The U.S. Food and Drug Administration announced that the manufacturers of Humira, Cimzia, Enbrel, and Remicade must strengthen the existing warnings, in the Warnings and Precaution sections of the drugs' prescribing information and Medication Guides, on the risk of developing opportunistic fungal infections. Some patients with invasive fungal infections have died.

The four drugs, known as tumor necrosis factor alpha blockers (TNF-alpha blockers), which suppress the immune system, are approved to treat a variety of conditions which may include rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, plaque psoriasis, ankylosing spondylitis, and Crohn's disease.

US FDA exercised its new authority under the Food and Drug Administration Amendments Act of 2007 to require manufacturers of TNF inhibitors to make safety-related changes to prescribing information, or labeling.

“Under the FDA's new authorities, we can require safety label changes and a risk evaluation and mitigation strategy, known as REMS, when the agency becomes aware of new safety information,” said Bob Rappaport, M.D., director of the Division of Anesthesia, Analgesia and Rheumatology Products, Center for Drug Evaluation and Research. “Requiring the risks to be highlighted will help health care professionals be more vigilant in watching for these adverse events, and is necessary to ensure that the benefits of these drugs outweigh their risks.”

Since the initial approval of the four TNF blockers, the prescribing information for these drugs has included information about the risk of serious infections, including fungal infections. However, based on reports reviewed by FDA, health care professionals are not consistently recognizing cases of histoplasmosis and other invasive fungal infections, leading to delays in treatment.

US FDA has reviewed 240 reports of histoplasmosis, an infection caused by the fungusHistoplasma capsulatum, in patients being treated with Enbrel, Humira, or Remicade. The majority of the reports involved people in the Ohio River and Mississippi River valleys (the fungus is commonly found in those areas). In at least 21 of the reports, histoplasmosis was initially not recognized by health care professionals, and antifungal treatment was delayed. Twelve of those patients died. Medication Guides will become part of a REMS for Humira and Remicade and are already part of a REMS for Enbrel and Cimzia. The manufacturers for all four of these drugs will also be required to educate prescribers about the risks.