Tepezza for Thyroid Eye Disease: What Patients Were Told, and What the Research Found

What Thyroid Eye Disease Is

Thyroid eye disease (TED) — also called Graves' orbitopathy or Graves' eye disease — is an autoimmune condition in which the immune system attacks the tissue surrounding the eyes. The muscles and fat behind the eye become inflamed and expand inside the bony orbit, which has nowhere to give. The eye gets pushed forward.

Symptoms range widely:

Proptosis (exophthalmos) — bulging of one or both eyes, the most recognizable sign
Diplopia — double vision, present in the majority of patients in the clinical trials
Redness, swelling, and irritation of the eyes and eyelids
Dry eyes and gritty sensation
Pain with eye movement
Eyelid retraction, giving a wide-eyed or staring appearance
Light sensitivity
Blurred vision and difficulty moving the eyes
In severe cases, pressure on the optic nerve threatening vision

TED runs in two phases. The active phase — progressive inflammation and worsening symptoms — typically lasts six months to two years. It's followed by an inactive phase where things stop getting worse, though changes that occurred may persist.

TED is most often associated with Graves' disease, an autoimmune thyroid disorder, but can also appear in people with an underactive thyroid or normal thyroid function. It's worth noting that severe, vision-threatening TED is relatively uncommon — affecting roughly 3–5% of patients with the condition. Most TED is mild to moderate, and historically was managed with supportive care: lubricating drops, prism glasses, sunglasses, and corticosteroids in more significant cases, with surgery generally reserved for after the active phase.

That context matters. If a treatment carries a risk of permanent hearing damage, the calculus for a patient with mild-to-moderate disease is very different than for one facing vision loss — but that calculation is only possible if the patient is actually told about the risk.

What Tepezza Is and How It's Given

Tepezza (teprotumumab-trbw) was approved by the FDA in January 2020 as the first and only drug approved to treat thyroid eye disease. It was developed by Horizon Therapeutics; Amgen acquired Horizon in October 2023.

How it works. Tepezza is a monoclonal antibody that binds and blocks the insulin-like growth factor-1 receptor (IGF-1R). In TED, that receptor is over-expressed on orbital fibroblasts and appears central to the inflammatory process driving tissue expansion. Blocking it interrupts the cascade.

The treatment course:

Given intravenously — infusion center, hospital, physician's office, or sometimes at home
8 infusions total, one every 3 weeks
First infusion: 10 mg/kg; the remaining seven: 20 mg/kg
Each infusion runs 60 to 90 minutes
Total course: approximately 5 months

How well it works. In the pivotal trials, 82% of Tepezza patients showed significant reduction in proptosis compared to 10% on placebo, and about 69% saw improvement in double vision. Many patients noticed change after two or three infusions. For people who had spent years with visible, painful, disfiguring symptoms and no real treatment option, this was genuinely meaningful — which is part of why the hearing risk disclosure question matters so much. Patients weren't being asked to weigh a trivial benefit.

Other Known Side Effects

Beyond the hearing issues discussed below, Tepezza is associated with:

Muscle spasms
Nausea and diarrhea
Fatigue
Hair loss and dry skin
Headache
Altered taste — often described as a metallic or "off" flavor
Elevated blood glucose — clinically significant for diabetic and pre-diabetic patients; the label directs assessment before and monitoring during treatment
Swelling, particularly in the hands and feet
Elevated blood pressure
Infusion reactions during or within 24 hours of an infusion
Menstrual irregularities — reported in roughly 23% of menstruating women in the trials, compared to about 4% on placebo
Serious risk of fetal harm; pregnancy must be avoided during and after treatment

The Hearing Risk

What the label said when Tepezza launched

Tepezza's original prescribing information reported hearing-related adverse events in about 10% of patients in the two pre-approval clinical trials — trials in which only 84 patients actually received the drug. The effects listed included deafness, eustachian tube dysfunction, hyperacusis, hypoacusis, and autophony, and the company characterized them as generally temporary, resolving after treatment ended.

