What are the risks of biologic therapy in rheumatoid arthritis? An update on safety.

The tumor necrosis factor-alpha (TNF-alpha) blockers infliximab and etanercept and the recombinant interleukin 1 (IL-1) receptor antagonist anakinra are effective in patients with active rheumatoid arthritis (RA). Here, information in the medical literature and public domain is used to consider the safety of these biologic agents. TNF-alpha inhibition with infliximab has been associated with reactivation of tuberculosis and possibly development of other opportunistic infections (histoplasmosis, listeriosis. and pneumocystis). Exacerbations of multiple sclerosis and other central nervous system events have been reported with etanercept and infliximab. Recently, a review of preliminary data from an ongoing phase II study suggests that infliximab may worsen congestive heart failure. On the basis of clinical trials, there appears to be a higher incidence of serious infections seen in anakinra patients compared with controls; the particular combination of anakinra and etanercept may be associated with a higher incidence of serious infections and clinically significant leukopenia. Additional data are needed to understand whether all these safety issues are unique to an individual biologic agent or representative of a class effect. At this time, treating physicians must carefully weigh the benefits of these new biologics against their risks, particularly in patients at risk of infection.