Etanercept

Dimeric fusion protein: human p75 TNF receptor linked to Fc portion of IgG1.

Indications

Rheumatoid arthritis resistant to other DMARDs. Juvenile rheumatoid arthritis refractory to or intolerant of other DMARDs.

Mechanism

Binds to TNFα and thus prevents it binding to cell surface TNFR.

Method of administration

25 mg sc twice weekly. t_½=115 h. May be given with methotrexate, but not necessarily.

Efficacy

Marginally better than methotrexate in RCT. Significant response compared to placebo in terms of patient assessment, physician assessment, radiological assessment.

Evidence

ERA trial:.

Adverse effects

All rare. Sepsis, life-threatening infection. Demyelination (so contra-indicated in multiple sclerosis). Pancytopaenia, aplastic anaemia.