Objective: There is a lack of real-life studies on interleukin-17 (IL-17) inhibition in psoriatic arthritis (PsA). We assessed real-life 6- and 12-month effectiveness (i.e., retention, remission, low disease activity [LDA], and response rates) of the IL-17 inhibitor secukinumab in PsA patients overall and across 1) number of prior biologic/targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs), 2) years since diagnosis, and 3) European registries.

Methods: Thirteen quality registries in rheumatology participating in the European Spondyloarthritis Research Collaboration Network provided longitudinal, observational data collected as part of routine care for secondary use. Data were pooled and analyzed with Kaplan-Meier plots, log rank tests, Cox regression, and multiple linear and logistic regression analyses.

Results: A total of 2,017 PsA patients started treatment with secukinumab between 2015 and 2018. Overall secukinumab retention rates were 86% and 76% after 6 and 12 months, respectively. Crude (LUNDEX adjusted) 6-month remission/LDA (LDA including remission) rates for the 28-joint Disease Activity Index for Psoriatic Arthritis, the Disease Activity Score in 28 joints using the C-reactive protein level, and the Simplified Disease Activity Index (SDAI) were 13%/46% (11%/39%), 36%/55% (30%/46%), and 13%/56% (11%/47%), and 12-month rates were 11%/46% (7%/31%), 39%/56% (26%/38%), and 16%/62% (10%/41%), respectively. Clinical Disease Activity Index remission/LDA rates were similar to the SDAI rates. Six-month American College of Rheumatology 20%/50%/70% improvement criteria responses were 34%/19%/11% (29%/16%/9%); 12-month rates were 37%/21%/11% (24%/14%/7%). Secukinumab effectiveness was significantly better for b/tsDMARD-naive patients, similar across time since diagnosis (<2/2-4/>4 years), and varied significantly across the European registries.

Conclusion: In this large real-world study on secukinumab treatment in PsA, 6- and 12-month effectiveness was comparable to that in previous observational studies of tumor necrosis factor inhibitors. Retention, remission, LDA, and response rates were significantly better for b/tsDMARD-naive patients, were independent of time since diagnosis, and varied significantly across the European countries.