Link Between NAION and Ozempic, Wegovy Will Be Focus of Early Discovery in GLP-1 Vision Loss Lawsuits

Court has directed lawyers to focus early discovery on certain “cross cutting” issues likely to impact all of the Ozempic and Wegovy NAION lawsuits, including evidence establishing GLP-1 drugs can cause the vision loss claimed.

The U.S. District Judge presiding over all federal Wegovy and Ozempic NAION lawsuits has directed the parties to focus early discovery on whether plaintiffs can establish that side effects of the GLP-1 medications can cause vision loss, as well as whether federal law preempts their failure-to-warn claims.

Ozempic and Wegovy belong to a class of medications known as glucagon-like peptide-1 (GLP-1) receptor agonists, which have become widely popular in recent years. Originally designated for the treatment of Type 2 diabetes, the drugs have become blockbuster medications as they have been increasingly linked to weight loss and other metabolic health benefits.

The class includes diabetes drugs like Ozempic, Mounjaro, Saxenda, Trulicity, Victoza and Rybelsus, as well as the weight loss compounds Wegovy and Zepbound. However, the manufacturers, Novo Nordisk and Eli Lilly, now face more than 130 GLP-1 vision loss lawsuits filed nationwide, with most focused on the drugs Ozempic and Wegovy.

The litigation began following publication of a study in July 2024 linking GLP-1 use to non-arteritic anterior ischemic optic neuropathy (NAION), a condition caused by a lack of sufficient blood flow to the optic nerve. Ozempic and Wegovy were linked to a seven-fold increased risk in the condition when compared to other drugs. However, research has also seen increased risks across the GLP-1 class.

Each complaint alleges that the manufacturers knew, or should have known, of the potential vision loss risks, which can occur suddenly and result in permanent blurred or reduced vision and blindness. The lawsuits claim the drug makers placed profits ahead of patient safety in order to maximize revenue.

GLP-1 Vision Loss Bellwether Trials

Due to common questions of fact and law, all Ozempic and Wegovy vision loss lawsuits are consolidated in the Eastern District of Pennsylvania before U.S. District Judge Karen Marston, who is overseeing the litigation through pretrial proceedings and coordinated discovery.

The judge is expected to schedule a series of early test trials to help the parties determine how juries may respond to evidence and testimony likely to be repeated throughout the litigation. These “bellwether” trials’ outcomes could provide a basis for potential settlement negotiations.

However, the parties must first go through a discovery process in which they collect evidence, records and testimony in support of their arguments. This involves both sides turning over various records, such as clinical trial data, patient use histories, medical reports and taking depositions from expert witnesses.

According to a case management order (PDF) issued by Judge Marston on July 2, lawyers for plaintiffs and defendants have disagreed on how the discovery should be conducted. Plaintiffs wanted to dive right into the main discovery process to promote efficiency and begin preparing a group of test cases for early trials. However, defendants sought a period of early discovery that focused on determining whether general causation can be proved and whether the lawsuits are disqualified because they are preempted by federal law.

Judge Marston agreed with defendants, calling for early discovery on these “cross-cutting issues” to be handled first. She disagreed with plaintiffs’ arguments that the early discovery could slow the litigation down substantially, noting that defendants have suggested fact discovery be completed by October 2026, expert discovery by the end of 2026 and calls for motions to be fully briefed by the first quarter of 2027.

“Most importantly, while the parties proceed on these cross cutting issues, they will also begin exchanging marketing discovery in line with the parties’ agreement and producing Plaintiffs’ fact sheets so that if this case is not resolved on the early cross cutting motions, the parties will be ready to select bellwether cases in short order.”

– U.S. District Judge Karen Marston

The order calls for the parties to meet and confer in preparation to submit a proposed scheduling order by July 13, 2026.

GLP-1 Stomach Paralysis Lawsuits

One of the plaintiffs’ concerns was that the proposed early discovery process could delay the vision loss litigation and cause it to fall out of sync with a separate GLP-1 multidistrict litigation involving gastrointestinal injuries, which is also being overseen by Judge Marston.

That parallel MDL involves thousands of GLP-1 stomach paralysis lawsuits alleging Ozempic, Wegovy and similar GLP-1 medications caused severe gastrointestinal injuries, including gastroparesis, intestinal blockages and other digestive complications. Although many of the same manufacturers are defendants in both proceedings, the vision loss and gastrointestinal cases remain separate MDLs involving different injuries, scientific evidence and legal issues.

Judge Marston is also preparing the stomach paralysis litigation for its own bellwether process, which will involve a separate group of representative cases selected to test the claims and defenses specific to gastrointestinal injuries. The NAION litigation will proceed through an independent bellwether process focused on the evidence surrounding vision loss.

If either MDL is not resolved through settlement or other pretrial proceedings, cases from that litigation may eventually be returned to their original federal courts for individual trials.

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