Clinical Response, Drug Survival, and Predictors Thereof Among 548 Patients With Psoriatic Arthritis Who Switched Tumor Necrosis Factor α Inhibitor Therapy: Results from the Danish Nationwide DANBIO Registry

Abstract Objective To describe the frequency of treatment switching and outcomes among patients with psoriatic arthritis (PsA) who switched tumor necrosis factor α inhibitor (TNFi) agents in routine care. Methods We conducted an observational cohort study based on the Danish nationwide DANBIO registry. Treatment outcomes were evaluated using the American College of Rheumatology criteria for 20% improvement (ACR20)/ACR50/ACR70, European League Against Rheumatism (EULAR) response criteria for good response, and the 28‐joint count Disease Activity Score (DAS28) (remission). Kaplan‐Meier and regression analyses were used for drug survival analyses and to identify predictors of outcome after treatment switching. Results Of 1,422 patients starting TNFi agents, 548 patients (39%) switched to a second biologic drug during up to 10 years of followup. Median followup was 2.3 years (interquartile range [IQR] 1.0–4.3 years). Switchers were more frequently women (56% versus 45%), had a shorter disease duration (3 versus 4 years), a higher median Health Assessment Questionnaire (HAQ) score (1.1 [IQR 0.6–1.6] versus 0.9 [IQR 0.5–1.4]), DAS28 (4.8 [4.0–5.7] versus 4.4 [3.6–5.2]), pain score on a visual analog scale (VAS) (65 mm [46–77] versus 62 mm [40–75]), and fatigue score on a VAS (69 mm [50–83] versus 64 mm [42–80] mm) (all P < 0.05 at start of first TNFi). During the first and second treatment, HAQ, DAS28, and VAS scores and C‐reactive protein levels had decreased after 6 months (all P < 0.05), and median drug survival was 2.2 versus 1.3 years ( P < 0.001). Lower fatigue score increased survival of the second TNFi. After switching, the proportions of patients achieving a sustained ACR20, ACR50, ACR70, EULAR good response, and DAS28 remission after 3–6 months were 22% (number needed to treat [NNT] 4.5), 13% (NNT 7.9), 5% (NNT 20), 19% (NNT 5.3), and 34% (NNT 2.9), respectively. Response rates were lower during the second treatment (all P < 0.01 versus first TNFi). At the 2‐year visit, 47% of switchers had achieved an ACR20 response. No differences between drug–drug combinations were found. Conclusion Thirty‐nine percent of the patients with PsA switched TNFi agents. Response rates and drug survival were lower after switching; however, half of the switchers had an ACR20 response 2 years after starting the first TNFi.