Post-marketing safety surveillance and adverse event risk factors of abemaciclib: a pharmacoepidemiologic study.

Abemaciclib, the first highly selective cyclin-dependent kinase 4 and 6 inhibitor, is widely used in breast cancer therapy. However, investigations into its adverse drug reactions remain scant. The aim of this study was to perform data mining on adverse events (AEs) associated with abemaciclib and to identify potential risk factors. Using data extracted from the US Food and Drug Administration Adverse Event Reporting System (FAERS) for the period of July 2017 to September 2024, abemaciclib-associated AEs were analyzed for signal detection. The analysis employed four disproportionality algorithms: the reporting odds ratio, the proportional reporting ratio, the Bayesian Confidence Propagation Neural Network, and the Multi-item Gamma Poisson Shrinker. AE signal differences between patients aged 18-64 and ≥ 65 years were compared, with age effects analyzed via univariate logistic regression. A total of 98 AE signals associated with abemaciclib were identified, spanning 15 System Organ Classes. Among these, 21 signals were not explicitly documented in the product label. Additionally, signals like macrocytosis (n = 4) may be statistically unstable due to small sample sizes (n < 5). These findings require validation via large-scale studies and do not yet represent established AEs. Univariate logistic regression analysis revealed that age ≥ 65 years was associated with increased reporting odds for interstitial lung disease and blood creatinine increased. This study highlights the critical need for timely identification and continuous updating of adverse drug reaction information. Heightened vigilance for unlabeled reactions and attention to therapeutic drug monitoring, particularly dose adjustment in older adults, are warranted.