Tepezza Lawsuit: Hearing Loss Claims and MDL Status (2026)

One day after Judge Weisman granted plaintiffs' unopposed request to extend CMO 4, Judge Durkin reset the bellwether trial calendar. Trial one moved to June 8, 2026. The second, third, and fourth trials were set for August 3, then September 28, then November 30 of that year. CMO 4 sets the deadlines for fact discovery, experts, summary judgment, and Rule 702 briefing (fights over whether expert testimony can be used).

Horizon wanted Stacy Welch's case thrown out for the same Michigan-law reason that ended Cherl Merriweather's bellwether case. Judge Durkin denied that request and gave Welch until June 11, 2025, to amend. She moved from Michigan to Florida in October 2024 and is now treated there for hearing loss, facts that could affect which state's law governs her claims.

Judge Weisman denied plaintiffs' motion to make Horizon present six PALs (patient access liaisons) plus another sales representative for depositions. Plaintiffs said the PALs had dealt with the bellwether trial plaintiffs and their doctors.

Judge Weisman approved an unopposed change to the CMO 4 schedule. Corporate fact discovery would close May 9, 2025. Rule 702 motions were due September 15, 2025, and summary judgment motions in the four bellwether cases by December 5, 2025. The same day, Judge Durkin set new trial dates: the first on April 6, 2026, the last on September 21, 2026, and two more on June 1 and July 27.

In January, Judge Durkin had held back part of Horizon's challenge to the fraudulent misrepresentation claims for more briefing on preemption under the Supreme Court's Buckman decision. On January 28, both sides agreed to take up that issue at summary judgment instead. So the court denied that part of the motion without prejudice, meaning Horizon can raise it again later.

After a January 28 bellwether-selection hearing, Judge Durkin picked the four Initial Bellwether Trial Cases under CMO 3: Peter Chryssos, Consuelo Egger, Sara Meilleur, and Gloria Pledger. By February 11, 2025, the parties had to agree on the order of trials or each explain the order it preferred.

Ruling on Horizon's Rule 12 motions in the bellwether discovery cases, Judge Durkin denied the bid to dismiss the failure-to-warn claims and granted the motion against the design defect claims. The fraudulent misrepresentation motion was split: partly granted, partly denied, and partly continued for more briefing. Plaintiff Geri Kanesta-Rychner's request to file a second amended complaint was denied.

Horizon and the plaintiffs each asked the court to sanction the other over deposition problems. Judge Weisman refused to award sanctions to either party, finding both at fault. He said he did not want to push the lawyers toward sanction requests instead of working out disputes cooperatively and professionally.

After an October 31 hearing, Judge Weisman issued an order finding that defense counsel's objections at the deposition of Nicole Potthast were obstructionist and not well-founded. The judge also warned plaintiffs' leadership to use deposition time productively and to schedule depositions together, and said he leaned toward having plaintiffs repay Horizon's conference room costs for depositions cancelled at the last minute.

Judge Durkin dismissed Cherl Merriweather's complaint, one of the Initial Bellwether Discovery Cases. He held that Michigan law governed her claims, and the Michigan statute in force at the time barred product liability suits against makers of FDA-approved drugs. Michigan repealed that statute in February 2024. Horizon was not allowed to pick a replacement, so eleven discovery cases remained.

Judge Weisman cancelled an August 6 status hearing after a joint report showed the two sides had agreed on how many depositions of Horizon's current and former employees may be taken. The deal splits them into two windows: up to February 14, 2025, and from that date through April 10, 2025.

Horizon filed four Rule 12(b)(6) motions, which argue that claims fail as a matter of law even if the facts alleged are true. They targeted nine bellwether complaints, design defect claims in eleven complaints, fraudulent misrepresentation claims in five complaints, and every claim by Cherl Merriweather.

Judge Weisman entered Case Management Order No. 4, which sets deadlines for core and supplemental fact discovery, expert discovery, summary judgment, and Rule 702 briefing on expert testimony. The order also called for court-ordered mediation to begin around August 1, 2024, and repeat every 90 days, and set bellwether trials for March 9, May 4, June 29, and August 24, 2026. He also entered Case Management Order No. 5, which lays out the rules for taking depositions.

Judge Durkin signed an order identifying the Initial Bellwether Discovery Cases. Under CMO 3, the pool holds twelve cases: four chosen by plaintiffs, four by Horizon, and four at random. These cases go through Rule 12 motions and case-specific discovery before four are picked for trial.

