Etanercept is a dimeric soluble form of the p75 TNF receptor that can bind TNF molecules. Etanercept inhibits binding of TNF-α and TNF-β (lymphotoxin alpha [LT-α]) to cell surface TNFRs, rendering TNF biologically inactive. In in vitro studies, large complexes of etanercept with TNF-α were not detected and cells expressing transmembrane TNF (that binds Enbrel) are not lysed in the presence or absence of complement.

Enbrel is a tumor necrosis factor (TNF) blocker indicated for the treatment of: Rheumatoid Arthritis (RA); Polyarticular Juvenile Idiopathic Arthritis (JIA) in patients aged 2 years or older; Psoriatic Arthritis (PsA); Ankylosing Spondylitis (AS); Plaque Psoriasis (PsO) in patients 4 years or older

Enbrel is administered by subcutaneous injection. Adult RA and PsA: 50 mg once weekly with or without methotrexate (MTX). AS: 50 mg once weekly. Adult PsO: 50 mg twice weekly for 3 months, followed by 50 mg once weekly. Pediatric PsO or JIA: 0.8 mg/kg weekly, with a maximum of 50 mg per week.

Most common adverse reactions (incidence > 5%): infections and injection site reactions.

Enbrel should not be administered to patients with sepsis.

Do not start Enbrel during an active infection. If an infection develops, monitor carefully and stop Enbrel if infection becomes serious. Consider empiric anti-fungal therapy for patients at risk for invasive fungal infections who develop a severe systemic illness on Enbrel (those who reside or travel to regions where mycoses are endemic). Demyelinating disease, exacerbation or new onset, may occur. Cases of lymphoma have been observed in patients receiving TNF-blocking agents. Congestive heart failure, worsening or new onset, may occur. Advise patients to seek immediate medical attention if symptoms of pancytopenia or aplastic anemia develop, and consider stopping Enbrel. Monitor patients previously infected with hepatitis B virus for reactivation during and several months after therapy. If reactivation occurs, consider stopping Enbrel and beginning anti-viral therapy. Anaphylaxis or serious allergic reactions may occur. (See Full Prescribing Information.)