From Miracle Drug to Mass Tort: Tepezza and Permanent Hearing Loss
Tepezza (teprotumumab-trbw) represented a genuine therapeutic breakthrough when Horizon Therapeutics brought it to market in January 2020: the first FDA-approved drug specifically for thyroid eye disease (TED), a potentially disfiguring autoimmune condition causing eye protrusion, double vision, and inflammation. For TED patients who previously had limited treatment options short of orbital decompression surgery, Tepezza offered meaningful clinical benefit. The mass tort litigation doesn't dispute this benefit, it focuses on what Horizon didn't tell patients about a serious, potentially permanent adverse effect.
Post-market reports beginning in 2021 identified a pattern: a significant proportion of Tepezza-treated patients were experiencing hearing loss and tinnitus, in some cases, permanent and severe hearing damage. A 2021 case series published in Ophthalmology and Therapy documented hearing-related adverse events in six of 10 consecutive Tepezza patients (60%). Consulting pharmaceutical class action attorneys can help evaluate your specific claim. A 2022 study in JAMA Ophthalmology reported hearing-related adverse events in 65% of patients in one cohort. These are extraordinarily high adverse event rates for a drug whose prescribing information, as of the time of many infusions, listed hearing impairment as a low-frequency risk without adequate quantification of its true incidence.
The Failure-to-Warn Theory
Tepezza's label did include hearing loss as an adverse reaction, but plaintiffs argue the disclosure was materially inadequate in two respects. First, the incidence rate: a drug that causes hearing loss in potentially 60% of patients requires a far more prominent and quantitative warning than a general adverse reaction listing. FDA labeling regulations (21 C.F.R. § 201.57(c)(7)) require that serious adverse reactions be characterized by incidence in a way that allows physicians and patients to make genuinely informed risk-benefit decisions.
Second, the permanence: plaintiffs allege Horizon's early label and marketing materials suggested hearing effects might be reversible when the emerging clinical evidence showed many patients experienced lasting or permanent damage. The distinction is enormous for patient consent, a temporary hearing disturbance during treatment is a different risk proposition than permanent hearing loss. Patients who were not counseled about the possibility of permanent auditory damage cannot have provided genuinely informed consent for their infusions.
MDL Status and 2026 Litigation Update
The Tepezza cases were consolidated into an MDL in the Northern District of Illinois (Chicago) in October 2022. As of mid-2026, the MDL is in active pre-trial proceedings including expert witness development, Daubert briefing, and bellwether case selection. Horizon Therapeutics was acquired by Amgen in 2023 for $27.8 billion, making Amgen the primary defendant and significantly deepening the financial resources available for both litigation and eventual settlement. Plaintiff attorneys characterize the deep-pocket successor defendant as increasing ultimate settlement prospects. Related: other pharmaceutical company failure-to-warn cases.
Who Qualifies for a Tepezza Hearing Loss Claim?
You may qualify if you received one or more Tepezza infusions for thyroid eye disease and subsequently experienced hearing loss, tinnitus (ringing in the ears), or auditory processing difficulties. The strongest cases involve: multiple infusion courses, audiological testing confirming objective hearing loss at specific frequencies, onset of symptoms during or shortly after infusion treatment, and exclusion of other causes of hearing loss through medical workup. Tepezza infusion records, audiology reports before and after treatment, and treating physician records are the primary documentation needed.
How to File a Claim or Get Help
If you believe you qualify based on the eligibility criteria outlined above, the next step is a free consultation with an experienced attorney who handles this case type. Most plaintiff-side attorneys offer no-cost initial evaluations and work on contingency, meaning you pay nothing unless your case results in a recovery. Bring any relevant documentation to your consultation: receipts, medical records, correspondence, or any evidence of the harm you experienced.
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Tepezza Class Action Lawsuit: Your Legal Rights Explained: Frequently Asked Questions
Answers to the most common questions about this case and your legal options.
How common is hearing loss from Tepezza?
Published clinical studies have reported hearing-related adverse events in 50-65% of Tepezza patients in some cohorts. Tepezza's own clinical trials reported lower rates, but post-market real-world evidence and independent research has documented substantially higher adverse event frequencies. The discrepancy between trial data and real-world experience is central to the litigation's failure-to-warn theory.
Is the hearing loss from Tepezza permanent?
Some patients experience hearing improvements after completing Tepezza treatment; others have reported persistent or worsening hearing loss after infusions ended. The available evidence suggests a meaningful proportion of affected patients have permanent or long-lasting auditory damage. This uncertainty about reversibility is itself an alleged failure of informed consent disclosure.
Who makes Tepezza?
Tepezza was developed and originally marketed by Horizon Therapeutics. In 2023, Amgen acquired Horizon for $27.8 billion and assumed all legal and regulatory obligations associated with Tepezza. Amgen is the primary defendant in the ongoing MDL litigation.
I only had one Tepezza infusion, can I still file a claim?
Auditory adverse events have been reported after as few as one or two infusions. While longer infusion courses and higher cumulative doses are associated with greater risk, patients who experienced measurable hearing changes following a single infusion may have viable claims depending on the severity and documentation of the hearing impact.
How do I document hearing loss for a Tepezza lawsuit?
Essential documentation includes: Tepezza infusion records (facility records showing infusion dates, doses, and treating physician), pre-treatment audiology baseline testing if available, post-treatment audiology testing confirming hearing changes, and your treating physician's documentation of the hearing-related adverse event. If you don't have a pre-treatment baseline, post-treatment testing alone can still support a claim with appropriate expert analysis.
Legal Disclaimer
This article is for general informational purposes only and does not constitute legal advice or create an attorney-client relationship. Lawsuit eligibility, settlement amounts, and case status are subject to change as litigation develops. Always consult a licensed attorney in your jurisdiction before making legal decisions. LawsuitWatch is an independent journalism publication and is not a law firm. LawsuitWatch may receive referral compensation from affiliated legal service providers, which does not influence editorial content.