Rheumatoid Arthritis Drugs Linked To Increased Infection Risks, Other Side Effects: Report

A new analysis of adverse event reports submitted to the FDA suggests that users of rheumatoid arthritis drugs, such as Enbrel, Humira, and Remicade, may be more likely to experience a serious infection. 

Hundreds of incidents involving tuberculosis, sepsis, and even herpes have been linked to all types of rheumatoid arthritis drugs, according to a new report by AdverseEvents.com.

The group examined adverse event reports submitted to the FDA involving tumor necrosis factor (TNF) blockers, including Enbrel, Humira, Remicade, Cimzia and Simponi, as well as non-TNF drugs, such as Actemra, Arava, Imuran, Orencia, Rituxan, and Xeljanz. The findings suggest that the drugs may lower patients’ resistance to infections, providing a potential safety signal.

Rheumatoid arthritis is an autoimmune disorder that causes inflammation of the joints. It affects about 1% of the population. Most drugs that are used to treat the condition suppress the autoimmune system to some degree. The ailment costs the global health market $14 billion annually.

Both TNF Alphas and non-TNF drugs showed increased risks in upper respiratory tract infections, bronchitis, nasopharyngitis, candida infections and herpes viral infections, though the rates varied from drug to drug and some did not show any increases in various ailments.

Out of all the drugs tested, only Orencia and Xeljanz did not show increased risks for tuberculosis. Remicade was the drug most linked to TB, with more than 1,600 reports.

The non-TNF drugs showed elevated reporting of anemia and pancytopenia, and sepsis and liver problems appeared to also be more common in those types of drugs.

In addition, a deadly brain infection, known as progressive multifocal leukoencephalopathy (PML), was limited exclusively to the non-TNF drugs Rituxan, Imuran, and Arava.

TNF-alpha drugs had far and away the most adverse event reports, but the drugs are much more widely used than their non-TNF counterparts.

According to the report, Enbrel had the most adverse events reported where it was the primary suspect drug. Since it was approved in 1998, the drug has been linked to 278,283 adverse event reports. That was followed by Humira, approved in December 2002, with 229,853 adverse event reports. No other drugs came close.

A number of other studies have linked TNF-alpha drugs with increased risks of cancer as well.

The medications TNF alpha drugs are blockbuster treatments, with Humira alone generating sales of $6.5 billion in 2010.

In September 2008, the FDA issued a warning to health care professionals that TNF blockers carried the risk of fungal infections, including histoplasmosis, blastomycosis and coccidioidmycosis. Some of those infections could be life-threatening, the agency warned.