By Heather McKenzie

Pictured: Physician with notepad/iStock, Everyday better to do everything you love
The European Medicines Agency recently flagged a safety signal regarding the potential for glucagon-like peptide-1 receptor agonists to cause thyroid cancer. The documentation—the first step taken by the regulator toward investigation of potential adverse events in approved products—comes as demand for the popular diabetes and weight loss drugs reaches a fever pitch.
The safety signal reported by the EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) in April covers a range of glucagon-like peptide-1 receptor (GLP-1) agonists, including semaglutide, the key ingredient in Novo Nordisk’s Wegovy, Ozempic and Rybelsus. Supplemental information was also requested from Eli Lilly, Sanofi and AstraZeneca, all of which manufacture drugs in this class.
GLP-1 is a hormone that stimulates insulin secretion after eating, enabling a feeling of fullness and regulating blood sugar. GLP-1 agonists mimic the effects of this hormone, making them an effective treatment for diabetes and obesity.
An EMA spokesperson told BioSpace in an email that the discussion that led to the safety signal for the GLP-1 class followed the publication of a November 2022 study by Julien Bezin and colleagues suggesting there might be an increased risk of thyroid cancers with the use of these medicines in patients with Type 2 diabetes (T2D). In the paper, published in Diabetes Care, the authors claimed to have found that the use of the drugs for 1–3 years was associated with an increased risk of all thyroid cancer and medullary thyroid cancer, though the study is not without criticism.
The PRAC agreed on a list of questions to be addressed to the makers of these drugs while the committee reviews the available evidence, the spokesperson said.
A causal association between semaglutide and thyroid cancer has not been demonstrated in large-scale clinical trials and post-marketing surveillance, Lars Otto Andersen-Lange, media relations director at Novo Nordisk, told Reuters on June 22.
Michael Glickman
Michael Glickman, an obesity medicine specialist at Revolution Medicine, Health & Fitness, added that it is “extremely reassuring” that GLP-1 medications have been on the market for almost 20 years, with Eli Lilly and Amylin Pharmaceuticals’ Byetta (exenatide) approved by the FDA for T2D in 2005. Several others have since followed, not just for T2D but for obesity and overweight as well.
“For a modern medicine to be on the market for that long and to not have shown any obvious long-term problems is very good,” he told BioSpace. “In general, when medications are proven to have cancer links, they’re discovered relatively quickly.”