Judge Strikes Some Claims and Plaintiffs’ Experts in Ozempic Lawsuits: A Pivotal Development in GLP-1 Litigation
In a significant ruling on August 18, 2025, a Pennsylvania federal judge overseeing the multidistrict litigation (MDL) involving Ozempic and other glucagon-like peptide-1 receptor agonists (GLP-1 RAs) struck several claims and disqualified two plaintiffs’ expert witnesses, reshaping the trajectory of this high-stakes pharmaceutical litigation. The MDL, centralized in the Eastern District of Pennsylvania under U.S. District Judge Karen S. Marston, encompasses over 2,190 lawsuits against Novo Nordisk and Eli Lilly, alleging that their blockbuster drugs—Ozempic, Wegovy, Rybelsus, Mounjaro, and Trulicity—caused severe side effects, including gastroparesis, intestinal blockages, and non-arteritic anterior ischemic optic neuropathy (NAION). This article examines the ruling’s details, its implications for plaintiffs and defendants, the broader context of the litigation, and what lies ahead for the thousands of affected patients in the United States.
The Ruling: Striking Claims and Expert Testimony
On August 18, 2025, Judge Marston issued a pivotal order in MDL 3094, dismissing several claims from the plaintiffs’ master complaint and striking two expert witnesses whose testimony was deemed unreliable under Federal Rule of Evidence 702. The master complaint, filed by plaintiffs’ counsel, alleged a range of claims, including failure to warn, defective design, breach of warranty, fraud, negligence, and consumer protection violations. The judge’s decision to pare down the complaint focused on claims deemed insufficiently supported or preempted by federal law, particularly those related to the adequacy of FDA-approved warning labels.
The dismissal of two plaintiffs’ experts is particularly significant. These experts were expected to testify on general causation, linking GLP-1 drugs to conditions like gastroparesis and NAION. The defense, represented by firms like DLA Piper for Novo Nordisk and Kirkland & Ellis for Eli Lilly, argued that the experts’ methodologies lacked scientific rigor, relying too heavily on clinical observations rather than objective diagnostic tests like gastric emptying studies for gastroparesis. Judge Marston agreed, finding that the experts’ opinions did not meet the Daubert standard for admissibility, which requires that expert testimony be based on reliable scientific methods and principles. This ruling could limit the scope of evidence plaintiffs can present, particularly for gastroparesis claims, which form the core of the MDL.
While specific claims were dismissed, the court allowed failure-to-warn claims to proceed, acknowledging that plaintiffs had sufficiently alleged that Novo Nordisk and Eli Lilly failed to adequately disclose risks despite evidence from adverse event reports and clinical studies. This partial victory keeps the litigation alive but narrows its focus, forcing plaintiffs to refine their arguments around warning label deficiencies.
Background of the Ozempic MDL
The Ozempic lawsuits, consolidated into MDL 3094 in February 2024, stem from allegations that GLP-1 receptor agonists, used for type 2 diabetes and weight loss, cause severe side effects not adequately disclosed to patients or physicians. As of August 1, 2025, the MDL includes 2,190 cases, with plaintiffs claiming injuries such as gastroparesis (stomach paralysis), ileus, bowel obstruction, NAION (leading to vision loss), and other complications like pancreatitis and gallbladder disease. The litigation has grown rapidly, with nearly 200 new cases filed in July 2025 alone, and legal analysts predict the total could reach 10,000.
Plaintiffs argue that manufacturers Novo Nordisk and Eli Lilly knew or should have known about these risks but failed to update warning labels or inform the medical community adequately. For instance, a Harvard study in July 2024 linked semaglutide (the active ingredient in Ozempic, Wegovy, and Rybelsus) to a significantly increased risk of NAION, prompting further scrutiny by the FDA and the Danish Medicines Agency. Gastroparesis claims have been contentious, with defendants insisting that only objective diagnostic tests, like gastric emptying studies, should confirm the condition—a standard plaintiffs’ counsel argues is overly restrictive, as many diagnoses rely on clinical judgment.
The MDL, initially overseen by Judge Gene E.K. Pratter, transitioned to Judge Marston following Pratter’s passing in May 2024. The litigation is in the discovery phase, with key deadlines set for fact discovery (July 2, 2025) and expert reports (November 18, 2024, for plaintiffs; December 23, 2024, for defendants). A critical Rule 702 (Daubert) hearing scheduled for May 14, 2025, will further evaluate the admissibility of expert testimony, potentially shaping the litigation’s outcome.
Implications for Plaintiffs
The dismissal of claims and expert witnesses poses significant challenges for plaintiffs. By striking two experts, Judge Marston has weakened the plaintiffs’ ability to establish general causation, a cornerstone of product liability cases. Without admissible expert testimony, plaintiffs may struggle to prove that GLP-1 drugs directly caused their injuries, particularly for gastroparesis, which relies heavily on expert analysis to link symptoms to the drug. This ruling could lead to the dismissal of cases lacking objective diagnostic evidence, potentially reducing the MDL’s scope.
