How ENBREL Works
Although the exact cause of rheumatoid arthritis (RA) is unknown, elevated levels of TNF are found in the involved tissues and fluids of patients with RA. Elevated levels of TNF are also found in the tissues and fluids of patients with psoriatic arthritis and ankylosing spondylitis (AS).1,2
ENBREL is a moderate to severe rheumatoid arthritis treatment and fully human soluble tumor necrosis factor (TNF) receptor. ENBREL is a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human 75 kilodalton (p75) tumor necrosis factor receptor (TNFR) linked to the Fc portion of human IgG1.1
ENBREL was designed to bind specifically to TNF and block its interaction with cell surface TNF receptors, thereby modulating the biological responses induced or regulated by TNF. These are the inflammatory responses that play an important part in RA, psoriatic arthritis, AS and juvenile idiopathic arthritis.1,3
ENBREL binds to TNF, limiting the amount of active TNF.1
Tumor necrosis factor (TNF; yellow) attaches to TNF "receptors" (purple) on immune cells, which trigger a cellular response.
This response can be modulated by soluble TNF receptors that are released from cells.
ENBREL (orange/purple) works like the body's soluble TNF receptors, capturing TNF before it attaches to these immune cells.
ENBREL has a mean half-life of ~4.3 days.
After administration of 25 mg of ENBREL to 25 patients with rheumatoid arthritis, a mean ± standard deviation half-life of 102 ± 30 hours was observed with clearance of 160 ± 80 mL per hour.1
ENBREL has not been shown to induce neutralizing antibodies.
Non-neutralizing antibodies were detected in approximately 6% of adult patients on ENBREL. There was no apparent correlation of antibody development to clinical response or adverse events.4
The observed incidence of any antibody positivity is highly dependent on several factors. Therefore, comparison of the incidence of antibodies to ENBREL with the incidence of antibodies to other products may be misleading.
The clinical significance of these attributes is not known.
Learn more about:
ENBREL and Moderate to Severe Rheumatoid Arthritis
ENBREL and Psoriatic Arthritis