Clinical and pharmacological experience with etanercept

Tumour necrosis factor (TNF) is the dominant mediator of the cytokine cascade that causes inflammation and joint destruction in rheumatoid arthritis (RA). A new class of agent under investigation, the biological TNF inhibitors, inhibit the activity of TNF. Recombinant human TNF receptor p75 Fc fusion protein (TNFR:Fc; etanercept) blocks the activity of the cytokine TNF. Etanercept (Enbrel) was recently approved by the Food and Drug Administration for the treatment of RA. Etanercept is a genetically engineered recombinant soluble TNF receptor fusion protein that binds to TNF body and inhibits its biologic action; it is the first biotechnology product approved for the treatment of RA. Remarkable progress has been achieved in the treatment of RA with the development of TNF antagonists. Recent clinical trials have improved our understanding of the major role played by the cytokine TNF in provoking joint inflammation in RA.