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Pharmaceutical
9 min read
Areas of Expertise :
Pharmaceutical, Gastroenterology, Ophthalmology, Pharmacology, Epidemiology
Published Date:
Last Modified Date:
Jurisdiction:
Federal. Third Circuit
Federal product liability claims involving Ozempic and other GLP-1 medications are proceeding through two multidistrict litigation dockets in the U.S. District Court for the Eastern District of Pennsylvania. MDL No. 3094 concerns alleged gastrointestinal injuries. The master complaint addresses eight medications: Ozempic, Wegovy, Rybelsus, Victoza, Saxenda, Trulicity, Mounjaro, and Zepbound. Plaintiffs allege conditions that include gastroparesis, ileus, intestinal obstruction or pseudo-obstruction, severe nausea and vomiting, gallbladder injuries, and other gastrointestinal problems. They also assert claims involving drug warnings, product design, marketing, warranties, and other state-law theories. Novo Nordisk and Eli Lilly dispute the allegations.
A separate proceeding, MDL No. 3163, covers lawsuits alleging non-arteritic anterior ischemic optic neuropathy, or NAION, following use of GLP-1 medications. The December 2025 transfer order initially concerned Ozempic, Wegovy, Saxenda, and Trulicity. By July 2026, the court described the NAION MDL as involving claims tied to Ozempic, Wegovy, Rybelsus, Saxenda, Trulicity, Mounjaro, and Zepbound. U.S. District Judge Karen S. Marston presides over both MDLs. In July 2026, the court authorized early discovery and motion practice in MDL 3163 on general causation and federal preemption/warning adequacy and directed the parties to propose deadlines for those proceedings.
The Judicial Panel on Multidistrict Litigation centralized 18 actions pending in 11 federal districts and noted 37 additional related actions pending in 15 districts. The cases involved Ozempic, Wegovy, Rybelsus, Trulicity, and Mounjaro and alleged gastroparesis, ileus, intestinal obstruction or pseudo-obstruction, and other gastrointestinal injuries. Plaintiffs also raised claims concerning what manufacturers knew about the alleged risks and whether patients and prescribing physicians received adequate warnings. The cases were transferred to the Eastern District of Pennsylvania as MDL No. 3094.
Early case management focused on legal and medical questions shared across the gastrointestinal cases. One issue concerned whether gastroparesis could be reliably diagnosed without objective gastric-emptying testing. Another addressed federal preemption and whether GLP-1 drug labels adequately warned about the gastrointestinal injuries alleged by plaintiffs. General causation later became part of the coordinated expert proceedings, addressing whether the medications are capable of causing the categories of injuries alleged in the MDL.
The FDA reported that labeling for GLP-1 receptor agonists was updated between October and November 2024 to include information about pulmonary aspiration during general anesthesia or deep sedation. The revisions affected sections addressing warnings and precautions, adverse reactions, and patient counseling. In November 2024, the FDA also required a postmarketing trial to examine temporary withholding of GLP-1 drugs, fasting duration, retained gastric contents, and delayed gastric emptying in connection with pulmonary aspiration risk. The labeling changes followed reports of pulmonary aspiration in patients taking GLP-1 medications who underwent procedures requiring general anesthesia or deep sedation.
A Rule 702 ruling issued by Judge Marston addressed the medical evidence used to establish a diagnosis of drug-induced gastroparesis. Plaintiffs offered opinions from Dr. Daniel L. Raines, a gastroenterologist, and Dr. Eliot L. Siegel, a radiologist with experience in nuclear medicine and diagnostic imaging. Defendants offered opinions from Dr. Linda A. Nguyen, a gastroenterologist. The court excluded the challenged opinions from Drs. Raines and Siegel and denied plaintiffs' partial motion concerning Dr. Nguyen.
Under the ruling, a plaintiff alleging drug-induced gastroparesis must have undergone a properly performed gastric-emptying study at the time of diagnosis that confirmed delayed gastric emptying. The court identified gastric-emptying scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test as accepted methods discussed in the record. Judge Marston also recognized that some plaintiffs would be unable to establish gastroparesis because their diagnoses were not supported by the required testing.
