Uptake and effectiveness of newer biologic and targeted synthetic disease-modifying antirheumatic drugs in psoriatic arthritis: results from five Nordic biologics registries

Background We aimed to describe the uptake of newer biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) in psoriatic arthritis (PsA) in the Nordic countries and to compare their retention and effectiveness. Methods Patients with PsA starting a b/tsDMARD in 2012-2020 in five Nordic rheumatology registers were included. Uptake and patient characteristics were described, with comorbidities identified from linkages to national patient registries. One-year retention and 6-month effectiveness (proportions achieving low disease activity (LDA) on the Disease Activity Index for PSoriatic Arthritis based on 28-joint evaluation) for the newer b/tsDMARDs (abatacept/apremilast/ixekizumab/secukinumab/tofacitinib/ustekinumab) were compared with adalimumab through adjusted regression models stratified by treatment course (first, second/third, and fourth or more). Results In total, 5659 treatment courses with adalimumab (56% biologic-naïve) and 4767 courses with a newer b/tsDMARD (21% biologic-naïve) were included. The uptake of newer b/tsDMARDs increased from 2014 and plateaued in 2018. Patient characteristics appeared similar across treatments at treatment start. Adalimumab was more often used as the first course and newer b/tsDMARDs more often in biologic-experienced patients. Used as a second/third b/tsDMARD, the retention rate and the proportion achieving LDA were significantly better for adalimumab (rate 65%, proportion 59%) compared with abatacept (45%, 37%), apremilast (43%, 35%), ixekizumab (LDA only, 40%) and ustekinumab (LDA only, 40%), but not significantly different from other b/tsDMARDs. Conclusion Uptake of newer b/tsDMARDs occurred mainly in biologic-experienced patients. Regardless of mode of action, only a minority of patients starting a second or later b/tsDMARD course remained on drug and achieved LDA. Superior outcomes for adalimumab indicate that the positioning of newer b/tsDMARDs in the PsA treatment algorithm remains to be established.