Audiology Meets Endocrinology: Building Causation Timelines in Tepezza Claims

Building a causation timeline in a Tepezza claim means placing the patient's hearing history and their Thyroid Eye Disease treatment on a single, cross-referenced chronology, so the temporal relationship between the infusions and any hearing change is clear to the qualified expert. That is harder than it sounds, because the two halves of the story live in two different specialties that almost never share a chart.

Tepezza (teprotumumab-trbw) is an infusion drug approved in 2020 to treat Thyroid Eye Disease (TED), an autoimmune condition tied to thyroid disease that affects the eyes. In July 2023, the FDA updated the prescribing information to warn about the potential for severe and possibly permanent hearing impairment, and to recommend that clinicians assess hearing before, during, and after treatment. The current litigation, consolidated as a federal multidistrict litigation (MDL) in the Northern District of Illinois, centers largely on the claim that patients were not adequately warned that the infusions could cause permanent hearing loss and severe tinnitus.

Source Credit: FDA Tepezza (teprotumumab-trbw) prescribing information updated July 2023 regarding potential severe and possibly permanent hearing impairment and hearing monitoring; In re: Tepezza Marketing, Sales Practices, and Products Liability Litigation, MDL No. 3079, U.S. District Court for the Northern District of Illinois (Judge Thomas M. Durkin), centralized by the JPML in June 2023, with several hundred cases pending and bellwether proceedings scheduled in 2026. Manufacturer Horizon Therapeutics was acquired by Amgen in 2023. This is active litigation; confirm the current docket, label, and case count before relying on these details.

For a plaintiff firm or an independent medical examiner (IME) working these files, the difficulty is not that the records are missing. It is that they are scattered, and that hearing loss is common in the general population. Proving the sequence starts with getting the timeline right.

Why causation is the hard part in a Tepezza claim

Causation is contested in Tepezza claims because hearing loss and tinnitus have many possible causes, and the population that receives Tepezza is not young. Ototoxicity, meaning hearing or balance damage caused by a drug, has to be distinguished from hearing decline that would have happened anyway. Age-related hearing loss, called presbycusis, is common and progressive. Prior noise exposure, ear disease, and other ototoxic medications can all leave a similar mark on an audiogram.

So the question the record has to answer is a timeline question. What did the patient's hearing look like before the first infusion, what changed after, and how does that change line up with the doses? A retained audiologist or otolaryngologist can only address that if the before, the during, and the after are documented and placed side by side. When they are scattered across years of unconnected charts, the picture is easy to miss.

The records a Tepezza causation timeline needs

A usable Tepezza chronology pulls from at least three record sources, and the value is in cross-referencing them rather than summarizing each on its own.

• The audiology and ENT record. Audiograms (the hearing test that plots thresholds by frequency), tympanometry, and otolaryngology notes, including any documentation of tinnitus, autophony, or a patulous eustachian tube, and critically any audiogram from before treatment began.
• The endocrinology and ophthalmology record. The Thyroid Eye Disease diagnosis and course, thyroid labs, and the Tepezza infusion log: the dates, the number of infusions, and the dose of each.
• The primary care and medication history. The longitudinal record that shows prior hearing complaints, noise exposure, ear disease, and any other ototoxic medications the patient received over the years.

Placed on one timeline, these three sources let the reader see the sequence: the hearing baseline, the first infusion, the reported onset of hearing change or tinnitus, and the follow-up audiograms. That sequence is the spine of the case. Our medical chronology service is built to reconstruct exactly this kind of multi-specialty timeline, and the underlying outsourced medical record review is what turns years of scattered pages into it.

Isolating the pre-existing picture from the post-infusion picture

The single most valuable thing a chronology can do in a Tepezza file is make the pre-existing hearing picture and the post-infusion hearing picture both visible, so the expert can compare them. This is where the brief's real question lives, and it is a documentation task before it is a medical opinion.

