Rule 702 general causation hearing opens in MDL 3094

A federal judge in Philadelphia opened a multi-day hearing on September 14, 2026, that will decide whether the scientific backbone of the GLP-1 stomach-injury lawsuits ever reaches a jury. U.S. District Judge Karen S. Marston is holding a Rule 702 evidentiary hearing — often called a "Daubert" hearing — on "Cross Cutting Issues 2 and 3" in MDL 3094, the consolidated litigation over gastrointestinal injuries allegedly caused by GLP-1 receptor agonists ^[1]. The court's own page says the hearing runs from September 14 through September 18, 2026 ^[1]. No ruling had issued as of the hearing's opening day.

What is actually being decided

In federal court, a judge acts as a gatekeeper for expert testimony. Before a jury can hear a scientist say a drug is capable of causing a particular injury, the judge must find that the opinion rests on reliable methods, reliably applied ^[2]. That question — whether GLP-1 drugs can cause the alleged injuries at all — is called general causation.

According to a law firm tracking the docket, the defense has moved to exclude eight of the plaintiffs' experts and has also filed for summary judgment on multiple injury categories ^[2]. If the general-causation experts are excluded, affected claims cannot proceed; if the opinions survive, the litigation moves toward case-specific work with its central scientific question intact ^[2].

MDL 3094 covers claims that GLP-1 drugs caused gastroparesis (sometimes called stomach paralysis), ileus, intestinal obstruction or pseudo-obstruction, ischemic bowel, pancreatitis, gallbladder injury, aspiration, and in some cases death, and that manufacturers failed to warn patients and doctors adequately ^[3]. The court's page names Ozempic, Wegovy and Rybelsus (semaglutide, made by Novo Nordisk) and Trulicity and Mounjaro (Eli Lilly) ^[1]; other court materials also identify Victoza and Saxenda (liraglutide) and Zepbound (tirzepatide) as within the litigation's scope ^[3]. Novo Nordisk and Eli Lilly deny the allegations ^[1].

How big the docket is

The Judicial Panel on Multidistrict Litigation counted 3,848 pending actions in MDL 3094 as of July 1, 2026, up from 37 when the cases were centralized on February 2, 2024 ^[3]. Filings had been running roughly 85 to 275 new federal cases a month through spring and early summer 2026 ^[3]. One law firm page put the number of affected cases at 3,928 as of August 2026 ^[2].

Sources disagree on the hearing dates. The court's own notice says September 14–18 ^[1], and one law firm page says the same ^[2]; an earlier litigation tracker reported the court had reserved September 10 through 18, 2026 ^[3].

Why it matters for patients

Nothing about this hearing changes how these medicines are prescribed, labeled or sold. It is a courtroom fight about evidence, not a regulatory action.

For people who have filed or are considering claims, the practical stakes are large. There is no settlement in MDL 3094, no certified class and no claim form; no court or jury has found that these medications caused anyone's injury ^[2][3]. Anyone describing a payout available today is not describing this litigation accurately ^[3]. Participation means filing an individual lawsuit, which is why the docket keeps growing even though there is nothing to "claim" ^[3].

The court has already narrowed things once. In an August 15, 2025 ruling on the motion to dismiss, Judge Marston let warranty and negligent-undertaking claims proceed, narrowed the fraud theories, required amendment of consumer-protection and certain product-liability claims, and dismissed the medical-monitoring request with leave to amend ^[3]. A law firm summary also says the court excluded two plaintiff diagnostic experts and held that gastroparesis claims require an objective gastric emptying study ^[2].

Vision-loss claims are not part of this MDL. In December 2025 the JPML created MDL 3163 for NAION and other vision-loss claims tied to GLP-1 drugs — 110 pending actions as of June 1, 2026 — also before Judge Marston ^[3].

What happens next

The hearing is scheduled to end September 18, 2026 ^[1]. There is no deadline for a decision; rulings after multi-day Rule 702 hearings commonly take weeks to months ^[2]. No bellwether trial date has been set, and the court chose to resolve preemption, warnings and general causation before selecting test cases — putting any first trial in 2027 at the earliest if the litigation survives those rulings ^[3].