High disease relapse after bDMARD spacing in psoriatic arthritis compared to rheumatoid arthritis and axial spondyloarthritis patients: real-life data from BIOPURE registry

The objective is to evaluate the effectiveness of a spacing strategy of bDMARDs in a cohort of selected patients in disease remission or low-disease activity (LDA) without glucocorticoids affected with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). This was a single-centre study carried out on patients prospectively enrolled in the biologic Apulian registry. Patients whose disease was in remission or LDA without taking glucocorticoids during the previous 6 months and who had agreed to increase the time interval between bDMARD doses were included in this study. Demographic and clinical characteristics were recorded at baseline and at 3, 6 and 12 months of follow-up. Endpoint of the study was the survival of spacing doses in the time lag of the study. Failure of spacing was defined as the first flare of disease. Thirty-seven RA, 28 PsA and 20 axSpA patients underwent bDMARD spacing according to a local strategy. During the follow-up, 5 RA, 6 PsA and 4 axSpA patients had a joint flare, but further 5 PsA patients manifested a skin relapse. Global persistence was 86.5% for RA (MST = 41 (95% CI: 37-45) months) and 80% for axSpA patients (MST = 36 (95% CI: 31-42) months). PsA patients showed a lower persistence, being of 60.7% (MST = 30 (95% CI: 23-36) months) (log-rank test, p = 0.03). Dose reduction by spacing bDMARD doses may be a feasible approach in patients with persistent remission/LDA activity. However, PsA patients might have greater odds of spacing failure because of skin psoriasis relapse.