However, the survival of failure-to-warn claims offers a lifeline. Plaintiffs can still argue that Novo Nordisk and Eli Lilly understated risks on FDA-approved labels, a claim bolstered by nearly 500 reported deaths linked to semaglutide in the FDA’s Adverse Event Reporting System. The plaintiffs’ leadership, including firms like Motley Rice and Seeger Weiss, is likely to focus on strengthening these claims through discovery, seeking internal company documents to demonstrate what manufacturers knew about risks and when.
The ruling also highlights the importance of plaintiff fact sheets, which document medical histories and prescription timelines. Accurate and detailed documentation will be critical, as courts emphasize objective evidence. Attorneys are advising clients to secure medical records, specialist visits, and timelines linking symptoms to drug use to bolster credibility.
Implications for Defendants
For Novo Nordisk and Eli Lilly, the ruling is a partial victory. Striking expert testimony and dismissing certain claims strengthens their defense by narrowing the litigation’s focus to warning label adequacy, where they can argue that FDA-approved labels disclosed sufficient risks. The defendants’ push for objective diagnostic standards, like gastric emptying tests, aligns with their strategy to limit the number of viable claims, as many plaintiffs rely on symptom-based diagnoses.
However, the persistence of failure-to-warn claims keeps the pressure on. Discovery into the companies’ internal safety data and marketing practices could uncover evidence of negligence or intentional omissions, potentially increasing liability. The growing number of NAION-related claims, supported by recent studies, adds another layer of complexity, as vision loss is a particularly severe and sympathetic injury that could sway juries.
Broader Context: Trends in Pharmaceutical Litigation
The Ozempic MDL reflects broader trends in pharmaceutical litigation, where plaintiffs target blockbuster drugs for undisclosed side effects. Similar cases, like those involving Zantac or Vioxx, have hinged on expert testimony and warning label disputes. The emphasis on objective diagnostics in this case mirrors defense strategies in other MDLs, where manufacturers seek to raise the evidentiary bar to disqualify claims.
The litigation also underscores the tension between regulatory approval and post-market surveillance. While GLP-1 drugs were rigorously tested for FDA approval, adverse event reports have prompted scrutiny of whether manufacturers adequately updated warnings as new risks emerged. The FDA’s ongoing investigation into side effects like hair loss, suicidal thoughts, and intraoperative pulmonary aspiration further complicates the landscape, potentially fueling additional claims.
What’s Next: Bellwether Trials and Potential Settlements
The MDL is moving toward bellwether trials, expected to begin in early 2026, which will test the strength of both sides’ arguments. These representative cases will influence settlement negotiations, as favorable plaintiff verdicts could pressure Novo Nordisk and Eli Lilly to resolve claims globally. Legal analysts estimate potential liability exceeding $2 billion, driven by the volume of claims, the severity of injuries, and the possibility of punitive damages for alleged corporate misconduct.
The May 14, 2025, Daubert hearing will be a critical milestone. If plaintiffs can introduce new, admissible expert testimony, they may regain ground lost in the recent ruling. Conversely, further exclusions could lead to dismissals of entire injury categories, such as gastroparesis. The plaintiffs’ leadership is also pushing for a separate “Vision Injury Track” to streamline NAION claims, which could accelerate resolution for those cases.
Legal and Practical Considerations
For plaintiffs considering joining the MDL, timely action is crucial due to varying state statutes of limitations (typically 1–3 years from injury or discovery). Legal representation from firms experienced in MDL 3094, such as Morgan & Morgan or TorHoerman Law, is recommended to navigate complex fact sheets and discovery protocols. Compensation may cover medical expenses, lost wages, pain and suffering, and, in some cases, punitive damages.
For the legal profession, the ruling highlights the importance of robust expert testimony in mass torts. Firms must invest in scientifically rigorous experts to withstand Daubert challenges, a lesson applicable beyond pharmaceutical cases. The MDL’s structure, with its Common Benefit Fund to distribute litigation costs, also underscores the collaborative nature of such cases, requiring coordination among dozens of law firms.
Conclusion: A Shifting Battlefield
Judge Marston’s August 2025 ruling marks a turning point in the Ozempic MDL, narrowing the scope of claims and raising the bar for expert testimony. While plaintiffs face hurdles in proving causation, the survival of failure-to-warn claims keeps the litigation viable, with discovery poised to uncover critical evidence. As the MDL progresses toward bellwether trials, the outcome will shape not only the fate of thousands of plaintiffs but also the broader landscape of pharmaceutical accountability in the United States. Patients, attorneys, and manufacturers alike await the next developments, with billions in potential liability hanging in the balance.