The European Medicines Agency (EMA) has reported that Wegovy and Ozempic, two widely used drugs from Novo Nordisk, may, in very rare instances, lead to a serious eye condition that can cause vision loss. The agency’s safety committee announced the review on June 6.

Past research involving patients with type-2 diabetes had already associated Ozempic with non-arteritic anterior ischemic optic neuropathy (Naion). This marks the first time a regulatory body has officially acknowledged this potential side effect.

According to the EMA, Naion could affect up to 1 in every 10,000 individuals who use semaglutide, the active ingredient found in Wegovy, Ozempic, and Novo’s other diabetes medication, Rybelsus, for at least a year.

After glaucoma, Naion is the second most prevalent cause of blindness resulting from optic nerve damage.

“This has been reported as a potential risk for some time, so I think the clinical community is relatively aware of it. I don’t see this as making any major difference to prescribing patterns,” said Barclays analyst Emily Field.

Shares of the Danish drugmaker listed in the US saw an increase of nearly 2.5 percent in early trading following the announcement.

EMA Requests Label Updates

The EMA, having initiated its review in December, has requested that Novo Nordisk include Naion as a very rare side effect in the product details accompanying medications containing semaglutide.

“This has been reported as a potential risk for some time, so I think the clinical community is relatively aware of it.”

Novo Nordisk has stated its intention to collaborate with the EMA to update the drug labels. The company added that clinical trials and post-market studies have not indicated a reasonable possibility that the drugs cause the condition.

according to a statement from Novo,the “benefit-risk profile of semaglutide remains favourable”.

Market Context and Competition

Novo Nordisk has recently faced concerns from investors about perhaps losing its early lead in the competitive obesity treatment market. This led to the replacement of chief executive Lars Fruergaard Jorgensen in May.

Currently, Wegovy and Eli Lilly’s Zepbound dominate the weight-loss drug market, which is projected to reach approximately US$150 billion by the next decade.

The EMA noted that several extensive studies involving type-2 diabetes patients suggest that using Novo’s drugs could double the risk of developing Naion.

One study, involving nearly 350,000 diabetes patients and published in March, revealed that the risk of developing Naion more than doubled after two years of treatment with Ozempic, compared to patients using other types of medications.

The US Department of Health and Human Services has not yet responded to requests for comment regarding whether the Food and Drug Management (FDA) is investigating this potential side effect.