Enbrel, Humira Side Effects Caused More Injuries Than Any Other Drugs in 2014: Report

The arthritis drugs Humira and Enbrel accounted for more adverse event reports last year than any other medications, according to a recent analysis of adverse event reports submitted to the FDA. 

The Institute for Safe Medication Practices (ISMP) released its QuarterWatch report (PDF) last month, finding that Humira and Enbrel each had tens of thousands of injury reports in the FDA’s adverse event reporting program.

Enbrel (entanercept) and Humira (adalimumab) are drugs used to treat auto-immune disorders like rheumatoid arthritis , psoriasis, and Crohn’s disease. They belong to a class of medications known as tumor necrosis factor (TNF) blockers and are the most widely prescribed drugs of the class.

The ISMP report indicates that in 2014 Humira ranked number one out of all drugs monitored by the group, with 46,937 reports of patient injury. Enbrel came in a relatively close second, with 38,929 reports. The median number of adverse event reports associated with the 1,604 drugs monitored by ISMP is 37.

When broken down to only the most serious adverse events reported in the U.S., Enbrel was number 1 and Humira was second.

“To generate an unequalled number of adverse event reports over one year requires a combination of three factors: A substantial patient population, numerous toxic effects, and extensive manufacturer contact with patients and health professionals,” the QuarterWatch report notes. “Both drug products are administered with self-injection syringes. Both drugs also accounted for large numbers of injection site reactions, with more than 10,000 reported cases each in 2014.”

However, most of those reports did not lead to serious injuries, ISMP found. The more serious reports included cases of infection and cancer, as well as reports of hypersensitivity.

The findings are similar to the findings outlined in a report published by AdverseEvents.com this summer, which indicated that 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.