FDA issues new eye safety warning for GLP-1 medications

The US Food and Drug Administration (FDA) has ordered manufacturers of GLP-1 receptor agonists to update product labels with a warning about non-arteritic anterior ischaemic optic neuropathy (NAION), a rare eye condition that can cause sudden and permanent vision loss.

The warning applies to GLP-1 medicines used to treat type 2 diabetes and obesity, including medications from rom Eli Lilly and Novo Nordisk.

What is NAION?

NAION, sometimes referred to as an 'eye stroke', occurs when blood flow to the optic nerve is reduced.

The FDA states that symptoms can include sudden, painless decreased vision in one eye, which may result in permanent sight loss.

Following a review of clinical trials, animal studies and post-marketing data, the FDA identified reports of NAION across all currently marketed GLP-1 agonists, estimating an incidence of approximately six cases per 100,000 users.

Last year, the EMA carried out a review of Novo Nordisk's GLP-1 agonist semaglutide, used in its Ozempic and Wegovy products, which concluded that NAION is a "very rare side effect" of the drug that may affect "up to (one) in 10,000 people" taking the drug for at least a year.

How have pharmaceutical companies responded to the FDA GLP-1 warning?

Both Novo Nordisk and Eli Lilly have responded to the updated warning, with Novo stating that whilst patient safety is its top priority, it does not believe there is a clear cause-and-effect relationship between semaglutide and NAION and it remains confident in the benefit-risk profile of its GLP-1 medicines.

Lilly confirmed it would evaluate the FDA's update and continue monitoring safety data.

Both companies are facing lawsuits from patients who are claiming they suffered vision loss as a result of exposure to their GLP-1 medicines.