A consolidation of lawsuits filed in federal courts involving personal injury claims caused by the drug Tepezza (teprotumumab) has been approved for multidistrict litigation (MDL) in the Northern District of Illinois. The Tepezza MDL, presided over by Judge Thomas M. Durkin of Chicago, focuses on hearing loss or tinnitus that plaintiffs claim was caused as a direct result of taking Tepezza, made by the Irish pharmaceutical company Horizon Therapeutics. 

The first FDA-approved drug for a rare autoimmune disorder called Thyroid Eye Disease (TED), which can permanently impair vision, Tepezza received FDA approval in Jan. 2020 and works by blocking insulin-like growth factor 1 receptor (IGF-1R), which is believed to play a role in the development of TED. Administered intravenously over three to six months, Tepezza has been shown to improve symptoms of TED, such as double vision, pain or discomfort in the eyes, and bulging.  

Despite the assertion by Horizon Therapeutics that there weren’t enough cases pending, the Tepezza MDL was approved on June 5, and late last month, Judge Durkin held the first status conference with both parties. To date, at least 34 Tepezza lawsuits have been consolidated into the MDL. 

One of the most recent Tepezza lawsuits was filed in late May in an Ohio federal court. The plaintiff, who has permanent hearing loss, allegedly because of Tepezza, received infusions of the drug over a six-month period in 2021 and alleges that Horizon Therapeutics failed to notify the plaintiff and their physicians of the risk of hearing damage with Tepezza. 

The number of Tepezza lawsuits filed increased after a 2022 study published in the American Journal of Ophthalmology revealed that 22 out of 27 Tepezza patients developed hearing damage after a mean of fewer than 4 infusions of the drug. 

Horizon Therapeutics alerted the FDA to the fact that Tepezza carried with it a low risk of hearing loss or tinnitus before its approval, estimating that only 10% of users would be affected and that the side effects were only temporary. Plaintiffs allege that Horizon grossly understated the risk of hearing damage associated with Tepezza.