Novo Nordisk weight-loss drugs linked to rare eye disease, study finds

A box of Ozempic and its contents on a table in Dudley, North Tyneside, Britain, October 31, 2023.

George Frey | Reuters

Novo Nordisk investors appeared unfazed on Thursday by a critical Harvard report linking weight-loss drugs to a rare eye disease.

Semaglutide, found in weight-loss drugs such as Novo Nordisk's Ozempic and Wegovy, may be associated with an increased risk of a rare eye disease, according to a study by Harvard Medical School.

However, analysts said the study results were “not game-changing.” Shares in the Danish pharmaceutical company were little changed on Thursday, falling in early morning trading before rising 0.1% by 11:17 a.m. London time.

The Harvard report found that patients with type 2 diabetes or obesity who are prescribed semaglutide have a higher risk of non-arteritic anterior ischemic optic neuropathy (NAION), a condition that can lead to vision loss in one eye. Patients were more likely to be diagnosed with the eye condition compared with patients who were not prescribed the weight-loss drugs, according to the study.

While the research paper suggests “some correlation” with a rare ocular event, the quality of the evidence is “very low and the margins of error are very wide,” according to Deutsche Bank analyst Emmanuel Papadakis.

The worst-case scenario would likely be a further update to the warning section of drug labels, which “is not a radical change,” Papadakis said.

He added that Deutsche Bank generally views semaglutide drugs as “one of the lowest risk therapeutic classes in the history of the industry from a safety perspective.”

A Novo Nordisk spokesman said optic nerve disease NATION It is not an “adverse drug reaction to marketed formulations of semaglutide,” according to the approved labels. They added that there are “key methodological limitations” to the study, such as the “small number of people” with type 2 diabetes or obesity who were exposed to semaglutide and included in the trial.

“Patient safety is a top priority for Novo Nordisk and we take all reports of adverse events arising from the use of our medicines very seriously,” the spokesperson said.

The popularity of its blockbuster drugs has made Novo Nordisk Europe's most valuable company, valued more than Denmark's entire gross domestic product last year.

Wegovy has also been shown to have health benefits beyond weight loss and blood sugar regulation. In March, the Food and Drug Administration approved its use to reduce the risk of heart disease.

However, these drugs have come under scrutiny after some patients reported experiencing stomach paralysis and suicidal thoughts while taking them. A study by researchers at the University of British Columbia noted an increased risk of intestinal obstruction, a disorder in which food is prevented from passing through the small or large intestine, and pancreatitis, or inflammation of the pancreas.

Drug labels already include warnings about pancreatitis and certain types of intestinal obstruction. Changes in vision are also listed as a possible side effect of Ozempic and Wegovy.

The US study, published on Wednesday, analysed data on 16,827 patients from December 2017 to November last year. Researchers said further studies are needed to assess whether semaglutide causes the eye condition.

CNBC's Jenni Reid contributed to this report.

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