Th17 Inhibitors in Active Psoriatic Arthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

BACKGROUND: Several biologics targeting the Th17 pathway have been developed for the treatment of psoriatic arthritis (PsA), a disabling disease with moderate response and an increased incidence of serious infections to first-line biologics (TNF-α antagonists). Th17 inhibitors could replace TNF-α antagonists as first-line biologic agents. We determined the overall treatment effect of Th17 pathway inhibitors compared to placebo or active control on American College of Rheumatology (ACR) 20 response at week 12 (primary objective), risk of infections, discontinuation of treatment due to adverse events, and serious adverse events during the placebo-controlled period (12-24 weeks) in adults with active PsA in published randomized controlled trials.

METHODS: The SCOPUS database was searched. The Cochrane risk of bias tool was used for assessing quality. The pooled relative risk (RR) was derived from random effects models.

RESULTS: Seven randomized controlled trials were included which randomized 1,718 patients to Th17 inhibitors and 840 to placebo. Patients treated with Th17 inhibitors had an RR of 2.04 (95% CI: 1.79-2.33; p < 0.001) for achieving an ACR20 response at week 12 (I2 = 0%; p = 0.89) compared to placebo-treated patients. There was no evidence of publication bias. The result was consistent for study phase and outcome (ACR50/70), mechanism of action and TNF-α naivety. RR of infections was 1.06 (0.91-1.23), that of candida infections was 3.35 (0.75-14.95), that of serious adverse events was 0.82 (0.42-1.59) and that of discontinuation of treatment was 0.54 (0.31-0.93) among treated versus placebo subjects. No incident cases of tuberculosis were reported.

CONCLUSION: In patients with active PsA, biologics targeting the Th17 axis produce a clinically significant improvement in joint disease activity with acceptable safety and tolerability for short-term treatment compared to placebo.