After oral argument, Judge Durkin ruled that the first bellwether trial will begin on March 9, 2026. He gave the parties until May 10, 2024, to file an agreed proposed schedule, or a side-by-side comparison of their competing schedules if they could not agree.

Judge Durkin granted Horizon's motion to amend CMO 3 and pushed the deadline to select the Initial Bellwether Discovery Cases to May 30, 2024. He added that no more extensions of this deadline would be granted.

Horizon asked to delay the January 9, 2024, status hearing, and plaintiffs' leadership objected. Judge Weisman denied Horizon's request, explaining that status hearings are an important tool for managing discovery, especially in a case where discovery had been slow to gain traction.

At an in-person discovery conference, Judge Weisman capped any ESI protocol at 65 custodians. ESI means electronically stored information, and custodians are the people whose files get searched. Plaintiffs may later ask, with court approval, to add more. The judge also told plaintiffs' leadership to instruct all plaintiffs' lawyers that their clients must preserve their own ESI.

Using Cynthia Williams's case as a test, Judge Durkin held that preemption does not bar her design defect theory for the period before FDA approval. That lets her argue Horizon should have submitted a safer drug to the FDA. Her post-approval design defect claims were dismissed. The court took no position on whether design defect claims fail for other reasons.

Judge Durkin entered Case Management Order No. 3. It sets up a twelve-case discovery pool (four plaintiff picks due in 60 days, four Horizon picks due in 90 days, and four random picks), later narrowed to four trial cases. It also requires each plaintiff to serve a Plaintiff Profile Form, signed authorizations, and medical records within 30 days.

Amgen announced that it closed its purchase of Horizon Therapeutics plc for $116.50 per share in cash, a deal with an equity value of about $27.8 billion. Tepezza was one of the Horizon medicines Amgen added to its portfolio.

At a status hearing, Judge Durkin sent the MDL to Magistrate Judge M. David Weisman for discovery supervision, with full power to adjust the discovery deadline, and to handle settlement conferences. He also set oral argument on the design defect question in the Williams case for September 29, 2023.

The FDA approved Horizon's label supplement, first submitted January 20, 2023, adding to the Warnings and Precautions, Adverse Reactions, and Patient Counseling sections. The updated label states Tepezza may cause severe hearing impairment, sometimes permanent, and tells doctors to assess hearing before treatment starts, while it is given, and after it ends.

At the initial status hearing, Judge Durkin granted the unopposed motion to name plaintiffs' co-lead counsel, executive committee, and liaison counsel, and signed the order the next day. Horizon told the SEC the court also vacated earlier deadlines in individual cases and told the parties to confer on a single procedure for its preemption-based motions to dismiss.

Judge Durkin's first case management order consolidated all transferred and future Tepezza cases for pretrial purposes under master case number 1:23-cv-03568. It does not mean the cases will be tried together. It also set a June 28, 2023, hearing where the court planned to discuss how to appoint lawyers to lead the plaintiffs' side.

Plaintiff Kimberly Exton had proposed a California venue, and Horizon opposed an MDL. The JPML instead moved the federal Tepezza cases to federal court in northern Illinois (N.D. Ill.), where Horizon is based, and assigned them to Judge Thomas M. Durkin. The panel counted 37 cases in eight districts and said one judge should resolve the shared preemption and Daubert (expert evidence) challenges.

The FDA approved a label supplement that revised the Indications and Usage section of Tepezza's prescribing information. The new label says the drug treats thyroid eye disease regardless of how active the disease is or how long a patient has had it. Horizon submitted the request on March 23, 2023.

Daniel Weibel asked the court to relate the Tepezza cases pending in Illinois federal court (N.D. Ill.) and reassign them to a single judge, citing Local Rule 40.4 and Internal Operating Procedure 13(e). The JPML later described this as a request for a docket that would resemble an intra-district MDL. Horizon filed its opposition on January 13, 2023.

Horizon asked the court to dismiss Daniel Weibel's complaint. After Weibel amended his complaint on November 28, the court let Horizon withdraw that motion, and Horizon filed a new motion to dismiss the amended complaint on January 9, 2023.

Daniel Weibel filed a complaint against Horizon in Illinois federal court (N.D. Ill.). Horizon later told the SEC that starting in the third quarter of 2022, it was served with several complaints from people who said they took Tepezza, suffered hearing impairment, and were not properly informed of that risk.