FDA warns of arthritis drug risks

The Food and Drug Administration ordered stronger warnings Thursday on four medications widely used to treat rheumatoid arthritis and other serious illnesses, saying they can raise the risk of possibly fatal fungal infections.

The drugs -- Enbrel, Remicade, Humira and Cimzia -- work by suppressing the immune system to keep it from attacking the body. For patients with rheumatoid arthritis, the treatment provides relief from swollen and painful joints, but it’s “a double-edged sword,” said the FDA’s Dr. Jeffrey Siegel. That’s because the drugs also lower the body’s defenses to various infections.

Siegel, who heads the office that oversees arthritis drugs, said the FDA became concerned after discovering that doctors seemed to be overlooking a particular kind of fungal infection called histoplasmosis. Of 240 cases reported to the FDA in which patients taking one of the four drugs developed this infection, a total of 45 died -- about 20%.

The infection, which mimics the flu, can have grave consequences if it isn’t caught early and spreads beyond the respiratory system to other organs of the body.

Siegel said the investigation began with a woman taking one of the drugs who died of histoplasmosis. Doctors at the FDA found that the woman had been sick with the fungal infection for a long time. “This case led us to be concerned that there may be other situations in which physicians may not recognize histoplasmosis,” Siegel said.

Siegel said the FDA’s order Thursday meant the risk of histoplasmosis would be flagged in a “black box,” the strongest warning information in a drug’s prescribing literature. The four medications already have black box warnings about infection risk, but the language varies from drug to drug.

Three of the drugs, Enbrel, Humira and Remicade, are considered blockbusters, with sales of more than $1 billion annually for each. Cimzia is newer and less widely used.

Humira is made by Abbott Laboratories Inc., Cimzia by UCB, Enbrel by Amgen Inc. and Wyeth, and Remicade by Centocor, a unit of Johnson & Johnson.