Hundreds of NAION "Vision Loss" Lawsuits Pile Onto Novo and Lilly as a Federal MDL Takes Shape
A safety-liability overhang is crystallizing around the GLP-1 class: hundreds of personal-injury lawsuits alleging that Ozempic, Wegovy, Mounjaro, Zepbound, and Trulicity caused NAION (non-arteritic anterior ischemic optic neuropathy) — sudden, often permanent vision loss — are now consolidated in federal litigation, MDL-3163 (In re GLP-1 RAs Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) Products Liability Litigation, consolidated by a December 2025 order), alongside state-court dockets (MassLive; CourtListener docket).
Scale and allegations. Per Al Jazeera's summary of the WSJ report: "A personal-injury firm in the US called Weitz & Luxembourg has filed more than 90 lawsuits against Novo Nordisk in a New Jersey state court since 2025." Plaintiffs claim the manufacturers "knew their products could cause NAION but failed to warn users by not putting the risk on GLP-1 labels." A July Pennsylvania state-court suit (quoted by USA Today) alleges: "Defendants' efforts to conceal (or minimize) the risks associated with taking their drugs, including the risk of developing NAION were intended to create the impression that these were 'magic pills' to help a person lose weight."
The state of the science is genuinely mixed — which is what makes the litigation hard to price:
- Supporting association: a 2024 JAMA Ophthalmology study of ~17,000 patients (Mass Eye and Ear) and a 2025 study in Diabetes, Obesity and Metabolism; one theory holds GLP-1 receptors sit on the optic nerve itself.
- Against: Novo's own randomized trial program found no increased NAION risk. Dr. Tina Vilsbøll, Novo's senior medical officer and the study's lead author, "said she sees 'no causality' and there are no 'indications that we should really be worried about NAION'" (Al Jazeera).
- Regulators split: the EMA concluded NAION is "a very rare side effect" of semaglutide (~1 in 10,000 users with diabetes), and Novo updated its EU labels in June 2026 to say so — but the FDA requires no vision warning on US labels, though it is investigating (USA Today; The Hill).
Company posture: Novo calls the US suits "without merit" and is vigorously defending; Lilly declined comment on litigation while reviewing the data, and both point to diabetic patients' inherently elevated blindness risk.
Meaning: the disclosure gap between EU labels (1-in-10,000 NAION warning) and US labels (nothing) is the plaintiffs' central exhibit, and the asymmetry gives defense lawyers an obvious target. For the investment story this is a tail risk, not a thesis driver — but an MDL with class-wide reach against both duopoly members is worth tracking as it matures, especially alongside the separate Novo–Lilly advertising war (see Novo's Bid to Block Lilly's GLP-1 Ads: Preliminary Injunction Motion Filed, No Ruling Yet).