'No malignancy risk' with biologic response modifiers

By Liam Davenport, medwireNews Reporter

Rheumatoid arthritis (RA) patients treated with biologic response modifiers (BRMs) for at least 6 months do not have a greater risk for malignancy than those given other disease-modifying drugs or placebo, conclude US and Spanish researchers.

However, the team, writing in the Journal of the American Medical Association, cautions: "Although the findings suggest that BRMs may be generally safe with respect to risk of malignancy in the short term, the risk of recurrence in patients with [RA] with history of cancer or cancer risk factors remains unknown."

Maria Suarez-Almazor, from the University of Texas MD Anderson Cancer Center in Houston, Texas, USA, and colleagues identified 63 studies reporting safety data for a total of 29,423 RA patients treated with abatacept, adalimumab, anakinra, certolizumab, etanercept, golimumab, infliximab, rituximab, or tocilizumab.

Over follow-up periods ranging from 24 to 156 weeks, 211 malignancies developed, including 118 solid tumors, 48 skin cancers, and 14 lymphomas. The remaining tumors were either not specified or hematologic nonlymphomas.

The overall malignancy rate was 0.72%, and 0.64% in BRM monotherapy groups, 0.77% in BRM combination-therapy groups, and 0.66% in control groups, consisting of patients given traditional disease-modifying antirheumatic drugs or placebo.

The only statistically significant increase in malignancy risk was observed for combined tumor necrosis factor (TNF) inhibitor plus methotrexate treatment versus control treatment, at a Peto odds ratio of 2.1 at 52 weeks' and an attributable risk percentage of 52%. None of the other permutations showed a significantly increased malignancy risk, including when the TNF inhibitors were used alone.

Interestingly, the team notes that anakinra plus methotrexate significantly lowered the risk for malignancy compared with methotrexate alone at 24 weeks', at a Peto odds ratio of 0.11, a prevented risk percentage of 89%, and an absolute risk reduction of nine per 1000 treated patients.

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