GLP-1 Rule 702 Hearing: What Sept. 10-18 Decides

GLP-1 Litigation's Biggest Test Yet: The September 10-18 Rule 702 Hearing

The biggest test yet for the GLP-1 gastrointestinal injury litigation arrives this month. From September 10 through 18, 2026, Judge Karen S. Marston will hold a Rule 702 hearing in MDL 3094, the federal multidistrict litigation consolidating gastrointestinal injury claims against the makers of Ozempic, Wegovy, Mounjaro, and related GLP-1 medications, to decide whether plaintiffs' general-causation experts can testify at all.

Under Rule 702 and Daubert v. Merrell Dow Pharmaceuticals, a judge screens expert science before a jury ever hears it, admitting only opinions built on reliable methods that were reliably applied. The September hearing takes up defense motions against eight of plaintiffs' experts, plus summary judgment motions on several injury categories. No jury will be present, and no verdict will issue. What the court decides determines whether the litigation's central scientific claim survives to reach one.

Two MDLs, One Judge, Two Different Science Questions

What's Actually Being Challenged

Novo Nordisk's briefing frames the hearing around a small number of core causation opinions: whether GLP-1 receptor agonists generally, and each defendant's specific products, are capable of causing (1) ileus or bowel obstruction and (2) persistent gastroparesis, as distinct from the transient, labeled effect of delayed gastric emptying. Novo alone filed five motions to exclude, including one aimed at Dr. David Metz, the retired gastroenterologist who is plaintiffs' primary causation expert on persistent gastroparesis, and one covering Drs. Binu John and Nilesh Lodhia on ileus and intestinal obstruction.

Novo's brief argues that Dr. Metz conceded "there simply is no reported literature of any kind" investigating prolonged or permanent gastroparesis injury with these medications. The company is not challenging testimony that GLP-1 drugs cause transient drug-induced delayed gastric emptying, which it calls a well-known, labeled effect of the medicines' mechanism of action. The dispute is over persistence: whether the drugs can leave a stomach impaired months after a patient stops taking them.

The court has already shown it takes this gatekeeping role seriously. In an August 15, 2025 order, Judge Marston ruled that any plaintiff claiming gastroparesis, under whatever label (drug-induced gastroparesis, delayed gastric emptying, or another term), must show the diagnosis rests on a properly performed objective gastric emptying study: scintigraphy, a validated breath test, or a wireless motility capsule study. Diagnoses based on self-reported symptoms or clinical suspicion alone do not clear that bar. The September hearing applies the same scrutiny to the underlying question of whether the drugs can cause the injury at all.

Why the Records Matter More Than Ever

If the court's ruling narrows or excludes the causation experts, cases that lack the specific documentation those experts rely on become substantially harder to salvage. If the experts survive, the litigation moves toward case-specific work, and objective testing becomes the dividing line between viable and non-viable individual claims.

A typical GLP-1 claimant's file spans prescribing physicians (primary care, endocrinology, or bariatric specialists), retail or mail-order pharmacies, the gastroenterologist who performed the motility study, and emergency departments or hospitals for acute episodes. For NAION claims, add ophthalmology and neuro-ophthalmology records documenting the vision loss and its differential diagnosis. LlamaLab retrieves records across all of these settings in 4 days on average, with 30 to 40% of electronic requests returned same-day, and uses insurance data to surface treatment locations claimants don't always remember.

What to Watch After September 18

If the litigation does move to bellwethers, the recent NEC infant formula docket shows how fast a first trial can reshape settlement posture.

The Bottom Line

This is not a trial and will not produce a verdict, but it will determine whether the GLP-1 litigation's central scientific theory survives in a form a jury will ever hear. Firms with cases lacking objective gastric emptying documentation should treat this hearing as a warning, not a footnote: whatever the court decides about the experts, individual claims still need the diagnostic testing the court has already said the science requires.

Sources: U.S. District Court, E.D. Pa.: MDL 3094 docket, MDL 3094 Case Management Order No. 32 (Apr. 30, 2026), MDL Update: August 2026 MDL Statistics, Novo Nordisk Rule 702 and Summary Judgment Brief (May 2026), Miller & Zois: Ozempic Lawsuit Litigation News (Aug. 2026), and the Order on Cross-Cutting Issue 1 / Dkt. 468 (Aug. 15, 2025). Case counts current as of the JPML's August 2026 report (Aug. 1, 2026 pending-actions date).