Overview of benefit/risk of biological agents.

Targeted tumor necrosis factor-alpha antagonists, first approved by the FDA in 1998, have had a significant impact on the treatment of patients with rheumatoid arthritis. In general, the benefit/ risk ratio for these agents and the IL-1 receptor antagonist, anakinra, has been quite favorable. However, infrequent adverse events can be serious and require continued pharmacovigilance. Infections, particularly tuberculosis and less commonly fungal infections, are among the most serious adverse events, especially given delays in diagnosis due to subtle or atypical presentations. Questions have also arisen regarding whether anti-TNF-alpha agents increase the risk of lymphoma, a complicated issue confounded by the multiple risk factors for lymphoma in patients with rheumatoid arthritis and low observed incidence rates of lymphoma, requiring prolonged monitoring. Additional rare reported complications include systemic lupus erythematosus-like syndromes, congestive heart failure and demyelinating syndromes (including cases resembling progressive multifocal leukoencephalopathy). Ongoing post-marketing surveillance of these and other serious adverse events is necessary to determine the true incidence rates, and whether a reassessment of the overall risk-benefit of tumor necrosis factor-alpha antagonists will be required.