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

OBJECTIVES: 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 toTNFis.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. METHODS: 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. RESULTS: 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%). CONCLUSIONS: 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.