Lawsuit alleges teprotumumab-trbw from Horizon Therapeutics caused permanent hearing loss

A total of 18 similar lawsuits have been filed in 5 different U.S. District Courts. (Image Credit: AdobeStock/WESTOCK)

A Pennsylvania woman is the latest person to file a product liability lawsuit against Horizon Therapeutics, claiming teprotumumab-trbw (Tepezza, Horizon Therapeutics) infusions caused permanent hearing loss.

The lawsuit was filed this month in U.S. District Court for the Northern District of Illinois by Debora Welch Klostermann, alleging Horizon failed to adequately warn people about the potential side effects following teprotumumab-trbw infusions.

According to court documents, a total of 18 similar lawsuits have been filed in 5 different U.S. District Courts, and Aboutlawsuits noted a motion was made in March to centralize the claims for pretrial hearings in a teprotumumab-trbw hearing loss multidistrict litigation (MDL) in the U.S. District Court for the Northern District of California. This would consolidate pretrial proceedings before one federal judge.

Klostermann is represented by Peiffer Wolf Carr Kane Conway & Wise LLP, with offices in Cleveland, Ohio, and Chicago. The filing seeks a jury trial.

“We do not believe the lawsuits have merit and intend to vigorously defend them,” Horizon said in a statement to Ophthalmology Times. “Hearing impairment was identified as a potential adverse event in the Tepezza pivotal clinical trials, was thoroughly discussed at the FDA advisory committee meeting prior to the approval of Tepezza and is referenced in the Tepezza product label.”

Horizon Therapeutics on April 14 announced the FDA had approved an update to the Indications and Usage section of the teprotumumab-trbw label to specify its use for the treatment of thyroid eye disease regardless of activity or duration.

Court documents indicate that Klostermann was diagnosed with thyroid eye disease and/or Graves’ disease and received teprotumumab-trbw infusions from a physician from July 2021 through December 2021.

In the lawsuit, Klostermann claims she took teprotumumab-trbw and suffered permanent hearing damage, and alleges Horizon Therapeutics should have known teprotumumab-trbw, when used as prescribed, could cause hearing loss, and other issues, including tinnitus.

The lawsuit further alleges that Horizon Therapeutics’ post-marketing research determined that teprotumumab-trbw could cause hearing loss, but it failed to inform potential users, prescribers, including ophthalmologists, or federal regulators about the potential risk.

“At all relevant times, the U.S. label for teprotumumab-trbw contained no warning of permanent hearing loss or tinnitus,” the lawsuit alleged.

The FDA in January of 2020 approved teprotumumab-trbw, making it the first approved drug indicated to treat TED. It inhibits the activity of the protein insulin-like growth factor-1 (IGF-1), which is believed to a play as significant role in the development of the disorder.

However, the lawsuit alleges Horizon failed to conduct tests to determine the mechanism of action of the drug and the filing also maintains the teprotumumab-trbw label admits not “formal pharmacodynamic studies have been conducted with teprotumumab-trbw.”

In addition to the lawsuits already filed, Aboutlawsuits noted a number of former teprotumumab-trbw users are reporting they also suffered hearing loss or tinnitus after taking the drug, with issues persisting after their last use of the medication.

According to court documents, the U.S. Judicial Panel on Multidistrict Litigation (JPML) is considering the motion to consolidate the teprotumumab-trbw lawsuits to one U.S. district court.

Aboutlawsuits noted the U.S. JPML is likely to hear oral arguments on the motion during an upcoming hearing session in Philadelphia, which is scheduled for May 25, 2023.

In August, Johnson Becker PLLC filed the first known lawsuit against the company, raising allegations alleging hearing loss.

The firm filed the lawsuit, in which David Weibel alleges his use of teprotumumab-trbw for thyroid eye disease was the cause of permanent hearing loss. Weibel's lawsuit alleges Horizon Pharmaceuticals failed to warn him or his doctors that the medication could cause hearing loss and/or tinnitus, according to the complaint in Weibel's lawsuit.