THU0261 Correlation between Time to Switch and Clinical Response Amplitude to Rituximab in Second Line Treatment in Rheumatoid Arthritis Patients with Treatment Failure to Tumor Necrosis Factor Inhibitors: 3-Year Data from Repeat Observational Study

Background In recent years we assist to an increasing interest to get more clinical data to improve the control of disease course in rheumatoid arthritis (RA) patients. According to treat to target principle, best practice still needs to be better defined in patients that encounter inadequate response after a variable period of time to anti-TNF treatment. Objectives To investigate the clinical impact of switching to rituximab (RTX) according to the length of previous anti-TNF treatment in routine practice setting in patients suffering from RA and failure to TNF inhibitors. Methods REPEAT is an open-label, multicenter, prospective observational local study, 1087 patients with active RA and inadequate response to at least one TNF inhibitor received initial RTX (2x1000 mg IV, at 2 weeks apart) and subsequent RTX courses have been enrolled from 2010 to 2013. The patients were stratified according to the length of anti-TNF treatment before switch: 24 months (group C=526). Clinical assessments including 28-joint disease activity score (DAS-28) were performed at baseline (switch moment) and after each retreatment course at 6, 12, 18, 24, 30 and 36 months. For the purpose of this analysis, median DAS-28 values were calculated for each group (A,B and C)and followed by median Delta Δ DAS-28 values calculation, as differences between values found at two successive evaluations and also from baseline to each evaluation. Statistical analyses were performed with STATA SE 11.0 software. Comparison between all previous treatments and evaluations for disease activity were performed using Nptrend and ANOVA tests. Results Median values for ΔDAS-28 obtained for group A, group B and group C from baseline to 6 months were -1,65;-1,35;-1,33 (P=0.01), from baseline to 12 months: -2,43;-2,05;-2,17 (P=0.02), from baseline to 18 months: -2,96;-2,59;-2,49 (P=0.009), from baseline to 24 months: -3,26;-2,83;-2,57 (P=0.01), from baseline to 30 months: -2,58;-2,7;-2,66 (P=0.15) and from baseline to 36 months: -2,56;-2,54;-2,83 (P=0.9). The median ΔDAS-28 achieved in group A at 1 year (-2.43) is comparable with ΔDAS-28 obtained at 18 month in group B (-2.59) and group C (-2.49). Across evaluations Nptrend test was P