Characterising infusion/injection-related reactions in patients with rheumatoid arthritis treated with biologic agents.

Objectives: Biologic disease-modifying anti-rheumatic drugs (bDMARDs) have transformed the management of rheumatoid arthritis (RA), but their efficacy can be limited by infusion/injection-related reactions (IRRs). This study investigated demographic and clinical factors associated with IRRs in patients with RA using data from the Korean College of Rheumatology Biologics & Targeted Therapy (KOBIO) Registry.

Methods: We analysed 1,832 patients with RA, categorising them into IRR and non-IRR groups. Demographic, disease characteristics, and treatment histories were compared. A Sankey plot visualised bDMARD switching patterns, and multivariable logistic regression identified IRR-independent predictors.

Results: IRRs occurred in 9.7% of patients and were significantly associated with younger age (mean 49.9 vs. 54.9 years; OR=1.793, p=0.014), secondary Sjögren's syndrome (OR=2.175, p=0.035), and prior leflunomide use (OR=1.497, p=0.015). Abatacept (OR=0.263, p<0.001), tocilizumab (OR=0.419, p<0.001), and golimumab (OR=0.345, p=0.006) were associated with reduced IRR risk compared to infliximab. Following IRRs, use of etanercept, infliximab, and adalimumab declined, while tocilizumab and Janus kinase (JAK) inhibitors increased.

Conclusions: IRRs are common among RA patients receiving bDMARDs, particularly in younger individuals or those with prior leflunomide use. Abatacept, tocilizumab, and JAK inhibitors represent safer alternatives, underscoring the need for individualised treatment strategies.