PT  - JOURNAL ARTICLE
AU  - Suzanne Arends
AU  - Eveline van der Veer
AU  - Henk Groen
AU  - Pieternella M. Houtman
AU  - Tim L.T.A. Jansen
AU  - Martha K. Leijsma
AU  - Johan Bijzet
AU  - Pieter C. Limburg
AU  - Cees G.M. Kallenberg
AU  - Anneke Spoorenberg
AU  - Elisabeth Brouwer
TI  - Serum MMP-3 Level as a Biomarker for Monitoring and Predicting Response to Etanercept Treatment in Ankylosing Spondylitis
AID  - 10.3899/jrheum.101128
DP  - 2011 Jun 01
TA  - The Journal of Rheumatology
PG  - jrheum.101128
4099  - http://www.jrheum.org/content/early/2011/05/30/jrheum.101128.short
4100  - http://www.jrheum.org/content/early/2011/05/30/jrheum.101128.full
AB  - Objective To investigate whether level of serum matrix metalloproteinase-3 (MMP-3) can serve as a biomarker for monitoring and predicting response to etanercept treatment in patients with ankylosing spondylitis (AS) in daily clinical practice. Methods Ninety-two consecutive AS outpatients with active disease who started etanercept treatment were included in this longitudinal observational study. Clinical data were collected prospectively at baseline and after 3 and 12 months of treatment. At the same timepoints, serum MMP-3 levels were measured retrospectively by ELISA. Results Since baseline serum MMP-3 levels were significantly higher in male compared to female patients with AS, data analysis was split for gender. Changes in serum MMP-3 levels after etanercept treatment correlated positively with changes in clinical assessments of disease activity and physical function in both male and female patients. Receiver operating characteristic analysis in male patients showed that baseline serum MMP-3 levels had poor accuracy (AUC < 0.7) to discriminate between Assessments in Ankylosing Spondylitis 20 (ASAS20) or ASAS40 responders and nonresponders after 3 or 12 months of treatment. The accuracy of change in serum MMP-3 levels from baseline to 3 months in predicting response after 3 or 12 months of treatment was poor for ASAS40 (AUC < 0.7) or moderate for ASAS20 (AUC = 0.752 and 0.744, respectively), and was not superior to the accuracy of change in the currently used objective biomarkers, erythrocyte sedimentation rate and C-reactive protein. Conclusion Although significant changes in serum MMP-3 levels were found after etanercept treatment, data analysis indicates that serum MMP-3 levels are not very useful for monitoring and predicting response to etanercept treatment in patients with AS in daily clinical practice.