Etanercept

Indications

Etanercept is used for: Rheumatoid arthritis, Ankylosing spondylitis, Juvenile idiopathic arthritis, Psoriatic arthritis, Plaque psoriasis

Adult Dose

Subcutaneous Rheumatoid arthritis Adult: 25 mg twice wkly at intervals of 3-4 days or 50 mg once wkly. Discontinue treatment if no response after 6 mth for rheumatoid arthritis, and after 12 wk for ankylosing spondylitis. Ankylosing spondylitis Adult: 25 mg twice wkly at intervals of 3-4 days or 50 mg once wkly. Discontinue treatment if no response after 6 mth for rheumatoid arthritis, and after 12 wk for ankylosing spondylitis. Chronic moderate to severe plaque psoriasis Adult: Initially, 25 mg twice wkly or 50 mg once wkly. Alternatively, 50 mg twice wkly at intervals of 3-4 days for up to 12 wk, then reduce to 25 mg twice wkly or 50 mg once wkly. Continue treatment until remission is achieved, up to 24 wk. Discontinue if no response after 12 wk. Psoriatic arthritis Adult: 25 mg twice wkly at intervals of 3-4 days or 50 mg once wkly. Discontinue treatment if no response after 12 wk.

Child Dose

Subcutaneous Juvenile idiopathic arthritis Child: >2 yr 0.4 mg/kg (max: 25 mg) twice wkly at intervals of 3-4 days, or alternatively, 0.8 mg/kg (max: 50 mg) once wkly. Discontinue treatment if no response after 6 mth or initial response is not maintained. Chronic moderate to severe plaque psoriasis Child: Chronic severe plaque psoriasis: >6 yr 0.8 mg/kg once wkly for up to 24 wk. Max: 50 mg wkly. Discontinue if no response after 12 wk. Psoriatic arthritis Child: >12 yr 0.4 mg/kg (max: 25 mg) twice wkly at intervals of 3-4 days, or alternatively, 0.8 mg/kg (max: 50 mg) once wkly. Discontinue treatment if no response after 6 mth or initial response is not maintained.

Renal Dose

Administration

SC Preparation For a more comfortable injection, leave prefilled syringe/autoinjector/reconstituted vial at room temperature for ~15-30 minutes before injecting Do not remove the needle cover while allowing to reach room temperature SC Administration Rotate injection sites Clean injection site area with alcohol wipe and let skin dry Inject SC in top of thighs, abdomen (avoid 2-inch area around navel), or outer area of upper arm Do not inject areas of skin that are tender, bruised, red, or hard Avoid injecting area with scars or stretch marks For psoriasis, avoid injecting directly into raised, thick, red, or scaly skin patch or lesion

Contra Indications

Sepsis or risk of sepsis; active infections including chronic or localised infections.

Precautions

Patient w/ history of recurring or chronic infections or w/ underlying conditions that may predispose patient to infections (e.g. advanced or poorly controlled DM); previous hepatitis B virus infection; history of hepatitis C, blood dyscrasias; pre-existing or recent onset of demyelinating disease; CHF, moderate to severe alcoholic hepatitis. Childn. Pregnancy and lactation. Serious infection risk Increased risk of developing serious infections resulting in hospitalization or death; most patients were taking concomitant immunosuppressants (eg, methotrexate, corticosteroids) Patients older than 65 years may be at greater risk Discontinue if patient develops serious infection or sepsis Malignancy Lymphoma and other malignancies, some fatal, have been reported in children and adolescents treated with tumor necrosis factor (TNF) blockers Cases of acute and chronic leukemia have been reported in association with postmarketing TNF-blocker use in rheumatoid arthritis (RA) and other indications; patients with RA may be at higher (approximately 2-fold greater) risk for leukemia than general population Monitoring Parameters Monitor CBC w/ differential; signs/symptoms of infection (prior to, during and after therapy), heart failure, hypersensitivity reactions, lupus-like syndrome, malignancy. Perform screening for latent TB (prior to and during therapy), hepatitis B virus (HBV); HBV carriers.

Pregnancy-Lactation

Pregnancy Available studies during pregnancy do not reliably support an association between therapy and major birth defects; clinical data are available from the Organization of Teratology Information Specialists (OTIS) Enbrel Pregnancy Registry in women with rheumatic diseases or psoriasis and a Scandinavian study in pregnant women with chronic inflammatory disease; Both studies showed the proportion of liveborn infants with major birth defects was higher for women exposed to etanercept compared to diseased etanercept unexposed women; however, the lack of pattern of major birth defects is reassuring and differences between exposure groups (e.g. disease severity) may have impacted the occurrence of birth defects The risk of fetal/neonatal adverse reactions with in utero exposure to therapy is unknown; risks and benefits should be considered prior to administering live or live-attenuated vaccines to infants exposed to drug in utero Lactation Limited data from published literature show that etanercept is present in low levels in human milk and minimally absorbed by a breastfed infant; no data are available on effects of therapy on breastfed child or on milk production

Interactions

May interfere w/ troponin determinations; other assays using murine monoclonal antibodies (e.g. creatine kinase-MB fraction, folate, β-HCG, thyrotropin, thyroxine, vancomycin).

Adverse Effects

Side effects of Etanercept : >10% RA Infection (81%) Upper respiratory infections (65%) Non-upper respiratory infections (54%) Injection site reactions (43%) Diarrhea (16%) Rash (13%) 1-10% RA Pruritus (5%) Pyrexia (2%) Urticaria (2%) Hypersensitivity (1%) Potentially Fatal: Serious infections and sepsis (e.g. TB, invasive fungal infections), malignancies (e.g. breast, lung and skin cancers; lymphoma). Rarely, pancytopenia, aplastic anaemia, central and peripheral demyelinating events, lupus, lupus-related conditions and vasculitis; anaphylaxis.

Mechanism of Action

Etanercept binds to tumour necrosis factor (TNF) and blocks its interaction w/ cell surface tumour necrosis factor receptors, thus preventing TNF-mediated cellular responses by rendering TNF biologically inactive.