Decrement of serum cartilage oligomeric matrix protein (COMP) in rheumatoid arthritis (RA) patients achieving remission after 6 months of etanercept treatment: Comparison with CRP, IgM-RF, MMP-3 and anti-CCP Ab

Objective: The aim of this study was to evaluate whether serum COMP can estimate the therapeutic response of RA after 6 months of treatment with etanercept. Methods: Forty-five RA patients receiving 25mg of etanercept twice a week for 6 months were registered in this prospective observational study. Clinical response to the therapy was evaluated by DAS 28. Laboratory variables-COMP, CRP, ESR, IgM-RF, MMP-3, and anti-CCP Ab-were assessed at baseline and after 6 months of treatment. We assessed the correlations between serum COMP and other variables and whether serum COMP is associated with DAS28 remission. Results: Serum COMP correlated with DAS28-ESR (p < 0.05, r = 0.40) at baseline. At 6 months of etanercept treatment, 10 patients entered remission (DAS28-ESR < 2.6) whereas the other 35 patients did not (DAS28-ESR > 2.6). The decrement of serum COMP at 6 months was significant in the remission group (N = 10) but not in the non-remission group (N = 35). On the other hand, CRP, ESR and MMP-3 decreased at 6 months regardless of remission status. IgM-RF titer as well as anti-CCP Ab titer did not differ at 6 months. Conclusions: Serum COMP at baseline reflects clinical disease activity of RA. Serum COMP is a valuable serologic marker to identify the subset of RA patients achieving remission during treatment with etanercept. (C) 2010 Published by Elsevier Masson SAS on behalf of the Societe Francaise de Rhumatologie.