Rule 702 expert hearing tests whether GLP-1 drugs can cause gastroparesis

The central legal fight over whether drugs like Ozempic, Wegovy and Mounjaro can cause gastroparesis — sometimes called stomach paralysis — has reached its decisive stage. In MDL 3094, the consolidated federal litigation before Judge Karen S. Marston in the Eastern District of Pennsylvania, expert depositions wrapped up in April 2026, motions to exclude expert testimony were due April 28, 2026, and summary judgment briefing has been running through July 2026 ^[1].

Those motions are filed under Federal Rule of Evidence 702, the standard courts use to decide whether an expert's scientific opinion is reliable enough for a jury to hear. In drug cases, the first hurdle is "general causation": can the medicine cause the injury at all, in anyone? If the judge excludes the plaintiffs' general causation experts, most claims in the MDL cannot proceed. If the experts survive, the litigation moves toward bellwether trials — test cases whose outcomes often shape settlement talks ^[1].

Where the case stands

As of September 2026, 4,022 cases were pending in MDL 3094, out of 4,056 total filed, with hundreds of new filings each month ^[1][2]. By one count in the same tracker, filings have grown roughly 200% since January 2025, when the docket stood at 1,331 cases; the source gives both 195% and 202% growth figures in different places, so the exact percentage is uncertain ^[1]. Roughly 75% of complaints allege gastroparesis or stomach paralysis, 18% allege ileus, and 8% allege gallbladder injuries ^[1].

The defendants are Novo Nordisk, maker of the semaglutide products Ozempic, Wegovy and Rybelsus, and Eli Lilly, maker of tirzepatide (Mounjaro, Zepbound) and dulaglutide (Trulicity). Liraglutide products Victoza and Saxenda are also named ^[1]. Plaintiffs allege the companies failed to warn that delayed stomach emptying — a known mechanism of these drugs — can progress to severe, persistent gastroparesis, bowel obstruction and related complications ^[1][2].

Much of the scientific argument traces back to an October 2023 JAMA research letter by Sodhi and colleagues, which reported higher risks among people using GLP-1 drugs for weight loss: 9.09 times higher for pancreatitis, 4.22 times higher for bowel obstruction and 3.67 times higher for gastroparesis ^[1]. Judge Marston has already narrowed who can sue: in August 2025, after more than 3,700 pages of briefing and evidentiary hearings, she issued a 78-page ruling on gastroparesis diagnosis requirements, and she continues to require objective diagnostic testing — typically a gastric emptying study showing more than 10% retention at four hours ^[1].

The sources disagree on labeling dates. One says the FDA added the language "OZEMPIC is not recommended in patients with severe gastroparesis" in October 2025 ^[1]. The other dates that same wording to January 2025 and notes it does not say the drug causes the condition ^[2]. Both agree an ileus warning was added in September 2023 ^[1][2].

Why it matters for patients

A Rule 702 ruling is a legal decision about evidence, not a medical verdict. Excluding experts would not mean the drugs are proven safe, and admitting them would not mean the drugs are proven to cause gastroparesis. Allegations in the MDL remain unproven; no settlements had been announced as of September 2026 ^[1][2].

Still, the hearing has practical spillover. Litigation discovery and public rulings often surface internal company documents and shape how warnings are written. The current labels describe delayed gastric emptying as part of how these drugs work and warn about ileus, intestinal obstruction, acute pancreatitis and aspiration risk during anesthesia, and carry a boxed warning about thyroid C-cell tumors seen in rodents, whose human relevance has not been determined ^[1].

For people who believe they were harmed, the court's documentation requirements matter: claims are being evaluated against objective testing, and statutes of limitations generally run two to three years from discovery of the injury, varying by state ^[1]. Note that both sources are law-firm-affiliated litigation trackers carrying attorney advertising, including a "legal analysts" estimate that liability across the two GLP-1 MDLs could exceed $2 billion ^[1].

What happens next

Bellwether trial selection was expected around mid-2026, with the first trials possible in late 2026 and mass settlements considered unlikely before late 2027 ^[1]. A separate MDL, 3163, created in December 2025 and also before Judge Marston, handles NAION vision-loss claims and stood at about 200 cases in September 2026 ^[1][2]. A specific date for a ruling on the Rule 702 motions is not stated in the available sources.