Arthritis Drugs May Up Cancer Risk
Study Also Shows TNF-Blockers May Increase Risk of Infection
May 16, 2006 -- Rheumatoid arthritisRheumatoid arthritis patients who take the newer biologic medications have a threefold increase in cancercancer risk over patients who don't take them, a new analysis suggests.
Researchers also concluded that the patients taking the tumor necrosis factor (TNF)-blocking drugs Remicade and Humira were twice as likely to develop serious infections.
Rheumatoid arthritisarthritis patients are at increased risk for infections, regardless of their treatment, and recent studies indicate that patients are also more likely to develop malignancies.
In rheumatoid arthritis, the body's immune system attacks the joints and sometimes other organs. For those patients with moderate to severe disease, drugs (such as TNF blockers and methotrexate) which help suppress the immune system can be used for treatment.
Putting Risk in Perspective
The new analysis, published in the May 17 issue of The Journal of the American Medical Association, offers some of the strongest evidence yet that TNF-blocking drugs, which have been used by more than half a million patients, further increase the risk of malignancies.
Patients should be made aware of the risks associated with treatment, but these risks should not be overstated, says researcher Eric Matteson, MD, of the Mayo Clinic in Rochester, Minn.
He points out that the long-term cancer risk among patients who use the drugs is not known because none of the studies has lasted much longer than a year.
"Rheumatoid arthritis is a bad disease, and patients have severe functional limitations and even decreased life expectancy," he tells WebMD. "There is no question that these drugs represent a major advance in the treatment of this disease. The drugs improve function, reduce joint destruction, and even improve survival."
Higher Doses, More Cancers
Three TNF-inhibiting biologics have been approved for the treatment of rheumatoid arthritisrheumatoid arthritis - Remicade, Humira, and Enbrel.
Enbrel studies were not included in the analysis because the drug acts somewhat differently than the other two medications. But there is no suggestion that it is any safer or less safe than the others with regard to cancercancer and infection risk, Matteson says.
The analysis included nine trials of Remicade and Humira involving 3,493 patients treated with the TNF-blocking antibodies and 1,512 patients treated with placebo instead of the biologics. The shortest trial in the analysis was 12 weeks long and the longest was 54 weeks.
All data on serious infections (such as pneumoniapneumonia) and cancers were pooled; the cancer risk among patients taking the biologics was found to be 3.3 times that of placebo-treated patients.
Twenty-nine malignancies were reported among the roughly 3,500 patients who got the active biologic, compared to three malignancies among the roughly 1,500 placebo-treated patients.
The most cancers were seen among patients treated with the highest doses of the TNF-inhibiting drugs; lymphomas and basal cell cancers were the most commonly reported malignancies.