Real-world individual and comparative analysis of adverse event reporting for adalimumab and etanercept using public FDA adverse event reporting system data

Objective: We analyzed adverse events (AEs) related to adalimumab and etanercept using the Food and Drug Administration Adverse Event Reporting System (FAERS) to detect unexpected AEs. Subsequently, we compared the discrepancy in serious outcomes involving the same injection site reactions (ISRs) between two different medications.

Methods: Four algorithms, including reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and the multi-item gamma Poisson shrinker (MGPS) were used to identify AE signals. These signals were standardized to preferred terms (PTs), and categorized at the system organ classification (SOC) level using the MedDRA system for further analysis. Serious outcomes were defined as death, disability, hospitalization, or life-threatening. The term "multiple serious outcomes" refers to instances that involve two or more of these serious consequences.

Results: Adalimumab had 186,697 AE reports (736 PTs and 28 SOCs), while etanercept had 289,989 AE reports (294 PTs and 21 SOCs). At the PT level, we identified new unexpected AEs in adalimumab that related to multiple serious outcomes like intestinal obstruction, osteoarthritis, hernia, paternal drugs affecting the fetus, intestinal fistula, anal fistula, and postoperative adhesion. At the PT level of etanercept, we discerned unanticipated AEs related to multiple serious outcomes such as knee arthroplasty, joint destruction, finger deformity, and Felty's syndrome. At the SOC level, we paid special attention to the gastrointestinal disorders in adalimumab, with many unexpected PTs, as well as the vascular disorders and cardiac disorders in etanercept. For both drugs, the most common SOC is general disorders and administration site conditions, with ISRs being the most prevalent AEs within this category. The results indicate that etanercept has a greater variety of serious outcomes involving shared ISRs than adalimumab (p < 0.01) and also exhibits higher reported rates for these serious consequences (p < 0.01).

Conclusion: Upon individual analysis, we identified unanticipated AEs in adalimumab and etanercept, respectively. Comparative analysis suggests that, despite similar ISRs, etanercept necessitates heightened vigilance due to its potential for more serious outcomes.