The court separately ruled that day on the defendants' motion to dismiss the master complaint. The motion was granted in part and denied in part across the claims presented in the consolidated pleading. Among other rulings, state-law design-defect claims were held preempted to the extent they would require manufacturers to change a GLP-1 drug's formula or dosage without prior FDA approval. Other pleaded theories remained, were narrowed, or could be amended under the court's decision.
The JPML created MDL No. 3163 for federal lawsuits alleging that certain GLP-1 drugs caused NAION. The litigation consisted of 21 actions pending in three districts, and the Panel had also been notified of nine related actions. The centralized cases at that stage involved Ozempic, Wegovy, Saxenda, and Trulicity. Plaintiffs asserted failure-to-warn, design-defect, and breach-of-warranty claims. The JPML identified common factual questions concerning product development, manufacture, testing, regulatory history, promotion, labeling, and the alleged capacity of the drugs to cause NAION. The Panel created a separate MDL rather than transferring the NAION cases into the existing gastrointestinal proceeding.
Judge Marston entered an order setting a Science Day for June 2, 2026. The order called for objective presentations covering diseases treated with GLP-1 medications, the drugs and their labeling and regulatory history, eye anatomy, NAION, and medical literature concerning GLP-1 drugs and the alleged injury. Presentations were limited to publicly available information and excluded discussion of individual plaintiffs and defendants' sales and marketing practices. Attorneys and experts were permitted to make the presentations.
Judge Marston granted the defendants' request for early discovery and motion practice on general causation and federal preemption/warning adequacy. The order described general causation as the question of whether the products are capable of causing the alleged injury, as distinct from whether a drug caused a particular person's condition. At that point, the court described the MDL as involving Ozempic, Wegovy, Rybelsus, Saxenda, Trulicity, Mounjaro, and Zepbound. The parties were directed to meet and confer on a proposed scheduling order for discovery and motion deadlines on the cross-cutting issues. They were also directed to develop a proposed schedule for plaintiff fact sheets and medical records documenting product use and diagnosis.
Judge Marston convened a Rule 702 evidentiary hearing beginning September 14, 2026, with proceedings scheduled through September 18. The hearing concerns Cross-Cutting Issues Nos. 2 and 3 in MDL 3094. Those proceedings address expert evidence associated with warning adequacy, federal preemption, and general causation for gastrointestinal injuries alleged in the litigation. Expert reports, depositions, briefing, and motions challenging proposed expert opinions preceded the hearing.
Court:
United States District Court for the Eastern District of Pennsylvania
Case Name:
In re: Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RAs) Products Liability Litigation
Drug Labels
Drug Regulation
Drug Research
Pharmacodynamics
Pharmacokinetics
Medical Research
Medical Imaging
Safety Warnings
Vision Loss
Federal product liability claims involving Ozempic and other GLP-1 medications are proceeding through two multidistrict litigation dockets in the U.S. District Court for the Eastern District of Pennsylvania. MDL No. 3094 concerns alleged gastrointestinal injuries. The master complaint addresses eight medications: Ozempic, Wegovy, Rybelsus, Victoza, Saxenda, Trulicity, Mounjaro, and Zepbound. Plaintiffs allege conditions that include gastroparesis, ileus, intestinal obstruction or pseudo-obstruction, severe nausea and vomiting, gallbladder injuries, and other gastrointestinal problems. They also assert claims involving drug warnings, product design, marketing, warranties, and other state-law theories. Novo Nordisk and Eli Lilly dispute the allegations.
A separate proceeding, MDL No. 3163, covers lawsuits alleging non-arteritic anterior ischemic optic neuropathy, or NAION, following use of GLP-1 medications. The December 2025 transfer order initially concerned Ozempic, Wegovy, Saxenda, and Trulicity. By July 2026, the court described the NAION MDL as involving claims tied to Ozempic, Wegovy, Rybelsus, Saxenda, Trulicity, Mounjaro, and Zepbound. U.S. District Judge Karen S. Marston presides over both MDLs. In July 2026, the court authorized early discovery and motion practice in MDL 3163 on general causation and federal preemption/warning adequacy and directed the parties to propose deadlines for those proceedings.
