Rheumatoid Arthritis Disease-modifying Antirheumatic Drug Intervention and Utilization Study: Safety and Etanercept Utilization Analyses from the RADIUS 1 and RADIUS 2 Registries

Objective. To report the rates of serious adverse events (SAE), serious infectious events (SIE), and events of medical interest (EMI) in patients receiving etanercept; to identify the risk factors for SAE, SIE, and EMI; and to report time to switching from etanercept therapy, reasons for switching, and time to restarting treatment with etanercept in patients with rheumatoid arthritis (RA) in US clinical practice. Methods. Adults >= 18 years of age who fulfilled the 1987 American Rheumatism Association criteria for RA were eligible for enrollment in 2 prospective, 5-year, multicenter, observational registries. RADIUS 1 (Rheumatoid Arthritis DMARD Intervention and Utilization Study) enrolled patients with RA who required a change in treatment [either an addition or a switch of a biologic or nonbiologic disease-modifying antirheumatic drug (DMARD)]. In RADIUS 2, patients with RA were required to start etanercept therapy at entry. Patients were seen at a frequency determined by their rheumatologist. RADIUS 1 and RADIUS 2 were registered under the US National Institutes of Health ClinicalTrials.gov identifiers NCT00116714 and NCT00116727, respectively. Results. In these patients, SAE. SIE, and EMI occurred at rates comparable to those seen in clinical trials. No unexpected safety signals were observed. Rates for SAE, SIE, and EMI in etanercept-treated patients were comparable to rates observed in patients receiving methotrexate monotherapy and did not increase with greater exposure to etanercept therapy. Conclusion. The RADIUS registries provide a better understanding of the safety of etanercept in patients with RA in the US practice setting. (First Release Oct 15 2010; J Rheumatol 2011;38:21-8; doi:10.3899/jrheum.100347)