Biologic therapies developed in the last decade for rheumatoid arthritis are not associated with an increased risk of cancer when compared with traditional treatments for the condition, according to new research from The University of Texas MD Anderson Cancer Center.

The study, published in The Journal of the American Medical Association (JAMA), is the largest systematic review evaluating the risk of developing any malignancy among rheumatoid arthritis patients using approved biologic response modifiers (BRMs), several of which include tumour necrosis factor (TNF) inhibitors.

Since 2005, conflicting data has associated TNF inhibitors with an increased risk of developing certain types of malignancies.

Because of increased cases of spontaneous lymphoma in children and adolescents, the current US Food and Drug Administration warning label notes the risk of malignancy for all TNF inhibitors.

"These results are reassuring for patients considering biologic therapies for their disease," says senior author Maria E. Suarez-Almazor, M.D., professor in the Department of General Internal Medicine at MD Anderson. "Patients are understandably concerned when treatments are linked to cancer risk. With this knowledge, clinicians can effectively demonstrate that the benefits of BRMs far outweigh the risk."

Rheumatoid arthritis affects approximately one percent of the population and can lead to significant morbidity, joint deformity and impaired quality of life. Traditional treatments for rheumatoid arthritis include disease-modifying anti-rheumatic drugs (DMARDs), like methotrexate, and anti-inflammatory medications.

BRMs are prescribed as a second line of treatment if the initial DMARDs fail. BRMs target molecules on cells of the immune system and joints, and the products that are secreted in the joints, all of which can cause inflammation and joint destruction. Between 25 and 56 percent of patients use BRMs to treat the disease, but concerns over cancer risk abound because the therapies interfere with the immune system.

The researchers – part of MD Anderson's team of internal medicine specialists dedicated to treating cancer patients for medical issues other than cancer – used the Cochrane Collaboration to analyze the results of 29,423 adult patients from 63 randomized controlled trials.

As a group, the trials selected compared the safety of all nine BRMs currently approved by the FDA against a placebo or traditional DMARD and included only patients with rheumatoid arthritis who had a minimum of six months of follow-up. The Cochrane Collection is an independent, non-profit organization that houses the largest collection of records of randomised controlled trials in the world.

They observed no statistically significant increased risk of any type of cancer in patients treated with BRMs compared with the other medications. In the trials analysed, 211 patients developed a malignancy during the trial. No significant differences existed between patients in the control group who developed cancer versus those treated with BRM therapies.

"Although additional reviews of observational studies are needed to establish any long-term risk, this is a step forward in understanding overall the risk of developing cancer when taking this newer class of medication," says Suarez-Almazor. "With these results patients and clinicians can make informed decisions about treating rheumatoid arthritis."

Source: University of Texas M. D. Anderson Cancer Center