The Judicial Panel on Multidistrict Litigation centralized 18 actions pending in 11 federal districts and noted 37 additional related actions pending in 15 districts. The cases involved Ozempic, Wegovy, Rybelsus, Trulicity, and Mounjaro and alleged gastroparesis, ileus, intestinal obstruction or pseudo-obstruction, and other gastrointestinal injuries. Plaintiffs also raised claims concerning what manufacturers knew about the alleged risks and whether patients and prescribing physicians received adequate warnings. The cases were transferred to the Eastern District of Pennsylvania as MDL No. 3094.
Early case management focused on legal and medical questions shared across the gastrointestinal cases. One issue concerned whether gastroparesis could be reliably diagnosed without objective gastric-emptying testing. Another addressed federal preemption and whether GLP-1 drug labels adequately warned about the gastrointestinal injuries alleged by plaintiffs. General causation later became part of the coordinated expert proceedings, addressing whether the medications are capable of causing the categories of injuries alleged in the MDL.
The FDA reported that labeling for GLP-1 receptor agonists was updated between October and November 2024 to include information about pulmonary aspiration during general anesthesia or deep sedation. The revisions affected sections addressing warnings and precautions, adverse reactions, and patient counseling. In November 2024, the FDA also required a postmarketing trial to examine temporary withholding of GLP-1 drugs, fasting duration, retained gastric contents, and delayed gastric emptying in connection with pulmonary aspiration risk. The labeling changes followed reports of pulmonary aspiration in patients taking GLP-1 medications who underwent procedures requiring general anesthesia or deep sedation.
A Rule 702 ruling issued by Judge Marston addressed the medical evidence used to establish a diagnosis of drug-induced gastroparesis. Plaintiffs offered opinions from Dr. Daniel L. Raines, a gastroenterologist, and Dr. Eliot L. Siegel, a radiologist with experience in nuclear medicine and diagnostic imaging. Defendants offered opinions from Dr. Linda A. Nguyen, a gastroenterologist. The court excluded the challenged opinions from Drs. Raines and Siegel and denied plaintiffs' partial motion concerning Dr. Nguyen.
Under the ruling, a plaintiff alleging drug-induced gastroparesis must have undergone a properly performed gastric-emptying study at the time of diagnosis that confirmed delayed gastric emptying. The court identified gastric-emptying scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test as accepted methods discussed in the record. Judge Marston also recognized that some plaintiffs would be unable to establish gastroparesis because their diagnoses were not supported by the required testing.
The court separately ruled that day on the defendants' motion to dismiss the master complaint. The motion was granted in part and denied in part across the claims presented in the consolidated pleading. Among other rulings, state-law design-defect claims were held preempted to the extent they would require manufacturers to change a GLP-1 drug's formula or dosage without prior FDA approval. Other pleaded theories remained, were narrowed, or could be amended under the court's decision.
The JPML created MDL No. 3163 for federal lawsuits alleging that certain GLP-1 drugs caused NAION. The litigation consisted of 21 actions pending in three districts, and the Panel had also been notified of nine related actions. The centralized cases at that stage involved Ozempic, Wegovy, Saxenda, and Trulicity. Plaintiffs asserted failure-to-warn, design-defect, and breach-of-warranty claims. The JPML identified common factual questions concerning product development, manufacture, testing, regulatory history, promotion, labeling, and the alleged capacity of the drugs to cause NAION. The Panel created a separate MDL rather than transferring the NAION cases into the existing gastrointestinal proceeding.
Judge Marston entered an order setting a Science Day for June 2, 2026. The order called for objective presentations covering diseases treated with GLP-1 medications, the drugs and their labeling and regulatory history, eye anatomy, NAION, and medical literature concerning GLP-1 drugs and the alleged injury. Presentations were limited to publicly available information and excluded discussion of individual plaintiffs and defendants' sales and marketing practices. Attorneys and experts were permitted to make the presentations.
