Risk of histoplasmosis and other invasive fungal infections associated with Enbrel
Amgen Canada, on behalf of Immunex, in collaboration with Health Canada, has informed HealthCare Professionals of updated safety information regarding Enbrel ( Etanercept ).
Enbrel is a soluble form of a fully human tumour necrosis factor ( TNF ) receptor currently authorized in Canada for the treatment of rheumatoid arthritis, psoriatic arthritis, juvenile idiopathic arthritis, ankylosing spondylitis and plaque psoriasis. It is estimated that over 500,000 patients have been administered Enbrel worldwide.
Amgen Canada has recently revised the Boxed Warning and Warnings and Precautions ( Infections ) sections of the Enbrel Product Monograph to clarify information regarding the risk of invasive fungal infections, including histoplasmosis, in patients taking Etanercept.
• There have been reports of serious pulmonary and disseminated histoplasmosis, coccidioidomycosis, blastomycosis infections, sometimes with fatal outcomes, in patients taking tumour necrosis factor-a blockers ( TNF blockers ), including Enbrel;
• Histoplasmosis and other invasive fungal infections have not been recognized consistently in patients taking TNF blockers. This has led to delays in instituting appropriate treatment, sometimes resulting in death;
• For a patient taking a TNF blocker who presents with signs and symptoms of systemic illness, such as fever, malaise, weight loss, sweats, cough, dyspnea, and/or pulmonary infiltrates, the Healthcare Professional should ascertain if the patient has lived or worked in or traveled to areas of endemic mycoses. If so, appropriate empiric antifungal treatment may be initiated while a diagnostic workup is being performed. As with any serious infection, the TNF blocker should be stopped until the infection has been diagnosed and adequately treated.
Although no histoplasmosis infections were reported among 17,696 patients from the United States and Canada who were treated with Enbrel in 38 clinical trials and 4 cohort studies involving all authorized indications, postmarketing cases of serious and sometimes fatal fungal infections, including histoplasmosis, have been reported with TNF blockers, including Enbrel.
A TNF blocker may be restarted after recovery from the infection. The decision to restart a TNF blocker should include a re-evaluation of the benefits and risks of the TNF blocker. Both the decision to restart TNF blocker therapy and the duration of antifungal therapy should be made in consultation with an infectious disease specialist, when feasible.
Prescribers should discuss with patients and their caregivers the risk for infections while receiving TNF blockers, including infections caused by viruses, fungi, or bacteria including tuberculosis. Patients should be encouraged to promptly seek medical attention for symptoms such as weight loss, persistent fever, sweating, cough, shortness of breath, or fatigue.
Source: Health Canada, 2009
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