eustachian tube and can be extremely distressing and disorienting.
• Eustachian tube dysfunction: Impaired function of the tube connecting the middle ear to the throat, causing ear fullness, pressure, and muffled hearing.
• Ear pain and pressure: Persistent discomfort, fullness, or pain in one or both ears.

Who Qualifies for the Tepezza Lawsuit?

Eligibility for the Tepezza hearing loss lawsuit is based on whether you received Tepezza infusions and subsequently developed hearing-related conditions. The following criteria are used to evaluate potential claims:

Lawsuit Timeline

The Tepezza hearing loss litigation is a relatively new but fast-developing mass tort. Here are the key dates and milestones in the litigation:

Settlement Amounts

As of early 2026, the Tepezza hearing loss litigation has not yet reached a settlement, but legal analysts widely expect settlement negotiations to advance significantly in 2026. Several factors make this litigation likely to settle: the scientific evidence showing hearing damage in 50-65% of patients is exceptionally strong, Amgen has substantial financial resources following its $27.8 billion acquisition of Horizon Therapeutics, and the number of pending claims continues to grow.

The estimated settlement ranges below are based on the types and severity of hearing injuries and comparable pharmaceutical litigation. Individual claim values will depend on the permanence and severity of hearing damage, the impact on quality of life, and the strength of medical documentation.

Key factors that will influence individual claim values include: the degree of hearing loss documented by audiograms, whether the hearing damage is permanent, the presence and severity of tinnitus, the impact on daily activities and quality of life, pre-treatment hearing records showing normal hearing, and the number of Tepezza infusions received. For background on how mass tort settlements work generally, see our guide on mass tort settlement amounts and how settlement funds are distributed.

How to File a Tepezza Lawsuit Claim

If you received Tepezza infusions and have experienced hearing problems, here is the process for filing a claim:

For a detailed walkthrough of the general process, read our guide on how to join a mass tort lawsuit. You can also learn about how mass tort attorneys get paid through contingency fees — you owe nothing unless you receive compensation. If you are wondering about the role of legal counsel, see our guide on whether you need a lawyer for a mass tort claim.

Named Defendants

The Tepezza hearing loss lawsuit names the following defendant:

• Horizon Therapeutics (now Amgen) — Horizon Therapeutics developed Tepezza and brought it to market in 2020. Horizon was acquired by Amgen for $27.8 billion in October 2023. Amgen, as the successor company, has assumed liability for the Tepezza litigation. Plaintiffs allege that Horizon knew or should have known that Tepezza caused hearing damage at rates far higher than disclosed in the original prescribing information, and that the company failed to adequately warn patients and physicians about this risk.

The claims in the Tepezza lawsuit include failure to warn, negligence, strict liability, breach of warranty, and fraud/misrepresentation. Plaintiffs contend that Horizon Therapeutics prioritized sales of its blockbuster drug — Tepezza generated approximately $1.9 billion in revenue in 2022 — over patient safety by downplaying the hearing damage risk. Amgen now faces the litigation as successor to Horizon, with the significant financial resources to fund a resolution. For another case involving a major pharmaceutical acquisition affecting litigation, see the CPAP machine (Philips Respironics) lawsuit.

Medical and Scientific Evidence

The scientific evidence connecting Tepezza to hearing damage is among the strongest in any current pharmaceutical mass tort. Multiple published studies have confirmed hearing problems at rates far exceeding the original label disclosures:

• Post-marketing clinical studies: Multiple peer-reviewed studies published after Tepezza's approval found that 50-65% of patients experienced some form of hearing problem during or after treatment. These studies used audiometric testing (formal hearing tests) to objectively measure hearing changes, providing stronger evidence than self-reported symptoms alone.
• IGF-1R mechanism: Scientific research has established that the insulin-like growth factor-1 receptor (IGF-1R) — the target that Tepezza blocks — plays a critical role in inner ear function, including the survival and function of hair cells in the cochlea that are essential for hearing. Blocking this receptor is a biologically plausible mechanism for hearing damage.
• FDA adverse event reports: The FDA's FAERS (FDA Adverse Event Reporting System) database contains a significant number of adverse event reports related to Tepezza and hearing problems, contributed by both patients and healthcare providers.
• FDA label update: The FDA's requirement in July 2022 that Horizon update the Tepezza prescribing information with stronger hearing warnings is itself evidence that the regulatory agency recognized the hearing risk was more significant than originally characterized.
• Clinical trial data reanalysis: Reanalysis of the original clinical trial data has suggested that hearing problems may have been underreported or undercharacterized during the trials that supported FDA approval, raising questions about the adequacy of safety monitoring during the drug development process.

The strength of the scientific evidence — particularly the objectively measured hearing damage rates of 50-65% — is a major factor in the expectation that this litigation will settle. For another case where hearing damage is central to the litigation, see the 3M Combat Arms Earplugs lawsuit.