Judge Marston granted the defendants' request for early discovery and motion practice on general causation and federal preemption/warning adequacy. The order described general causation as the question of whether the products are capable of causing the alleged injury, as distinct from whether a drug caused a particular person's condition. At that point, the court described the MDL as involving Ozempic, Wegovy, Rybelsus, Saxenda, Trulicity, Mounjaro, and Zepbound. The parties were directed to meet and confer on a proposed scheduling order for discovery and motion deadlines on the cross-cutting issues. They were also directed to develop a proposed schedule for plaintiff fact sheets and medical records documenting product use and diagnosis.
Judge Marston convened a Rule 702 evidentiary hearing beginning September 14, 2026, with proceedings scheduled through September 18. The hearing concerns Cross-Cutting Issues Nos. 2 and 3 in MDL 3094. Those proceedings address expert evidence associated with warning adequacy, federal preemption, and general causation for gastrointestinal injuries alleged in the litigation. Expert reports, depositions, briefing, and motions challenging proposed expert opinions preceded the hearing.
Dr. Daniel L. Raines was identified as a plaintiffs' expert in the first cross-cutting proceedings. He offered opinions concerning the diagnosis of drug-induced gastroparesis, including the use of differential diagnosis without one of the recognized gastric-emptying studies.
Dr. Linda A. Nguyen was identified as a defendants' expert in the same proceedings. She addressed the diagnostic criteria for gastroparesis and the objective gastric-emptying testing she considered necessary to establish the diagnosis.
Dr. Eliot L. Siegel was identified as a plaintiffs' expert. The court described him as a radiologist with a certification of special competence in nuclear medicine and more than 37 years of experience in diagnostic imaging. His report addressed gastric-emptying scintigraphy and other imaging studies, along with whether those tests were necessary to diagnose drug-induced gastroparesis.
Pharmacology expert witnesses may evaluate how GLP-1 medications act in the body, including their mechanisms of action, dose-response effects, gastric motility, adverse-event data, and findings from clinical studies. In litigation involving alleged drug-related injuries, they may also assess whether the pharmacologic evidence supports a proposed connection between a medication and the claimed condition.
Ophthalmology expert witnesses may address optic-nerve anatomy, NAION diagnosis, visual symptoms, vascular risk factors, and other eye-related medical issues raised in GLP-1 litigation. They may also evaluate clinical findings and medical literature concerning whether a claimed vision injury is consistent with NAION.
MDL 3094 concerns gastrointestinal injuries, while MDL 3163 concerns NAION. Both proceedings are before Judge Marston in the Eastern District of Pennsylvania, but they have separate docket numbers, case-management orders, discovery schedules, and expert proceedings. When the JPML created MDL 3163 in December 2025, it chose separate centralization rather than adding the NAION cases to MDL 3094.
General causation asks whether a product is capable of causing a particular type of injury. Specific causation addresses whether the product caused an individual plaintiff's injury. The court has prioritized general causation for early proceedings in both GLP-1 MDLs, while individual causation and other plaintiff-specific issues remain for later stages.
The August 2025 Rule 702 ruling established an objective diagnostic requirement for plaintiffs alleging drug-induced gastroparesis in MDL 3094. A properly performed gastric-emptying study must have been completed at the time of diagnosis and must have confirmed delayed gastric emptying. The accepted methods discussed in the opinion include scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test.
The warning disputes involve FDA-approved labeling and whether federal law permits additional warnings sought under state law. MDL 3094 placed preemption and warning adequacy among its cross-cutting issues. The July 2026 NAION order authorized early discovery and motion practice on the same subjects in MDL 3163. FDA labeling history also forms part of the regulatory record surrounding the drugs.
Federal Rule of Evidence 702 governs the admissibility of expert opinion evidence in federal court. Judge Marston applied Rule 702 to the gastroparesis diagnostic dispute in August 2025 and is using the same evidentiary framework for the September 2026 hearing concerning Cross-Cutting Issues Nos. 2 and 3. The court considers expert qualifications, the reliability of the methods used, and whether the proposed opinions fit the issues before the court.
