Safety of etanercept in psoriasis: a critical review

Conventional systemic treatments for patients with psoriasis are associated with multiple adverse effects that require continuous monitoring. The introduction of new biological agents such as etanercept, a fully human fusion protein, has permitted individualisation of patients' treatment according to disease stage. The drug is a competitive inhibitor of tumour necrosis factor-alpha (TNFalpha) that prevents interaction between this cytokine and its cell surface receptors. Etanercept also modulates the activity of other inflammatory cytokines and does not induce complement-mediated cell lysis in vitro. The main source of information regarding etanercept safety comes from studies in patients with rheumatoid arthritis. The most common adverse effect during drug administration is mild injection site reactions. There is no increase in the overall incidence of infections compared with placebo, although there have been several reports of infections caused by intracellular organisms (Mycobacterium tuberculosis, Listeria monocytogenes, and Mycobacterium avium intracellulare). Therefore, combination of this drug with corticosteroids must be carefully monitored and should be avoided in patients with established sepsis. There are no data showing that treatment with etanercept results in an increase in the occurrence of malignant neoplasms. However, caution is recommended in use of etanercept in patients with a current or past history of demyelinating disease. Etanercept must be used with extreme caution in patients with heart failure because of several reports indicating a worsening or de novo occurrence of congestive heart failure while receiving the drug. Monitoring of autoantibodies is not currently considered necessary as they do not predict response, toxicity or autoimmune events. The presence of non-neutralising antibodies to the TNF receptor fragment or other protein components of etanercept has not been related to a decrease in drug response or adverse reactions. Etanercept does not generally modify the course of inflammatory bowel disease. When combined with other systemic therapies for psoriasis, current data do not show an increase in adverse events. In patients with hepatitis C viral infection, etanercept does not increase transaminase levels or viral load and in some instances has allowed the concomitant use of interferon which had previously been discontinued because of a worsening of psoriasis. Etanercept is rated as a US FDA category B drug in pregnancy. However, its use is not recommended in pregnant women unless the benefit-risk ratio greatly favours its use. Etanercept is not recommended for use in lactating women. Etanercept represents a relevant treatment for psoriasis, efficacious over many weeks and safe but special care should be taken to avoid the potential risks.