AB0376 Cartilage oligomeric matrix protein, a biomarker of arthritis, could be useful for predicting the response to biologic therapy in rheumatoid arthritis?
Authors: BI Gavrila, C Ciofu, C Mihai, G Udrea, M Bojinca, V Stoica, E Panaitescu
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> introduction of biologic therapy has revolutionized the treatment of Rheumatoid Arthritis (RA). Despite these advances, 20–40% of the patients are declared nonresponders to at least one of the therapies (1).High costs and patient exposure to severe adverse reactions (ex. infections) determined the need to identify biomarkers that can distinguish pretreatment responders versus nonresponder patients. <h3>Objectives</h3> evaluating the predictive role for the response to anti tumor necrosis factor therapy (anti-TNF) of cartilage oligomeric matrix protein (COMP), a specific serological marker, which evaluates the articular cartilage degradation and its turnover.(2) <h3>Methods</h3> prospective and observational study including 64 patients followed 12 months with active RA, uncontrolled by conventional synthetic DMARDs.Clinical assessment was performed at 0, 6 and 12 months according to ACR criteria approved by OMERACT and evaluation of treatment response according to EULAR criteria (good /moderate /nonresponder). <h3>Results</h3> of the 64 patients included in the study, 59 (92.2%) were women and 5 (7.8%) men, mean age 57.55±9.42 years. After 6 months, 7 patients were declared nonresponders, 38 achieved a moderate response and 19 good response. Following baseline COMP titres and the EULAR response at 6 months, general tests identified significant differences between groups. Lower baseline titres had predictive value for achieving a good response (746.04±130.095 ng/ml) comparing with moderate responders (1032.8±188.671ng/ml) and nonresponders (1042.2±181.717 ng/ml, p=0.0000). After 12 months 11 patients achieved moderate response, 44 a good response and just 1 patient was declared nonresponder. At this visit, even if we didn9t find significant differences between baseline COMP titres and the EULAR response (p=0.1430), we observed lower baseline titres for good responders (917.8±219.943 ng/ml) versus moderate responders (1042.7±193.117 ng/ml). Grouping patients in 2 categories (responders/nonresponders) there were no differences between groups at 6 months (937.27±218.106 ng/ml versus 1042.2±181.717 ng/ml, p=0.227) or 12 months (942.82±219.025 ng/ml versus 896.5±0.000 ng/ml, p=0.9753). Following the status pretreatment of COMP and EULAR response at 6 months, we identified differences between groups (p=0,0001), all 7 patients declared nonresponders were COMP positive and only 13/19 (68.4%) of good responders were tested positive. At 12 months there were no differences between pretreatment status of COMP and response to treatment (p=0.2805). Regarding the evolution of serum levels, we noticed a decrease statistically significant from baseline (948.75±215.683 ng/ml) to 12 months (740.88±227.04 ng/ml, p=0.0000). <h3>Conclusions</h3> COMP could be one of the biomarkers for identifying pretreatment the patients who will respond to biologic therapy in Rheumatoid Arthritis. <h3>References</h3> Chaves Chaparro LM, Salvatierra Ossorio J, Raya Άlvarez E Reumatol Clin. 2011 Mar-Apr; 7(2):141–4. Morozzi G, Fabbroni M, Bellisai F, Cucini S, Simpatico A, Galeazzi MClin Rheumatol. 2007 Aug; 26(8):1335–8. <h3>Disclosure of Interest</h3> None declared