Effectiveness and Persistence of The First Tumor Necrosis Factor Inhibitor In Portuguese Psoriatic Arthritis Patients

Abstract

Tumor necrosis factor inhibitors (TNFi) dramaticaly improved the management of psoriatic arthritis (PsA). Nevertheless, a significant proportion of patients do not respond and/or are intolerant to TNFis. The objective of this work was to assess the effectiveness, measured by response rates and drug survival, and the main reasons for TNFi discontinuation, in PsA patients. This was a retrospective non-interventional study of PsA patients registered at the Rheumatic Diseases Portuguese Registry, with at least 1 TNFi prescription. Data was analyzed at 0, 3, 6, 12, 24, 36 and 48 months after starting a first TNFi. Response was measured by composite disease activity (DAS, ACR, PsARC, BASDAI, ASDAS, MDA) and functional (HAQ) indices. Drug survival was assessed by Kaplan-Meier survival analysis. In all analyses significance level was set at 0.05. 705 PsA patients were included, with a mean age of 52.5 years (±13.3); 50.8% (n=358) female. 185 patients (26.24%) treated with adalimumab, 322 (45.67%) etanercept, 100 (14.18%) golimumab and 98 (13.90%) with infliximab. The average response rates, measured by composite disease activity and functional indices, are shown in Table 1. The average drug persistence was of 31.79±17.03 months for TNFi as a group, with 205 (29.08%) of discontinuations during a period of 4 years of follow-up. The main reasons for discontinuation of the first TNFi were: non-response/loss of response 111 (54.15%), adverse event 48 (23.41%), surgery 6 (2.93%), refusal to continue treatment, 4 (1.95%), loss to follow-up 3 (1.46%), pregnancy 4 (1.95%), death 2 (0.98%), remission 2 (0.98%), and others 10 (4.88%). PsA patients receiving a first TNFi will persist on treatment for an average of 2.6 years with treatment discontinuations rates of 29.08%. Non-response/loss of response constitutes the major reason for treatment discontinuation in this population.