According to a new study, people taking a very popular diabetes and weight loss drug may be at an increased risk of a rare vision disorder that could lead to blindness. Researchers at Mass Eye and Ear, a teaching hospital affiliated with Harvard University in Boston, found that patients taking semaglutide (marketed as Ozenpic and Wegovy) were more likely to develop non-arteritic anterior ischemic optic neuropathy (NAION).
The stock of the company behind Ozenpic, Novo Nordisk, dropped significantly after the report was released.
The study found that diabetes patients taking semaglutide were about four times more likely to be diagnosed with NAION compared to those not taking the drug. Overweight or obese patients had an even higher risk, with over seven times the likelihood of developing the condition compared to other patients.
NAION is a rare condition, affecting only 2-10 people per 100,000. It involves a potential decrease in blood flow to the optic nerve, which can result in permanent vision loss.
The lead author of the study and Director of Mass Eye and Ear, Joseph Rizzo, stated, “The use of these drugs has exploded in industrialized countries and offers very significant benefits in many ways, but future discussions between patients and doctors should consider NAION as a potential risk.”
Novo Nordisk told the National Post that despite taking negative reports “very seriously,” it remains confident in the safety of Ozenpic.
The company stated, “Semaglutide has been studied in large real-world evidence studies and robust clinical development programs, with over 22 million patient years of exposure since launch.” “The totality of the data provides assurance of the safety of semaglutide.”
The company did not immediately respond to Decrypt’s request for comment.
Novo Nordisk’s stock fell nearly 5% to $136 on Wednesday, before recovering slightly to close at $138.60. This news also seemed to affect pharmaceutical company Eli Lilly (LLY), which produces similar diabetes and weight-loss drugs Mounjaro and Zepbound, as its stock fell nearly 3% to close at $898.10.
Ozenpic was first approved by the U.S. Food and Drug Administration for the treatment of type 2 diabetes in December 2017, and its global sales quickly reached $1 billion within the first two years of being on the market.
The drug works by mimicking the action of the GLP-1 hormone, which helps regulate appetite and blood sugar levels. This mechanism makes patients feel fuller and less hungry, leading to reduced calorie intake and weight loss. In clinical studies, obese individuals taking Ozenpic in addition to lifestyle changes lost more weight than those not taking the drug.
Ozenpic is primarily used to improve blood sugar levels in adults with type 2 diabetes and reduce the risk of major cardiovascular events in diagnosed heart disease patients, but due to its effectiveness, many healthcare providers have been prescribing it for weight loss.
The researchers noted that the risk of developing NAION was highest within the first year of starting treatment with semaglutide. However, they emphasized that this study cannot conclusively prove that Ozenpic or Wegovy directly cause NAION, and further research is needed to establish causality.
In response to the study, some experts advised caution.
Neuro-ophthalmologist Susan Moran in Birmingham, UK, told Bloomberg, “I think this is not a strong enough signal to stop the medication for patients.”
The release of the study’s results comes at a time when Ozenpic and similar drugs have been hailed as game-changers in the treatment of diabetes and obesity. Their popularity has surged to the point where the market has struggled to keep up with demand, creating a lucrative market for pharmaceutical companies.
In a previous controversy, a study in March 2024 concluded that Ozenpic could be profitable at a cost of less than $5 per month, a stark contrast to its current U.S. price of $915. Despite this, demand for the drug has not decreased, and the price has not fallen. Novo Nordisk’s stock fell by more than 12% after the cost study was released, but quickly rebounded.
Another popular drug, Viagra, is also associated with vision problems and remains widely used.
Edited by Ryan Ozawa.
