Real-world safety profile of anifrolumab: An observational disproportionality analysis of the FAERS database

Anifrolumab is a type I interferon receptor antagonist approved for the treatment of moderate-to-severe systemic lupus erythematosus. While its efficacy has been demonstrated in clinical trials, its long-term safety remains understudied in the real world. This study extracted relevant data from the FDA Adverse Event Reporting System (FAERS) to evaluate the post-marketing safety profile of anifrolumab in real-world clinical practice and to identify potential safety signals. We analyzed 1293 reports involving 3542 adverse events (AEs) from the FAERS database (Q3 2021-Q1 2025) using disproportionality analysis. Reports in which anifrolumab was designated as the "primary suspect" drug were included. Safety signals were identified using the reporting odds ratio and the Bayesian confidence propagation neural network, with a signal defined as positive only if it met both criteria: a lower limit of the reporting odds ratio's 95% confidence interval > 1 and the 95% lower credibility interval for the information component of the Bayesian confidence propagation neural network > 0. Additionally, multivariable logistic regression analyses were performed for key AEs to rule out potential confounding. The study identified 97 positive safety signals associated with anifrolumab. In addition to the labeled AEs, such as infusion-related reactions and infections, several unexpected AEs were also identified, including renal-related, cardiovascular-related, and neurological AEs. Multivariable logistic regression analyses for key AEs showed that concomitant immunosuppressants, comorbidities, and disease severity were not significant independent predictors (all P > .05), supporting the robustness of the identified signals. This pharmacovigilance study provides hypothesis-generating evidence on the post-marketing safety profile of anifrolumab and highlights several potential safety signals that warrant further evaluation. It is crucial to emphasize that these findings are derived from the FAERS, a spontaneous reporting database that cannot establish causality due to inherent limitations, such as underreporting, missing data, and lack of exposure information. Therefore, these results require confirmation in well-designed observational studies and clinical trials. Clinicians should be aware of these potential associations and consider appropriate monitoring.