From the record review side, that means pulling every audiogram forward and arranging them in order, marking the date of each infusion against them, and flagging what sits in the background: the patient's age and any presbycusis already noted, documented noise exposure, prior ear disease, and other ototoxic drugs such as certain chemotherapy agents, aminoglycoside antibiotics, or loop diuretics. We do not decide which of these explains the hearing change. We make sure none of them is invisible when the audiologist or otolaryngologist forms an opinion, and when opposing counsel goes looking for an alternative cause.

Where these timelines break down

Most Tepezza timelines fail in one of three predictable places, and each is a records problem rather than a medical one.

The first is a missing baseline. If no audiogram was performed before the first infusion, the before-and-after comparison has a hole in it, and the chronology needs to say so plainly rather than imply a baseline that was never captured. Naming the gap early lets the legal team decide how to address it, sometimes by locating an older audiogram from an unrelated visit.

The second is a scattered infusion record. Infusions may be given at an outpatient center separate from the treating endocrinologist, so the dose dates live in yet another chart. If those dates are wrong or incomplete, every alignment built on top of them is off. Confirming the infusion log against more than one source matters here.

The third is the unflagged confounder. A prior noise-exposure history or an earlier course of an ototoxic drug, buried deep in a primary care file, changes how an expert reads the case. Missing it does not make the case stronger. It makes it fragile, because the other side will find it.

What a well-built Tepezza chronology looks like

A well-built Tepezza chronology reads as one story told from two specialties, with the hearing record and the treatment record locked to the same dates. A few things separate a strong one from a simple date list.

It keeps every audiogram in sequence and ties each to the infusion timeline, so the reader can see what changed and when. It defines the clinical terms, so a legal reader understands what a sensorineural loss or a shifted threshold means without a medical dictionary. It flags the gaps and the confounders openly, rather than presenting a tidy narrative that hides them. And it stops at the evidence, leaving the causation opinion to the retained expert and the case decisions to the attorney.

How experienced teams handle a Tepezza inventory

Teams that handle these files well treat the chronology as the foundation the expert opinion sits on, not as a summary produced at the end. They order the records early, they confirm the infusion log against more than one source, and they insist that the pre-infusion baseline and the confounders are addressed on the face of the timeline. When a firm is screening a large Tepezza inventory, that discipline is what keeps a strong claim from looking like a weak one and a weak claim from consuming months of expert time.

If you want to pressure-test a Tepezza chronology before it goes to your expert, these questions help.

Questions to ask about a Tepezza causation timeline

• Is there a documented pre-infusion audiogram, and if not, has that gap been flagged rather than assumed?
• Are all serial audiograms in sequence and tied to specific infusion dates and doses?
• Was the infusion log confirmed against more than one record source?
• Are age-related decline, prior noise exposure, and other ototoxic medications flagged on the timeline?
• Is the reported onset of hearing loss or tinnitus pinned to a date the records actually support?
• Does the chronology stop at the evidence, leaving causation to the retained audiologist or otolaryngologist?

The bottom line for Tepezza claims

A Tepezza claim rises or falls on a timeline that most charts do not present on their own: the hearing record and the Thyroid Eye Disease treatment record, read against each other, with the baseline established and the confounders in view. Building that causation timeline is documentation work, and it is the work that lets the retained expert and the attorney do theirs on solid ground.

If you are screening or working a Tepezza inventory, the first practical step is to get the audiology and endocrinology records onto one cross-referenced chronology. We organize and flag the evidence. The audiologist, the otolaryngologist, and the attorney draw the conclusions. To scope a Tepezza matter, talk with our medical chronology team or start with a short pilot.

Source Credit: Tepezza label and litigation details are from the FDA prescribing information (updated July 2023) and public MDL No. 3079 dockets and reporting, and are subject to change; confirm the current status before relying on them. LezDo TechMed service figures are published company benchmarks and are scope-dependent, not per-case guarantees. LezDo TechMed organizes documented medical information for review by the appropriate qualified legal, medical, insurance, or claims professional and does not diagnose, determine causation, or opine on liability.