As of April 2025, the Tepezza hearing loss litigation has reached 213 pending cases in the federal multidistrict litigation (MDL), with bellwether trials scheduled to begin in 2026. This litigation centers around allegations that Horizon Therapeutics (now owned by Amgen) failed to adequately warn patients and healthcare providers about the risk of permanent hearing loss and other auditory side effects associated with Tepezza, the first FDA-approved treatment for thyroid eye disease (TED).
In this blog, the dangerous drug attorneys at Wisner Baum provide an update on the litigation, highlighting the latest developments, ongoing court proceedings, and the background on why people are filing Tepezza lawsuits.
Current Status of Tepezza Litigation
The Tepezza hearing loss MDL, overseen by Judge Thomas M. Durkin in the Northern District of Illinois, is progressing through the discovery phase. Both the plaintiffs and Horizon Therapeutics are gathering evidence and preparing their cases ahead of the upcoming bellwether trials. These initial trials will play a pivotal role in shaping the course of future litigation and could influence settlement talks.
Bellwether trials have been set for March 2026, with the first trial scheduled to begin on March 9, 2026. Additional trials are planned for later in the year:
- First Bellwether Trial: March 9, 2026
- Second Bellwether Trial: May 4, 2026
- Third Bellwether Trial: June 29, 2026
- Fourth Bellwether Trial: August 24, 2026
Each of these trials is expected to last 3-4 weeks, though the length may vary depending on the complexity of the cases. While the outcomes of these trials are not binding on other cases, they are likely to significantly influence settlement discussions and the overall direction of the litigation.
What is the Tepezza Hearing Loss Lawsuit About?
Tepezza (teprotumumab), the first FDA-approved medication for thyroid eye disease (TED), is named in lawsuits due to claims of undisclosed hearing-related side effects. Specifically, Tepezza lawsuits allege manufacturer, Horizon Therapeutics, failed to adequately warn patients and healthcare providers about the risks of hearing loss and other auditory side effects associated with the drug.
Approved by the FDA in January 2020, Tepezza was hailed as a breakthrough treatment for thyroid eye disease (TED), a condition frequently linked to Graves' disease. TED can cause painful eye bulging, vision loss, and other severe symptoms.
However, plaintiffs allege that despite mounting evidence linking Tepezza to hearing problems, Horizon continued to market the drug as safe and effective, without warning about the potential for irreversible hearing damage.
Key allegations in the lawsuits include:
- Failure to conduct adequate safety studies on the hearing-related side effects of Tepezza
- Failure to warn patients and healthcare providers about the risk of permanent hearing damage
- Misrepresentation of the hearing issues reported in clinical trials, which were described as temporary
- Delayed updates to the drug’s warning label, which only acknowledged the risk of hearing loss in July 2023 —more than three years after the drug’s approval.
What is the Scientific Evidence Against Tapezza?
The Tepezza litigation centers on research showing higher rates of hearing dysfunction than initially reported in clinical trials. While phase 2 and 3 trials indicated only 10% of patients experienced hearing issues, subsequent studies revealed a much higher incidence. A 2021 study found that 46% of patients treated with teprotumumab for thyroid eye disease reported hearing symptoms, such as autophony, ear plugging, or muffled hearing.
A 2022 prospective observational case study of 27 patients treated with teprotumumab for thyroid eye disease, 81.5% developed new otologic symptoms, most commonly after about four infusions. While symptoms like tinnitus and ear fullness usually resolved, only 45.5% of patients with subjective hearing loss experienced resolution, and sensorineural hearing loss was confirmed in most patients who underwent audiometric testing. This study explicitly concluded that “hearing loss is a concerning adverse event of teprotumumab, and its mechanism and reversibility should be further studied.”
More recent evidence from a 2024 study analyzing audiometric data confirmed that "teprotumumab influences hearing function, most significantly at higher frequencies and in older patients," further substantiating plaintiffs' claims. The research recommended audiometric testing before treatment to better counsel patients about risks.
Notable Lawsuits in the Tepezza Litigation
Several early cases have already played a significant role in shaping the direction of the Tepezza litigation:
- Daniel Weibel filed one of the first lawsuits in August 2022, claiming permanent hearing loss after receiving Tepezza infusions between June and September 2020.
- Norma Perez Diaz filed in February 2023, alleging both permanent hearing loss and tinnitus.
- Angela Simpson developed hearing loss and tinnitus after only a few months of treatment with Tepezza.
These cases have highlighted a troubling pattern, with plaintiffs consistently reporting severe hearing impairments following treatment with Tepezza for thyroid eye disease.
