US drug watchdog orders new safety warnings for weight-loss drugs over potential risk of vision loss

The US Food and Drug Administration (FDA) is requiring manufacturers of GLP-1 medicines to update their safety labels to warn of a potential increased risk of a rare but serious eye condition that can cause permanent vision loss. The US drug watchdog FDA on Monday said the weight-loss drugs had been associated with non-arteritic anterior ischaemic optic neuropathy (NAION), a condition that can lead to sudden, painless loss of vision in one eye, including permanent vision loss. The new warning requirements cover all GLP-1 receptor agonists, a class of medicines widely used to treat type 2 diabetes and obesity. They include popular treatments such as Novo Nordisk's Ozempic and Wegovy, Eli Lilly's Mounjaro and Zepbound, as well as other medicines in the class. The FDA's assessment included an analysis of 126 clinical trials involving over 134,000 patients. The agency also reviewed real-world data and published observational studies. While it acknowledged limitations in the available evidence, it concluded that a potential increased risk warranted additional warnings across the drug class. The move adds to the safety scrutiny surrounding a rapidly expanding class of medicines that has become central to the treatment of obesity and type 2 diabetes. Last year, Europe’s medicines watchdog (EMA) determined that NAION should be classified as a very rare side effect of semaglutide, the active ingredient of some weight-loss medicines, affecting up to one in 10,000 patients.