Novo Nordisk weight loss drugs linked to rare eye condition: study

Investors at Novo Nordisk appeared unfazed Thursday by a critical Harvard report linking weight-loss drugs to a rare eye condition.

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

However, analysts said the research results were “hardly a game-changer”. Shares in the Danish pharmaceutical company’s stock were little changed on Thursday, falling in early morning trading before rising 0.1% at 11:17 a.m. London time.

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

While the research report does suggest “some correlation” with a rare ocular event, the quality of the evidence is “very low and the margins of error are very wide,” said Deutsche Bank analyst Emmanuel Papadakis.

The worst-case scenario would likely be further tweaks to the warnings on the drugs’ labels, which is “hardly a game-changer,” Papadakis said.

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

A Novo Nordisk spokesperson said the optic nerve disease NAION is not an “adverse event associated with marketed formulations of semaglutide” according to the approved labeling. They added that there are “important 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 resulting from the use of our medicines very seriously,” the spokesperson said.

The popularity of its blockbuster drugs has made Novo Nordisk the most valuable company in Europe, with a valuation last year that was higher than Denmark’s entire gross domestic product.

Wegovy has also been shown to have health benefits beyond weight loss and blood sugar control. The Food and Drug Administration approved it in March for use in reducing the risk of heart disease.

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

The drugs’ labels already include warnings about pancreatitis and certain types of intestinal obstruction. Changes in vision are also listed as possible side effects for both Ozempic and Wegovy.

The U.S. study, published Wednesday, analyzed data from 16,827 patients from December 2017 through November last year. The researchers noted that more research is needed to determine whether semaglutide causes the eye condition.

CNBC’s Jenni Reid contributed to this report.