Tepezza Side Effects: What You Should Know
Tepezza has been associated with a range of side effects, with hearing-related issues emerging as particularly concerning. The most serious hearing-related side effects linked to Tepezza treatment include:
- Permanent hearing loss (sensorineural hearing loss)
- Tinnitus (ringing in the ears)
- Hypoacusis (reduced hearing ability)
- Autophony (hearing one’s own voice as too loud or echoing)
- Eustachian tube dysfunction
- Hyperacusis (increased sensitivity to certain sounds)
Many patients have reported that these hearing issues developed during or shortly after completing their Tepezza infusions, and in many cases, the damage appears to be permanent.
Common Non-Hearing Side Effects
In addition to hearing problems, Tepezza is associated with several other side effects, which include:
- Muscle spasms
- Nausea
- Hair loss (alopecia)
- Diarrhea
- Fatigue or weakness
- Hyperglycemia (high blood sugar)
- Dysgeusia (altered taste)
- Dry skin
- Headaches
- Nail disorders
- Infusion-related reactions
While some of these side effects may be temporary or manageable, they can still significantly impact a patient’s quality of life.
Potential Tepezza Settlement Values
As of now, no settlements have been reached in the Tepezza litigation. However, legal experts suggest that settlement values, if they occur, will be influenced by several key factors, including the severity of the alleged injuries, the strength of the evidence connecting Tepezza to the hearing damage, and the outcomes of the bellwether trials.
Some of the variables that could affect potential settlements include:
- The outcomes of the bellwether trials
- The severity of each plaintiff’s hearing loss
- The impact on a plaintiff’s quality of life and ability to work
- The strength of the causal connection between Tepezza and the hearing damage
- Horizon’s financial considerations and litigation strategy
Timeline of Key Events in the Tepezza Litigation
The Tepezza litigation has evolved rapidly from individual lawsuits to a consolidated MDL. Here’s a quick look at the major developments:
- January 2020: FDA approves Tepezza as the first treatment for thyroid eye disease (TED).
- 2020-2022: Patients report hearing issues following Tepezza infusions.
- August 2022: The first Tepezza lawsuit is filed by Daniel Weibel in Illinois.
- March 2023: Plaintiffs file a motion to transfer and consolidate cases in an MDL in California.
- June 2023: Judicial Panel on Multidistrict Litigation consolidates cases into an MDL under Judge Thomas M. Durkin in Chicago.
- July 2023: FDA updates Tepezza’s warning labels to acknowledge hearing-related side effects.
- April 2025: The MDL reaches 213 pending cases, with bellwether trials still scheduled to begin in 2026.
What Tepezza Patients Should Know
For those who have already received Tepezza infusions, it’s essential to be aware of the risks associated with hearing loss. Here’s what you should keep in mind:
Monitoring for Hearing Changes
If you have received Tepezza treatment, it’s crucial to monitor any changes in your hearing, such as:
- Difficulty hearing in noisy environments
- Ringing or buzzing sounds in the ears
- A sensation that sounds are muffled
- Increased sensitivity to certain sounds
- A feeling that your voice is louder or more echoing than normal
If you experience any of these symptoms, it’s important to consult with a healthcare provider.
Treatment Considerations
If you are considering Tepezza for TED treatment, discuss the potential risks with your healthcare provider. Important points to address include:
- The risk of hearing-related side effects
- Alternative treatments for thyroid eye disease
- The importance of baseline hearing assessments before starting treatment
- The need for regular hearing monitoring during and after treatment
- The high cost of Tepezza treatment, which can cost roughly $15,000 per vial, with up to eight infusions required.
Having a thorough understanding of the potential risks and benefits of Tepezza can help you make an informed decision regarding your treatment.
What’s Next in the Tepezza Hearing Lawsuits?
The Tepezza litigation is still evolving, with key milestones expected as the first bellwether trials approach in 2026. Our attorneys believe this litigation is poised to expand, especially as more scientific research continues to emerge connecting Tepezza to hearing loss.
For patients who have experienced hearing loss or other auditory side effects after Tepezza treatment, these lawsuits represent an important avenue to address the alleged failure to adequately warn about the serious risks linked to this FDA-approved treatment.
As the bellwether trials unfold and more cases are prepared for trial, the outcomes will likely have a profound impact on the direction of the litigation and may ultimately lead to settlements or further legal developments. Stay informed about the latest updates and speak with a knowledgeable attorney if you believe you have been affected by Tepezza.
