The safety of infliximab, combined with background treatments, among patients with rheumatoid arthritis and various comorbidities: a large, randomized, placebo-controlled trial.

OBJECTIVE

To assess the risk of serious infections following 22 weeks of infliximab therapy, and to further characterize the safety profile of infliximab in combination with background treatments during 1 year in patients with rheumatoid arthritis (RA) with various comorbidities.

METHODS

Patients with active RA despite receiving methotrexate (MTX) were randomly assigned to receive infusions of placebo (group 1, n=363), 3 mg/kg infliximab (group 2, n=360), or 10 mg/kg infliximab (group 3, n=361) at weeks 0, 2, 6, and 14. At week 22, patients in placebo group 1 began receiving 3 mg/kg infliximab, and patients in group 3 continued to receive an infliximab dose of 10 mg/kg. Patients in group 2 who failed to meet predefined response criteria received increasing doses of infliximab in increments of 1.5 mg/kg.

RESULTS

At week 22, the relative risk of developing serious infections in groups 2 and 3, compared with group 1, was 1.0 (95% confidence interval [95% CI] 0.3-3.1, P=0.995) and 3.1 (95% CI 1.2-7.9, P=0.013), respectively. The incidence of serious adverse events was 7.8% in groups 2 and 3 compared with 7.5% in group 1. From week 22 to week 54, 11.8%, 9.9%, and 10.3% of patients in groups 1, 2, and 3, respectively, reported occurrences of serious adverse events. Through week 54, 1 patient in group 1, 2 patients in group 2, and 4 patients in group 3 developed active tuberculosis.

CONCLUSION

The risk of serious infections in patients receiving the approved infliximab dose of 3 mg/kg plus MTX was similar to that in patients receiving MTX alone. Patients receiving the unapproved induction regimen of 10 mg/kg infliximab plus MTX followed by a 10 mg/kg maintenance regimen had an increased risk of serious infections through week 22.