Sirukumab Shows Promise in Hard-to-Treat Rheumatoid Arthritis

The investigational drug sirukumab shows promise in the treatment of active refractory rheumatoid arthritis (RA).

Sirukumab is a human monoclonal antibody that selectively binds to the interleukin-6 cytokine with high affinity. In the multicenter, double-blind, parallel-group, randomized, placebo-controlled, phase 3 SIRROUND-T study, investigators sought to examine the safety and efficacy of the drug in the treatment of RA.

Included in the study were 878 patients 18 or older with active RA, who had 4 or more of 68 tender joints and 4 or more of 66 swollen joints, and were refractory or intolerant to prior treatment with at least 1 anti-TNF drug.

The patients were randomized 1:1:1 via a central interactive voice or web response system to receive either placebo every 2 weeks, 50 mg of sirukumab every 4 weeks, or 100 mg of sirukumab every 2 weeks. All treatment options were administered for 52 weeks or less.

Sixty percent of patients had previously received 2 or more biological treatments including non-TNF drugs, and 19% of patients were not taking a DMARD at baseline.

The results of the study, published in The Lancet, showed that at week 16, 40% of patients who received 50 mg of sirukumab every 4 weeks achieved an ACR20 response. Forty-five percent of patients who received 100 mg of sirukumab every 2 weeks achieved an ACR20 response versus 24% who received placebo.

“We were able to demonstrate this in one of the largest study populations to date, with around 900 patients in 35 countries,” said investigator Daniel Aletaha. “Despite having previously received treatments with biologic drugs, these patients still had a persistently active disease. Treatment options had been practically exhausted for many of these patients. However, even in this group of patients, treatment with sirukumab brought about a significant reduction in the inflammatory action of the disease.”

Incidence of adverse events (AEs) in the 24-week period were similar across all groups, and the most common AE was injection site erythema. At week 52, the most common AE for all patients administered sirukumab—–including those reassigned from placebo––was injection site erythema again.

“These results are very significant in the case of a progressive, inflammatory, musculoskeletal disease such as rheumatoid arthritis, especially for those patients who are resistant to treatment,” Aletaha said.