Effectiveness and drug survival of TNF-inhibitors in the treatment of psoriatic arthritis: A prospective cohort study

Abstract

Background and objectives: Tumor necrosis factor (TNF)-inhibitors are used to treat psoriatic arthritis (PsA), but only a limited number of observational studies on this subject have been published thus far. The aim of this research was to analyze the effectiveness and drug survival of TNF-inhibitors in the treatment of PsA.

Methods: PsA patients identified from the National Register for Biologic Treatment in Finland (ROB-FIN) starting their first, second, or third TNF-inhibitor treatment between 2004 and 2014 were included. Effectiveness was measured using ACR and EULAR response criteria and modeled using ordinal logistic regression. Treatment persistence was analyzed using Kaplan-Meier survival analysis and Cox proportional hazards model.

Results: The study comprised 765 patients and 990 TNF-inhibitor treatment courses. EULAR moderate treatment responses at 6 months were achieved by 68% and 37% of the users of the first and the second or the third biologic, respectively. The probabilities of discontinuing the treatment within 12 and 24 months were 20% and 28%, respectively. Adjusted treatment responses to all TNF-inhibitors were similar; however, co-therapy with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) was not associated with better effectiveness. Adalimumab [hazard ratio (HR) = 0.62; 95% confidence interval (CI): 0.44-0.88] was superior to infliximab in drug survival while etanercept (HR = 0.77, 95% CI: 0.55-1.1) and golimumab (HR = 0.75, 95% CI: 0.46-1.2) did not differ from it. Co-medication with csDMARDs did not statistically improve drug survival.

Conclusion: All available TNF-inhibitors showed similar treatment responses with or without csDMARDs. Adalimumab was associated with better drug survival when compared to infliximab.

Keywords: Cohort study; Drug survival; Methotrexate; Psoriatic arthritis; TNF-inhibitor; Treatment response.