What is known and objective: Despite being effective, the biologics approved for treating rheumatoid arthritis have been associated with serious adverse events. This study is aimed at comparing the safety profiles of adalimumab, etanercept and infliximab by analysing the disproportionalities of the associations between the different adverse events and the different biologics in the Portuguese spontaneous reporting database.
Methods: Adverse events spontaneously reported to the Portuguese pharmacovigilance system (PPS) between 2009 and 2011 were included. Adverse events were classified according to MedDRA in the primary system organ class. The reporting odds ratio (ROR) and its 95% confidence intervals (CI) were calculated for each biologic regarding the various categories of adverse events. Microsoft Excel was used to perform all the calculations.
Results and discussion: The PPS received 12167 adverse events reported for all drugs, of which 741 were reported for biologics: 157 for adalimumab, 132 for etanercept and 452 for infliximab. Compared with the all other drugs, adalimumab, etanercept and infliximab were all disproportionately associated with 'infections and infestations' (ROR: 6·65, 95% CI: 4·50-9·83; ROR: 2·74, 95% CI: 1·56-4·81; ROR: 2·95, CI 95%: 2·16-4·02, respectively) and with 'neoplasms benign, malignant and unspecified' (ROR: 7·23, 95% CI: 3·92-13·33; ROR: 6·26, 95% IC: 3·12-12·57; ROR: 3·94, 95% CI: 2·41-6·44, respectively), etanercept with 'general disorders and administration site conditions' (ROR: 2·08, 95% CI: 1·44-3·02) and infliximab with 'immune system disorders' (ROR: 5·17, 95% CI: 3·50-7·64), 'respiratory, thoracic and mediastinal disorders' (ROR: 1·80, 95% CI: 1·31-2·48) and 'investigations' (ROR: 1·82, 95% CI: 1·19-2·78). When interpreting the results one should take into consideration the number of patients exposed and should not only rely on the number of adverse events reported.
What is new and conclusion: Although the disproportionalities found for adalimumab and etanercept may suggest strong associations with particular adverse events, caution is needed when drawing conclusions on the association between infliximab and the adverse events analysed. In the light of the present findings, these results deserve further evaluation.
Keywords: adverse events; biologics; pharmacovigilance; reporting odds ratio; rheumatoid arthritis; spontaneous reporting.
© 2014 John Wiley & Sons Ltd.