Real-life Persistence of Targeted Therapy Strategy in Monotherapy Versus Combination Therapy in Patients with Rheumatoid Arthritis, Psoriatic Arthritis, and Ankylosing Spondylitis

Abstract Aim: To evaluate the persistence of the initial strategy of targeted therapy, with or without conventional synthetic (cs) disease-modifying antirheumatic drugs (DMARDs) (combination and monotherapy strategies, respectively) in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS), under real-life conditions. Methods: This is a nested cohort study within BIOBADASER III, a prospective Spanish registry of patients with rheumatic diseases who are undergoing treatment with targeted therapy including biologics (b) and targeted synthetic (ts) DMARDs. The primary outcome was to determine the initial treatment strategy persistence; switching drugs within the same class, but maintaining the initial strategy (combination or monotherapy) was considered persistence. Bivariate comparisons and multivariate Cox proportional hazard models were used for the analyses.Results: A total of 2,589 patients were included in our study. In the multivariate model, compared to monotherapy, the combination therapy strategy was associated with shorter persistence in patients with RA (hazard ratio [HR] 1.58, 95% confidence interval [CI] 1.00 to 2.50, p=0.049), PsA-Axial (HR 3.00, 95% CI 1.35 to 6.70, p=0.007), PsA-Peripheral (HR 2.58, 95% CI 1.51 to 4.39, p<0.001) and AS (HR 16.77, 95% CI 7.37 to 38.16, p<0.001). Overall, the combination strategy was associated with an increased incidence of any adverse event (incidence rate ratio [IRR] 1.13, 95% CI 1.05-1.21) but not of serious adverse events (1.02, 95% CI 0.84-1.24) compared to monotherapy,Conclusion: In this real-life study, compared to monotherapy, the strategy of combining a b/tsDMARD with a csDMARD at the start of treatment is associated with lower persistence and worse tolerability in RA, PsA and especially in AS, suggesting that combination therapy should be avoided in AS and possibly PsA patients and used cautiously in RA patients.