Risk of malignancies in patients with rheumatoid arthritis treated with biologic therapy: a meta-analysis

Concerns exist regarding the potential development of malignancies in patients with rheumatoid arthritis (RA) who are receiving biologic response modifiers (BRMs).

To assess the risk of malignancy in patients with RA enrolled in randomized controlled trials (RCTs) of BRMs.

Electronic databases, conference proceedings, and websites of regulatory agencies were searched for RCTs evaluating abatacept, adalimumab, anakinra, certolizumab, etanercept, golimumab, infliximab, rituximab, and tocilizumab in RA from inception through July 9, 2012.

Independent selection of studies included RCTs that compared the safety of any BRMs used in RA patients with placebo and/or any traditional disease-modifying antirheumatic drugs with a minimum of 24 weeks of follow-up.

Independent reviewers selected studies and extracted data on quality and outcomes. Pooled estimates and 95% confidence intervals were calculated for each BRM.

Sixty-three RCTs with 29,423 patients were analyzed. No statistically significant increased risk of developing malignancy was observed. Of the 29,423 patients, 211 developed a malignancy during the trial (118 solid tumors, 48 skin cancers, 14 lymphomas, 5 hematologic nonlymphomas, and 26 not specified). The incidence rate for any malignancy during the first year of therapy was very low in the BRM plus methotrexate group (0.77%; 95% CI, 0.65%-0.92%), the BRM monotherapy group (0.64%; 95% CI, 0.42%-0.95%), and the controls (0.66%; 95% CI, 0.52%-0.84%). Anakinra plus methotrexate showed lower odds compared with methotrexate alone (Peto odds ratio, 0.11; 95% CI, 0.03-0.45). No statistically significant risk was observed for specific cancer sites, although the Peto odds ratio for lymphoma was 2.1 (95% CI, 0.55-8.4) in patients receiving tumor necrosis factor inhibitors compared with controls.

The use of BRMs among patients with RA included in RCTs of at least 6 months' duration was not significantly associated with an increased risk of malignancy compared with other disease-modifying antirheumatic drugs or with placebo.