Evaluation of the safety profile of glucagon-like peptide-1 receptor agonists: a focus on thyroid cancer-related adverse events by using the European pharmacovigilance database

Introduction: The therapeutic landscape for the treatment of type 2 diabetes mellitus (T2DM) has greatly evolved with the introduction of glucagon-like peptide-1 receptor agonists (GLP-1 RAs); however, concerns regarding their potential association with thyroid cancer have emerged. The aim of this study is to analyze individual case safety reports (ICSRs) involving GLP-1 RAs, focusing on thyroid cancer-related adverse events (AEs) using the European pharmacovigilance database. Methods: ICSRs reporting GLP-1 RAs (semaglutide, liraglutide, exenatide, lixisenatide, dulaglutide) or the dual GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) agonist tirzepatide as suspected drugs were retrieved from the EudraVigilance (EV) database from 1st January 2022 to 26th September 2024. A disproportionality analysis was performed to compare the probability of reporting thyroid cancer-related AEs among these drugs using the reporting odds ratio (ROR) and its 95% confidence interval (95% CI). Considering the different therapeutic indications, a sensitivity analysis was also conducted. Results: A total of 34,956 ICSRs were included in the analysis. The majority of AEs were experienced by adult and elderly female patients. The most reported system organ classes (SOCs) were: "gastrointestinal disorders", "general disorders and administration site conditions", and "injury, poisoning and procedural complications". Disproportionality analysis revealed that semaglutide had a lower probability of reporting thyroid cancer-related AEs than tirzepatide (ROR = 0.54, 95% CI 0.37-0.81, p < 0.05), whereas sensitivity analysis revealed no significant signals across stratified therapeutic groups. Conclusion: These findings should be interpreted with caution, given the inherent limitations of pharmacovigilance databases. Further studies are recommended to better assess the potential causal relationship between GLP-1 RAs and thyroid cancer.