Treatment of rheumatoid arthritis with etanercept with reference to disease-modifying anti-rheumatic drugs: long-term safety and survival using prospective, observational data

Abstract

The objective of this study was to examine the long-term safety of etanercept (ETN) in comparison with conventional DMARDs in a large observational cohort of RA patients in the UK. Data were made available from the British Society of Rheumatology Biologics Register for a cohort of patients with RA treated with ETN and a reference cohort of RA patients treated with conventional DMARDs (maximum follow-up 10 years). The adjusted risk of events was compared using Cox proportional hazards models. There were 3529 eligible ETN-treated patients (16,919 person-years) and 2864 conventional DMARD-treated patients (11,095 person-years), with notable differences between groups at baseline. Crude mortality rates were 12.0 vs 20.1 events per 1000 person-years for ETN and conventional DMARD patients, respectively, with an adjusted hazard ratio (aHR) of 0.72 (95% CI 0.54, 0.96). There was no difference in the long-term risk of serious infections (aHR = 1.02, 95% CI 0.83, 1.25). However, the risk was increased for ETN in the first 2 years (aHR = 1.56, 95% CI 1.16, 2.09; aHR = 1.32, 95% CI 1.06, 1.65). The aHRs (95% CIs) of various outcomes were cancer, 0.84 (0.68, 1.03); lymphoproliferative malignancy specifically, 0.51 (0.28, 0.95); all other serious adverse events, 0.70 (0.56, 0.87) and cardiac events specifically, 0.52 (0.37, 0.72). There was no evidence of adverse outcome from long-term exposure to ETN. There was evidence of improved survival, reduced cardiovascular events and reduced lymphoproliferative malignancies.