Nothing on the label warned of permanent hearing loss. Nothing recommended a baseline hearing test. Nothing instructed physicians to monitor hearing during treatment.

What researchers found once the drug was in real-world use

65%. Stanford researchers presented findings at the Endocrine Society's ENDO 2021 conference: among 26 patients who received at least four infusions, 17 developed hearing symptoms. Six reported hearing loss, seven developed tinnitus, three reported ear-plugging sensation, and roughly 29% developed autophony — hearing their own voice unnaturally loud. Symptoms typically emerged after an average of about 3.6 infusions, less than halfway through a standard course. The researchers recommended baseline audiogram testing before treatment.

Permanent cases documented. A 2021 case report in The Annals of Otology, Rhinology, and Laryngology described a 61-year-old woman with Graves' disease who developed bilateral hearing loss, sound distortion, and tinnitus. Treatment was stopped and corticosteroids given. Four months later, no improvement. The authors described it as one of the first documented cases of irreversible sensorineural hearing loss following teprotumumab treatment.

The recovery data. A 2022 study in the American Journal of Ophthalmology followed patients eight months past their final infusion. Among those who had developed subjective hearing loss or decreased word comprehension, only 45.5% had fully recovered. About 20% still had autophony; nearly 10% still had ear-plugging symptoms.

A dose relationship. A Stanford case study reported a patient who developed significant bilateral hearing loss on a full-dose course, recovered after stopping, and then tolerated a much lower dose a year later without the same effect — evidence of a dose-dependent relationship.

Why the mechanism makes sense

The receptor Tepezza blocks, IGF-1R, is also essential to the inner ear. IGF-1 signaling supports the survival and repair of cochlear hair cells — the sensory cells that convert sound into nerve signals. The connection between IGF-1 deficiency and sensorineural hearing loss was documented in the medical literature well before Tepezza existed.

Cochlear hair cells in humans do not regenerate. Once damaged, they stay damaged. Researchers publishing case reports in 2021 proposed exactly this pathway as the mechanism behind the hearing loss they were observing.

The label change — July 2023

On July 17, 2023, three and a half years after approval, the FDA approved an updated Tepezza label adding to the Warnings and Precautions section that the drug may cause severe hearing impairment including hearing loss that may in some cases be permanent, and directing physicians to assess patients' hearing before, during, and after treatment.

Patients treated before that date received their infusions without any of that information.

If You Received Tepezza: What to Watch For

Worth documenting and discussing with an audiologist:

Trouble following conversation, especially in noisy environments
Ringing, buzzing, roaring, or humming in one or both ears
A persistent plugged or full feeling in the ears
Your own voice sounding unusually loud, hollow, or echoing
Muffled, distant, or distorted sound
Clicking or popping
New sensitivity to ordinary sound levels
Dizziness or balance changes

If you're currently in treatment and notice hearing changes, tell your doctor. Treatment decisions belong between you and your physician — always, and regardless of any legal question.

If you can get an audiogram, get one. It matters for your medical care first: documented hearing loss opens the door to hearing aids, assistive devices, and tinnitus management. It also creates a record.

Where the Legal Situation Stands

More than 275 lawsuits are pending in a federal multidistrict litigation in the Northern District of Illinois, alleging Horizon failed to warn patients and physicians about the risk of permanent hearing damage. Court filings allege the company held internal data showing hearing-related adverse events in up to 40% of patients as early as March 2020 — and that a physician who pressed internally for disclosure was terminated.

Trial deadlines in the litigation have been suspended while the parties conduct court-supervised settlement negotiations. New cases are still being accepted.

If you received Tepezza infusions and developed hearing loss or tinnitus, a free case review will tell you where you stand.

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ATTORNEY ADVERTISING. This page is informational and is not medical or legal advice. Do not start, stop, or change any treatment based on information here — talk to your physician. Allegations described are from pending litigation and have not been proven.