Risk of infection with biologic antirheumatic therapies in patients with rheumatoid arthritis

There are currently 10 licensed biologic therapies for the treatment of rheumatoid arthritis in 2014. In this article, we review the risk of serious infection (SI) for biologic therapies. This risk has been closely studied over the last 15 years within randomised controlled trials, long-term extension studies and observational drug registers, especially for the first three antitumour necrosis factor (TNF) drugs, namely infliximab, etanercept and adalimumab. The risk of SI with the newer biologics rituximab, tocilizumab, abatacept and tofacitinib is also reviewed, although further data from long-term observational studies are awaited. Beyond all-site SI, we review the risk of tuberculosis, other opportunistic infections and herpes zoster, and the effect of screening on TB rates. Lastly, we review emerging opportunities for stratifying the risk. Patients can be risk-stratified based on both modifiable and non-modifiable patient characteristics such as age, co-morbidity, glucocorticoid use, functional status and recent previous SI.