Can Biologics Be Discontinued in Patients with Psoriatic Arthritis in Stable Remission? A Prospective Single-CenterClinical and Ultrasound Study

Biologic disease-modifying antirheumatic drugs (bDMARDs) and particularly tumor necrosis factor inhibitors (TNFi) have dramatically changed the natural history of psoriatic arthritis (PsA), making complete clinical remission possible in most patients. However, TNFi drugs are not without potential adverse effects such as increased infectious risk. In addition, their extensive use is associated with a significant economic burden. This prospective longitudinal cohort study involving 45 PsA patients treated with TNFi in stable remission aimed to evaluate by both clinical examination and ultrasound timing and predictive factors of disease relapse after discontinuation of TNFi treatment. Thirty-nine (86.6%) of 45 enrolled patients experienced disease relapse during the follow-up period, while six patients (13.4%) maintained remission beyond the scheduled 104 weeks. The median survival time of drug-free remission after TNFi discontinuation was 24 weeks (95% confidence interval (CI): 22.6-25.4). Disease relapse was characterized by marked clinical and ultrasound worsening of dermatologic and rheumatologic conditions. However, resuming previously discontinued treatment allowed all patients to quickly regain clinical remission. Interestingly, axial involvement was a key feature of the symptomatological pattern of disease relapse, being the main reason for treatment restart in 26% of our cohort. Based on a multivariate Cox model, three variables (VAS pain, tender joint count, and swollen joint count) of the clinical assessment performed at the time point of TNFi treatment onset negatively influenced the time to disease relapse. In conclusion, temporary discontinuation of TNFi drugs is feasible and relatively safe. However, as few predictors of the risk and timing of disease relapse have been identified, patients should be closely monitored when therapy is discontinued.