The gastrointestinal MDL has moved through centralized pleadings, coordinated discovery, a Rule 702 ruling on gastroparesis diagnosis, partial dismissal of claims in the master complaint, and further expert proceedings on general causation and warning issues. In the separate NAION litigation, the court scheduled a Science Day and later authorized early discovery and motion practice on general causation, federal preemption, and warning adequacy. Judge Marston convened the MDL 3094 Rule 702 hearing in September 2026, while the parties in MDL 3163 were directed to propose schedules for discovery and motions on its cross-cutting issues. Both proceedings remain pending in the Eastern District of Pennsylvania.
When was MDL 3094 created and where is it pending?
The JPML created MDL 3094 on February 2, 2024. It centralized 18 actions pending in 11 districts and identified another 37 related actions at the time. The proceeding is pending in the U.S. District Court for the Eastern District of Pennsylvania before Judge Karen S. Marston.
Which drugs are addressed in the MDL 3094 master complaint?
The August 2025 court opinion identifies eight medications at issue in the master complaint: Ozempic, Wegovy, Rybelsus, Victoza, Saxenda, Trulicity, Mounjaro, and Zepbound. The court noted that the JPML had not separately identified Victoza and Zepbound by name when transferring cases, but the parties agreed that they were properly included because Victoza and Saxenda contain liraglutide, while Mounjaro and Zepbound contain tirzepatide.
What did the 2025 gastroparesis ruling require?
Judge Marston ruled that a plaintiff alleging drug-induced gastroparesis must have a properly performed gastric-emptying study from the time of diagnosis confirming delayed gastric emptying. The recognized tests discussed by the court were gastric-emptying scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test. The ruling followed challenges to opinions offered by Drs. Raines, Siegel, and Nguyen.
Why are the NAION lawsuits in a separate MDL?
When the JPML considered the NAION cases in 2025, Eli Lilly requested either a new MDL in the Eastern District of Pennsylvania or transfer of the cases into MDL 3094. The Panel chose separate centralization and created MDL 3163. The transfer order identified common factual questions involving product development, manufacture, testing, regulatory history, promotion, labeling, and the alleged capacity of GLP-1 drugs to cause NAION.
What is happening in MDL 3094 in September 2026?
Judge Marston convened a Rule 702 evidentiary hearing beginning September 14, 2026, with proceedings scheduled through September 18. The hearing concerns Cross-Cutting Issues Nos. 2 and 3, including warning adequacy, federal preemption, and general-causation expert evidence. It follows written expert reports, depositions, briefing, and motions concerning the admissibility of proposed opinions.
Dr. Daniel L. Raines was identified as a plaintiffs' expert in the first cross-cutting proceedings. He offered opinions concerning the diagnosis of drug-induced gastroparesis, including the use of differential diagnosis without one of the recognized gastric-emptying studies.
Dr. Linda A. Nguyen was identified as a defendants' expert in the same proceedings. She addressed the diagnostic criteria for gastroparesis and the objective gastric-emptying testing she considered necessary to establish the diagnosis.
Dr. Eliot L. Siegel was identified as a plaintiffs' expert. The court described him as a radiologist with a certification of special competence in nuclear medicine and more than 37 years of experience in diagnostic imaging. His report addressed gastric-emptying scintigraphy and other imaging studies, along with whether those tests were necessary to diagnose drug-induced gastroparesis.
Pharmacology expert witnesses may evaluate how GLP-1 medications act in the body, including their mechanisms of action, dose-response effects, gastric motility, adverse-event data, and findings from clinical studies. In litigation involving alleged drug-related injuries, they may also assess whether the pharmacologic evidence supports a proposed connection between a medication and the claimed condition.
Ophthalmology expert witnesses may address optic-nerve anatomy, NAION diagnosis, visual symptoms, vascular risk factors, and other eye-related medical issues raised in GLP-1 litigation. They may also evaluate clinical findings and medical literature concerning whether a claimed vision injury is consistent with NAION.
MDL 3094 concerns gastrointestinal injuries, while MDL 3163 concerns NAION. Both proceedings are before Judge Marston in the Eastern District of Pennsylvania, but they have separate docket numbers, case-management orders, discovery schedules, and expert proceedings. When the JPML created MDL 3163 in December 2025, it chose separate centralization rather than adding the NAION cases to MDL 3094.
