A black box warning was issued in 2008 for etanercept (Enbrel) regarding the risk for tuberculosis and other infections.
Previously, Enbrel prescribing information included a bold-face warning regarding the risk of infections and tuberculosis. The information is now in a boxed warning – the strongest warning that the FDA requires – and includes additional language regarding screening and monitoring patients for tuberculosis, including patients who tested negative for latent tuberculosis infection. In addition, the boxed warning states that tuberculosis has been observed in patients receiving TNF-blocking agents, including Enbrel, and that tuberculosis may be due to reactivation of latent tuberculosis infection or to new infection.
The boxed warning notes that data from clinical trials and preclinical studies suggest that the risk of reactivation of latent tuberculosis infection is lower with Enbrel than with TNF-blocking monoclonal antibodies. The boxed warning further notes that, nonetheless, post-marketing cases of tuberculosis reactivation have been reported for TNF blockers, including Enbrel.
Clinical studies enrolling more than 20,000 patients worldwide have shown cases of tuberculosis in approximately 0.01% of patients treated with Enbrel. In trials enrolling more than 15,000 patients in the United States and Canada, about 0.007% of those patients treated with Enbrel developed tuberculosis.