RA Therapy Not Linked to Increased Risk of Malignancy

A recent meta-analysis of randomized, controlled trials does not suggest increased risk of malignancy in patients with rheumatoid arthritis (RA) receiving biologic therapies

Mandy Huggins, MD

September 18, 2012 – The use of biologic response modifier (BRM) therapies in patients with rheumatoid arthritis (RA) does not appear to be linked to increased risk of malignancy, according to the findings of a large meta-analysis – findings that contradict those of many previous studies.

Maria A. Lopez-Olivo, MD, PhD at The University of Texas MD Anderson Cancer Center, Houston, and colleagues reported their findings in the September 5, 2012, issue of the Journal of American Medical Association.

The authors reviewed 63 randomized, controlled trials that compared the safety of BRMs with placebo and/or traditional disease-modifying antirheumatic drugs in patients with RA. The primary outcome studied was occurrence of malignancy. Follow-up was at least 24 weeks.

Rheumatoid arthritis, which affects approximately 1% of the population, is a systemic inflammatory polyarthritis. The first line of treatment is disease-modifying antirheumatic drugs, although many patients do not respond to or tolerate these medications. BRMs provide clinical improvement for these patients by targeting specific immune pathways and reducing inflammation.

According to US and European registry data published in 2010, 25% to 56% of patients with RA used BRMs. However, concerns exist regarding the safety of these drugs. Specifically, there is concern regarding increased risk of malignancy or infection, based on the drugs’ mechanism of action as well as adverse event reporting. This study is the first systematic review to evaluate such risk.

Out of 29,423 patients, 211 malignancies were reported, including 65 in the control group. There was an increased risk of malignancy at 52 weeks noted in the group treated with combination therapy of methotrexate plus tumor necrosis factor inhibitor, a type of BRM. However, this increase was not noted at other time points or with monotherapy.

The findings of this study do not suggest an overall increased risk of malignancy in RA patients receiving BRM treatment after 6 months of follow-up. However, the authors note that, “Additional systematic reviews of observational studies are needed to establish risk in the longer term.”

The study was not funded or supported by any organization. All authors reported no financial conflicts of interest.

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