General causation asks whether a product is capable of causing a particular type of injury. Specific causation addresses whether the product caused an individual plaintiff's injury. The court has prioritized general causation for early proceedings in both GLP-1 MDLs, while individual causation and other plaintiff-specific issues remain for later stages.
The August 2025 Rule 702 ruling established an objective diagnostic requirement for plaintiffs alleging drug-induced gastroparesis in MDL 3094. A properly performed gastric-emptying study must have been completed at the time of diagnosis and must have confirmed delayed gastric emptying. The accepted methods discussed in the opinion include scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test.
The warning disputes involve FDA-approved labeling and whether federal law permits additional warnings sought under state law. MDL 3094 placed preemption and warning adequacy among its cross-cutting issues. The July 2026 NAION order authorized early discovery and motion practice on the same subjects in MDL 3163. FDA labeling history also forms part of the regulatory record surrounding the drugs.
Federal Rule of Evidence 702 governs the admissibility of expert opinion evidence in federal court. Judge Marston applied Rule 702 to the gastroparesis diagnostic dispute in August 2025 and is using the same evidentiary framework for the September 2026 hearing concerning Cross-Cutting Issues Nos. 2 and 3. The court considers expert qualifications, the reliability of the methods used, and whether the proposed opinions fit the issues before the court.
The gastrointestinal MDL has moved through centralized pleadings, coordinated discovery, a Rule 702 ruling on gastroparesis diagnosis, partial dismissal of claims in the master complaint, and further expert proceedings on general causation and warning issues. In the separate NAION litigation, the court scheduled a Science Day and later authorized early discovery and motion practice on general causation, federal preemption, and warning adequacy. Judge Marston convened the MDL 3094 Rule 702 hearing in September 2026, while the parties in MDL 3163 were directed to propose schedules for discovery and motions on its cross-cutting issues. Both proceedings remain pending in the Eastern District of Pennsylvania.
When was MDL 3094 created and where is it pending?
The JPML created MDL 3094 on February 2, 2024. It centralized 18 actions pending in 11 districts and identified another 37 related actions at the time. The proceeding is pending in the U.S. District Court for the Eastern District of Pennsylvania before Judge Karen S. Marston.
Which drugs are addressed in the MDL 3094 master complaint?
The August 2025 court opinion identifies eight medications at issue in the master complaint: Ozempic, Wegovy, Rybelsus, Victoza, Saxenda, Trulicity, Mounjaro, and Zepbound. The court noted that the JPML had not separately identified Victoza and Zepbound by name when transferring cases, but the parties agreed that they were properly included because Victoza and Saxenda contain liraglutide, while Mounjaro and Zepbound contain tirzepatide.
What did the 2025 gastroparesis ruling require?
Judge Marston ruled that a plaintiff alleging drug-induced gastroparesis must have a properly performed gastric-emptying study from the time of diagnosis confirming delayed gastric emptying. The recognized tests discussed by the court were gastric-emptying scintigraphy, a gastric-emptying breath test, and a wireless motility capsule test. The ruling followed challenges to opinions offered by Drs. Raines, Siegel, and Nguyen.
Why are the NAION lawsuits in a separate MDL?
When the JPML considered the NAION cases in 2025, Eli Lilly requested either a new MDL in the Eastern District of Pennsylvania or transfer of the cases into MDL 3094. The Panel chose separate centralization and created MDL 3163. The transfer order identified common factual questions involving product development, manufacture, testing, regulatory history, promotion, labeling, and the alleged capacity of GLP-1 drugs to cause NAION.
What is happening in MDL 3094 in September 2026?
Judge Marston convened a Rule 702 evidentiary hearing beginning September 14, 2026, with proceedings scheduled through September 18. The hearing concerns Cross-Cutting Issues Nos. 2 and 3, including warning adequacy, federal preemption, and general-causation expert evidence. It follows written expert reports, depositions, briefing, and motions concerning the admissibility of proposed opinions.
Drug Labels
Drug Regulation
Drug Research
Pharmacodynamics
Pharmacokinetics
Medical Research
Medical Imaging
Safety Warnings
Vision Loss
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Pharmaceutical
Securities, +4
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