Eight-year retention rate of first-line tumor necrosis factor inhibitors in spondyloarthritis : A multi-center retrospective analysis

Objective. To evaluate the 8-year survival of the first TNF inhibitor (TNFi) in patients with axial spondyloarthritis (axSpA) or psoriatic arthritis (PsA), identify the predictive factors for withdrawal, and compare the discontinuation rates for infliximab, etanercept, and adalimumab. Methods. We evaluated PsA and axSpA patients treated with a first-line TNFi between 2005 and 2015 at four Italian tertiary centres. 8-year drug survival was calculated by Kaplan-Meier method and risk for discontinuation among treatment groups compared by stratified log-rank test. Univariate and multivariate Cox proportional hazard models were developed to examine predictors of withdrawal. Results. Out of 614 patients (316 axSpA, 298 PsA), 203 received adalimumab, 131 etanercept, and 280 infliximab, with similar frequencies in axSpA and PsA subgroups. The cumulative 8-year retention rate in the whole population was 55.1% (57.2 and 51.9% and for axSpA and PsA, respectively; p=NS). No significant differences were observed in drug persistence among individual TNFi in either group. Male sex (HR 0.595, 95% CI 0.405-0.875; p=0.008) and concomitant methotrexate use (HR 0.648, 95% CI 0.426-0.985; p=0.042) were associated with a lower risk of withdrawal in PsA and high baseline BASDAI (HR 0.9842 95% CI 0.9708-0.9980; p=0.028) in axSpA. No difference was found in the comparative analysis of reasons for discontinuation between PsA and axSpA. Conclusion. We reported that the real-life 8-year retention rate of the first TNFi in axSpA and PsA is over 50%, with no significant differences between axSpA and PsA and irrespective of the individual TNFi.