AB0208 Prediction of Flare in Rheumatoid Arthritis and Psoriatic Arthritis Patients with Low Disease Activity Receiving Tnf Inhibitors: Role of Calprotectin and Drug Trough Serum Levels. A One-Year Prospective Cohort Study

Background Calprotectin and TNF antagonist (TNFa) trough serum levels are associated with disease activity. Objectives To determine if calprotectin serum levels or drug trough serum levels predict relapse in RA and PsA patients with low levels of disease activity during TNFa therapy. Methods Prospective 1-year follow-up, single center study (INMUNOREMAR cohort). RA (ACR 1987) and PsA (CASPAR) patients in clinical remission (CR) (DAS28-ESR 3.2 and increase in ΔDAS28-ESR >0.6. Univariate and multivariate regression models were used to identify predictors of disease flare. Results 103 patients (47RA, 56PsA) were included. Mean Age 57 (30–81) years. 78 (75.8%) had CR and 25 (24.2%) LDA. Mean CR/LDA duration was 58 (4–163) months. 36 patients had received treatment with ADA, 50ETN, and 17IFX. Mean biologic treatment duration 61 (7–166) months. 47.4% patients were on monotherapy, 47% on reduced dose, and 17.9% received steroids. 84 patients (91%) remained in CR/LDA for 12 months, and 12 patients (13%; 8 RA, 4 PsA) experienced flares. Patients with flares had a longer time to achieve CR/LDA [CR/LDA (n=81) 3.1 (1–6) months vs. Flare (n=12) 20 (5–31) months, p Conclusions Calprotectin and TNF trough serum levels are promising biomarkers to predict flare in RA and PsA patients with low disease activity during anti-TNF treatment. References Sanmarti et al. Ann Rheum Dis. 2015 Aug;74(8):e42. Disclosure of Interest J. Inciarte-Mundo Grant/research support from: Hospital Clinic de Barcelona (Premi E. Letang 2013); Catalan Society of Rheumatology (Research Grant 2013), M. Hernandez: None declared, V. Ruiz-Esquide: None declared, J. Ramirez: None declared, A. Cuervo: None declared, S. Cabrera-Villalba: None declared, M. Pascal: None declared, J. Yague: None declared, J. Canete: None declared, R. Sanmarti Grant/research support from: This Study was supported by an Investigator Initiated Research (IIR) from Pfizer (WS2392358)