Psoriatic Arthritis Treatment Significantly Improves Response Rates

Patients who responded to brodalumab showed improvement in skin condition and joint swelling.

A new drug for the treatment of psoriatic arthritis (PsA) exhibited promising results in reducing the effect of some symptoms of the disease during a recent study.

Results of the study, which were published on June 12, 2014, in the New England Journal of Medicine, found that patients who responded to brodalumab showed improvement in their skin condition and in swelling of the toes and fingers. Brodalumab acts as an inhibitor for the activity of interleukin-17A, which plays a key role in the pathogenesis of PsA, according to the study.

The study evaluated the effectiveness of brodalumab in 168 patients with a median age of 52 years. Of the patients in the study, 57 received 140 mg of brodalumab, 56 received 280 mg of brodalumab, and 55 received a placebo over the course of a year.

Patients eligible for the study were classified as having active PsA with 3 or more tender joints and 3 or more swollen joints.

At the 12-week mark, patients taking 140 mg and 280 mg of brodalumab showed higher response rates (37% and 39% respectively) than those who took a placebo (18%). Additionally, 14% of patients taking either dose of brodalumab showed a 50% improvement in symptoms based on the American College of Rheumatology (ACR) response criteria, compared with 4% who were given the placebo.

Disease activity scores were found to improve significantly for both brodalumab groups compared with placebo after 12 weeks.

At 24 weeks, the rate of 20% improvement in the ACR criteria (ACR20) in the 140-mg group of patients was 51% and in the 280-mg group was 64%, which compared favorably with an ACR20 rate of 44% in patients who switched from placebo to 280 mg of brodalumab during the extension phase.

ACR20 response rates were 37% and 36% in the 140-mg and 280-mg groups, respectively, for patients who never received biologic therapy before, compared with 20% in the placebo group. For patients who had received prior biologic therapy, ACR20 was achieved in 37% of the 140-mg group and 42% of the 280-mg group compared with 16% in the placebo group.

In the 140-mg group, 62% of patients reported adverse events, while in the 280-mg group 71% of patients reported adverse events, and in the placebo group 65% reported adverse events. The most common adverse events in both brodalumab groups were upper respiratory tract infection, fatigue, diarrhea, and headache.

The researchers concluded that the clinical response to brodalumab indicates that suppression of interleukin-17 pathways is critical to reducing the impact of psoriatic skin and joint disease.

“There is accumulating evidence that interleukin-17 is central to the pathogenesis of psoriatic arthritis and other spondyloarthritides, such as ankylosing spondylitis,” the study authors wrote. “Inhibition of interleukin-17 signaling by brodalumab also induced significant clinical responses in patients with psoriasis. By contrast, efficacy has not been observed for brodalumab in clinical trials involving patients with rheumatoid arthritis or Crohn’s disease. Differential responses in patients with rheumatoid arthritis versus those with psoriatic arthritis provide further evidence that these diseases have different causal mechanisms.”