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FDA investigates possible link between GLP-1 drugs and rare eye condition amid New Jersey lawsuits
The FDA is investigating whether GLP-1 drugs cause sudden vision loss, and the New Jersey filings number in the dozens. The market those drugs sell into is projected at $92 billion this year.
The Investor · Invest desk
What happened
- Weitz & Luxenberg has filed more than 90 suits in New Jersey state court since 2025 for patients who say they developed NAION after using Ozempic or Wegovy.
- The Food and Drug Administration is investigating a potential link to NAION, in which reduced blood flow to the optic nerve can cause sudden vision impairment or loss.
- Novo's chief medical officer, Tina Vilsboll, told the Wall Street Journal there was no signal that NAION should be a genuine concern and that no causal relationship was apparent.
- Amgen is in Phase 3 with MariTide, including trials that switch patients from weekly semaglutide or tirzepatide to an injection every eight weeks or once a quarter.
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Why it matters
- contradiction Novo's defence rests on randomized trial data while the claims draw on observational studies that the record itself describes as inconsistent, so the FDA is adjudicating between two evidence bases before any jury weighs either.
- constraint Without a plaintiff count for the Philadelphia cases or any damages figure, an investor pricing this has only the filed-case count to track, and that count currently sits in the dozens.
- decision Both makers are answering the safety question through lawyers and the regulator while funding launches, so capital is not being redirected into reformulating around the eye risk.
- exposure Amgen's switch arms aim at the weekly base Novo and Lilly already hold, meaning each converted patient is revenue moved between companies and not new demand.
IQVIA projects the world obesity drug market at $92 billion this year, up from $66 billion last year [15]. Set the New Jersey filings against that and you get roughly one suit for every billion dollars of this year's market [1].
The claims in New Jersey name Ozempic and Wegovy, both Novo's [2]. Lilly turns up in the federal cases in Philadelphia, where patients are suing both companies [3], and in the wider set of claims that also name Zepbound [1]. The report does not say how many plaintiffs the Philadelphia cases involve, or what damages anyone is seeking.
Mounjaro sold $9.943 billion in the second quarter against $18.605 billion for the half [11][12], so the first quarter was $8.662 billion and the second ran 14.8% above it [2]. Annualise the $27.693 billion of combined tirzepatide sales and you reach $55.386 billion, about 60% of IQVIA's figure for the entire obesity market this year [4]. Mounjaro is sold for diabetes, so the two totals count different patients [12].
Some studies have found higher NAION risk among GLP-1 users. Findings across studies have been inconsistent, and causation is not established [5]. Novo says an analysis of randomized controlled trial data for its GLP-1 treatments found no increase in NAION risk [7]. Lilly has argued in court filings that research to date cannot establish that GLP-1 drugs cause NAION and that its medicines are safe and effective [10].
A warning on the label would reach every prescription written after it, while the suits reach only the patients who filed. In my view the FDA's investigation [6] is where the near-term revenue risk sits, and the counter-case is a volume argument: ninety-odd plaintiffs round away against half-year tirzepatide sales [2][14], several thousand would not. And the observational studies are the ones plaintiff firms can keep filing on [5].
The spending, meanwhile, is going into how often a patient has to dose. Novo and Lilly each launched an oral obesity drug in the US this year [18]. Lilly said this month that Foundayo had taken more than 30% of US patients newly starting an oral obesity drug [19], and Novo expects orals to account for more than a third of GLP-1-based obesity treatment use by 2030 [20]. A third of IQVIA's post-2027 range would be $35 billion to $67 billion, though Novo's forecast is a share of use and not of revenue [6].
That range is $105 billion to $200 billion [16]. Its top is about 1.9 times its bottom, a spread of $95 billion [5].
What to watch
- Whether the FDA's investigation ends with NAION warning language on the GLP-1 labels.
- Whether Novo or Lilly books a litigation reserve or discloses case counts in quarterly filings.
- Results from the MariTide Phase 3 arms switching weekly semaglutide and tirzepatide patients to eight-week and quarterly dosing.